deceleration?
A = (V2 - V1) /T
A = (6 mi/hr - 25 mi/hr)/10 s
A = -19 mi/hr/10 s
A = -1.9 mi/hr/s
9. A motorcycle traveling at 25 m/s accelerates at a rate of 7.0 m/s2 for 6.0 seconds. What is the
final speed of the motorcycle?
V2 = V1 + AT
V2 = 25 m/s + (7 m/s2 * 6 s)
V2 = 67 m/s
10. A car starting from rest accelerates at a rate of 8.0 m/s2. What is its f inal speed at the end of 4.0
seconds?
V2 = V1 + AT
V2 = 0 m/s + (8 m/s2 )(4 s)
V2 = 32 m/s
11. After traveling for 6.0 seconds, a runner reaches a speed of 10 m/s. What is the runner’s
acceleration?
A = (V2 - V1 )/T
A = (10 m/s - 0 m/s)/6 s
A = 1.67 m/s2
12. A cyclist a ccelerates at a rate of 7.0 m/s2. H ow long will it take the cyclist to reach a speed of 18
m/s?
T = (V2 - V1)/A
T = (18 m/s - 0 m/s)/7 m/s2
T = 2.57 s
13. A skateboarder traveling at 7 .0 meters per second rolls to a stop at the top of a ramp in 3.0
seconds. What is the skateboarder’s a cceleration?
A = (V2 - V1 )/T
A = (0 m/s - 7 m/s)/3 s
A = -7 m/s/3 s
A = -2.3 m/s2
Quiz: Motion
Name: Amy Zhang Date: 3/1
Formulas:
A= v2 −v1 V2 = V 1 + (a * T) T= V2−V1
T2 a
1. After traveling for 1 4.0 seconds, a bicyclist reaches a s peed of 89 m/s. What is the runner’s
acceleration?
A= V2−V1
T
A= 89 m/s − 0 m/s
14 s
A= 89 m/s
14 s
A = 6.36 m/s2
2. A car starting from rest accelerates at a rate of 18.0 m/s2 . What is its f inal speed at the end of
5.0 seconds?
V2 = V1 + AT
V2 = 0 m/s + (18 m/s2 )(5 s)
V2 = 90 m/s
3. A cyclist a ccelerates at a rate of 16.0 m/s2 . How long will it take the cyclist to reach a s peed of
49 m/s?
T= V2−V1
A
T= 49 m/s − 0 m/s
16 m/s2
T = 3.0625 s
Directions: Choose 4 or 5
4. It is n ow 10:29 a.m., but when the bell rings at 10:30 a.m. Suzette will be late for French class
for the third time this week. She must get from one side of the school to the other by hurrying
down three different hallways. She runs down the f irst hallway, a d istance of 65.0 m, at a s peed
of 5.2 m/s. The second hallway is filled with students, and she covers its 3 2.0 m length at an
average s peed of 1.46 m/s. The final hallway is empty, and Suzette sprints its 6 0.0 m length at a
speed of 7.3 m/s.
a. Does Suzette make it to class on time or does she get detention for being late again?
First Hallway:
T = D/V
T = 65 m/5.2 m/s
T = 12.5 s
Second Hallway:
T = D/V
T = 32 m/1.46 m/s
T = 21.9 s
Third Hallway:
T = D/V
T = 60 m/7.3 m/s
T = 8.2 s
Total Time: 12.5 s + 21.9 s + 8.2 s = 42.6 s
Suzy makes it to class on time
1. The tortoise and the hare are in a road race to defend the honor of their breed. The tortoise
crawls the entire 1000. m distance at a speed of 0.35 m/s while the rabbit runs the first 200.0
m at 1.85 m/s The rabbit then stops to take a nap for 1.200 hr and awakens to finish the last
800.0 m with an average speed of 4.2 m/s. Who wins the race and by how much time?
2. What is the Acceleration of the Cart on the Ramp? Determine the Angle of the Ramp (A).
Angle Chart: h ttps://drive.google.com/open?id=0B4RmhXJlHvo1YXZhcDNMSDNSMXc
1st Angle:
sin(x°) = opposite
hypotenuse
sin(x°) = 50 m
200 m
sin(x°) = 0.25
x° = 14.48°
2nd Angle:
sin(x°) = opposite
hypotenuse
sin(x°) = 100 m
200 m
sin(x°) = 0.5
x° = 30°
1st Angle Velocity Distance 1:
V = D/T
V = 100 m/10 s
V = 10 m/s
1st Angle Velocity Distance 2:
V = D/T
V = 100 m/5 s
V = 20 m/s
1st Angle Acceleration:
A= V2−V1
T
A= 20 m/s − 10 m/s
15 s
A= 10 m/s
15 s
A = 0.67 m/s2
2nd Angle Velocity Distance 1:
V = D/T
V = 100 m/5 s
V = 20 m/s
2nd Angle Velocity Distance 2:
V = D/T
V = 100 m/2 s
V = 50 m/s
2nd Angle Acceleration:
A= V2−V1
T
A= 50 m/s − 20 m/s
7s
Which Angle had the greatest Acceleration? Write a Conclusion based on your findings. Create
a Graph if you have time.
Height of
Ramp Velocity Velocity
2 Acceleration
(Opposite) Dist. 1 Time 1 1 Dist. 2 Time 2
50 m 100 m 10 sec. 10 m/s 100 m 5 sec. 20 m/s 0.67m/s2
100 m 100 m 5 sec. 20 m/s 100 m 2 sec. 50 m/s 4.29 m/s2
Graph:
Conclusion:
The purpose of the experiment was to find which angle of the ramp had the greatest acceleration.
As you can see from the data table, the 2nd angle that was 30° had the greatest acceleration, 4.29
m/s2, compared to the 1st angle that was 14.48° and had an acceleration of 0.67 m/s2 . The angles
were found by using the trigonometric sine ratio, opposite over hypotenuse, and then substituting
those values in. To find the velocity, the variables known, such as time and distance, made it
possible to calculate the it using the formula. From the velocities, the acceleration was found
through the acceleration formula. Because the amount of acceleration from angle 2 is clearly
greater than angle 1, the result of the two angles from the acceleration formula proved that the
2nd angle had a greater acceleration.
EXTRA CREDIT:
Light from the another star in the galaxy reaches the earth in 46 minutes. The speed of light is
3.0 × 108 m/s. In k ilometers, how far is the earth from the star?
D=V*T
D = 3 × 108 m/s × 2760 s
D = 8.28 × 101 1 m
D= 8.28 × 108 km
Answer must be in scientific notation
GPE Project
Potential
Energy Project
Due: Friday 3/17
Define and make note cards or QUIZLET for the following words:
Energy: Joules: Chemical Potential Law of Conservation
The capacity for A unit of Energy: of Energy:
doing work measurement for The energy stored in The rule that the total
energy, equal to the the chemical bonds energy of a system
work done by the of a substance remains constant
force of one newton
when an object
moves one meter
Kinetic Energy: Kilojoules: Elastic Potential Gravity:
Energy that a A unit of Energy: A force in which all
physical being has measurement The potential energy objects with mass are
when in motion equivalent to one stored inside the brought towards
thousand joules deformation of an something (such as a
elastic object planet)
Potential Energy: the Gravitational Mechanical Energy:
stored energy of Potential Energy: The sum of potential
position possessed The potential energy and kinetic energy,
by an object an object possesses associated with the
from its position in motion and position
the gravitational field of an object
Resource: h ttp://www.physicsclassroom.com/class/energy/Lesson-1/Potential-Energy
Gravitational Potential Energy
Determine the Gravitational Potential Energy (GPE) of different gravities (m/s2 ) of
different planets
Planets: Florrum, Coruscant, Naboo, and Corellia
4 objects: Katrina, Amy, Tobias, and Aly
Total Mass: 197.766 kg
*2.2 lbs = 1 kg
Data Table:
Your data table will need: Object, mass, gravity, height, GPE
Videos: http://www.youtube.com/watch?v=x5JeLiSBqQY
*Video shows you how to use the GPE equation.
Determine the GPE of one of the masses on the following planets:
Coruscant- 17% greater than Earth’s Gravity
Gravity:
1.17 × 9.807 m/s2
11.474 m/s2
Corellia- 39% less than Earth’s Gravity
Gravity:
1.00 - 0.39 = 0.61
0.61 × 9.807 m/s2
5.98 m/s2
Naboo - 82% greater than Earth’s Gravity
Gravity:
1.82 × 9.807 m/s2
17.849 m/s2
Florrum- 48% less than Earth’s Gravity
Gravity:
1 - 0.48 = 0.52
0.52 × 9.807 m/s2
5.107 m/s2
*Use the height of your favorite Roller Coaster. You will use this to figure out the
Velocity at the bottom of the hill on the Star Wars Planets.
Rollercoaster: Wicked Cyclone
Height: 33 m
Calculations:
Choose 3 planets from the Star Wars Universe
Coruscant
GPE = KE
m × g × h = 0.5mv2
(197.766 kg)(11.474 m/s2 )(33 m) = 0.5(197.766 kg)v2
74,882.51 = 98.88v2
v2 = 757.28
√ v2 = √ 757.28
v = 27.52 m/s
Naboo
GPE = KE
m × g × h = 0.5mv2
(197.766 kg)(17.849 m/s2 )(33 m) = 0.5(197.766 kg)v2
116,399.16 = 98.88v2
v2 = 1,177.18
√ v2 = √ 1,177.18
v = 34.31 m/s
Florrum
GPE = KE
m × g × h = 0.5mv2
(197.766 kg)(5.107 m/s2 ) (33 m) = 0.5( 197.766 kg)v2
33,329.7 = 98.88v2
v2 = 337
√ v2 = √ 337
v = 18.4 m/s
Corellia
GPE = KE
m × g × h = 0.5mv2
(197.766 kg)(5.98 m/s2) (33 m) = 0.5(197.766 kg)v2
38,505.04 = 98.88v2
v2 = 389.4
√ v2 = √ 389.4
v = 19.73 m/s
Data Table:
Graph:
X - axis: Planet
Y -axis: Potential Energy
Critical Thinking Questions:
1. What factors affect Gravitational Potential Energy?
a. The factors that affect GPE are height, mass, and gravity
2. Why did the GPE change on the other planets?
a. The GPE changed on other planets because even though the height and mass
were the same in the calculations, every planet had their own unique gravity so
they all resulted in different answers
3. Which planet would you be able to hit a golf ball further? Explain using data.
a. On the planet Naboo you would be able to hit a golf ball furthest because its GPE
is the greatest out of the other three, which therefore contributes to its high
velocity. So if you hit a golf ball, the high velocity would make the ball go faster,
and as a result, a longer distance
4. How does GPE relate to Chemical Potential Energy?
a. GPE relates to Chemical Potential Energy because they are both types of
potential energy. GPE is the amount of potential energy an object has based on
its area/position in the gravitational field, while Chemical Potential Energy is the
amount potential energy stored inside chemical bonds. Even though they relate
to different factors, they are all about the stored energy that an object is able to
have
5. How do Energy companies use GPE to generate Electrical Energy? Give an example
a. Energy companies use GPE to generate electrical energy because the energy
can be converted into kinetic energy, which is the energy given off in movement
and therefore gives off enough work to generate Electrical energy. For example,
the Hoover Dam uses the conversion of GPE to kinetic energy and harnesses the
work created to give power to people in the US. With each passing second, the
potential energy in the waters of Lake Mead are increasing, until the water
cascades down the spillways. When the water is falling down, the potential
energy becomes kinetic, and as the water rushes down the intake towers,
hydroelectric generators pick up all the force that is created and turns that into
electric energy. Because the conversion of potential energy to kinetic energy is
enough to generate electrical energy, that is how energy companies use GPE to
power people’s homes and buildings.
6. What happens to the GPE when the object falls to the ground? Describe the Energy
transformations along the way. Use a diagram.
a. When an object is falling to the ground, the GPE is being transformed into kinetic
energy. From the beginning, at the highest point, that is where the object has the
most GPE, enough ability to create force to move. After the GPE has reached the
maximum point, that is where it begins to break in, and all that GPE gained starts
to move the object. Because it is beginning to physically move, it shows that the
GPE is being converted into kinetic energy, so GPE is decreasing while kinetic
energy is increasing. Due to the Law of Conservation of Energy, the kinetic
energy too will eventually reach a point where it dwindles, also affected by the
force of friction, and this slows the object down. As a result, the GPE will start
gaining once again, and the cycle repeats.
Worksheet 1:
http://glencoe.mheducation.com/sites/0078600510/student_view0/unit1/chapter4/math_practice_2.html
Worksheet 2: h ttp://go.hrw.com/resources/go_sc/ssp/HK1MSW65.PDF
*We will use our information to see how a roller coaster would be different on those planets.
FINAL PART - Roller Coaster Physics
Objective:
1. When energy is transformed, the total amount of energy stays constant (is conserved).
2. Work is done to lift an object, giving it gravitational potential energy (weight x height). The
gravitational potential energy of an object moving down a hill is transformed into kinetic
energy as it moves, reaching maximum kinetic energy at the bottom of the hill.
Determine the velocity of a full roller coaster of riders at the bottom of the largest hill. You can
use the following roller coasters:
Watch these Videos for help:
http://www.youtube.com/watch?v=Je8nT93dxGg
http://www.youtube.com/watch?v=iYEWIuQBVyg
Use either:
GPEtop = KEbottom
Formula: GPEtop = KEbottom
GPE Data Table
Planet GPE (J) Velocity (m/s)
Corellia 38,505.04 19.73
Florrum 33,329.70 18.4
Coruscant 74,882.51 27.52
Naboo 116,399.16 34.31
GPE Presentation
https://docs.google.com/presentation/d/10rmOfK6pl1WdG4CFQudA3s_
2PE5_CJetn2u7Noyfcnc/edit?usp=sharing
Pendulum Gravity Experiment
Data Table
string average for 10 average for 1 gravity average
length gravity % Error
trial 1 trial 2 Trial 3 oscillations oscillation (m/s2)
0.83 m 18.61 s 19.13 s 18.84 s 18.86 s 1.886 s 8.88 9%
9.2 m/s2 m/s2
0.5 m 14.41 s 14.42 s 14.37 s 14.42 s 1.442 s 9.49 8.88 9%
m/s2 m/s2
0.3 m 12.46 s 12.30 s 11.82 s 12.193 s 1.219 s 8.88 9%
7.95 m/s m/s2
Quiz Review: GPE
1. Suppose you placed a 230 kg Siberian Tiger on the Superman Roller Coaster
on the planet Tatooine. This roller coaster has a height of 125 m and Tatooine
has a gravity that is equal to 23% greater than that of Earth’s. What would be
your velocity at the bottom of the hill?
a. Gravity: 1.23 × 9.807 = 12.06 m/s2
b. GPE = KE
c. m × g × h = 0.5mv2
d. (230 kg)(12.06 m/s2)(125 m) = 0.5(230 kg)v2 .
e. 115v2 = 346,725
f. v2 = 3015
g. v = 54.9 m/s
2. In 1993, Cuban athlete Javier Sotomayor set the world record for the high
jump. The gravitational potential energy associated with Sotomayor’s jump
was 2130 J. Sotomayor’s mass was 89.0 kg. How high did Sotomayor jump?
a. GPE = m × g × h
b. (89 kg)(9,807 m/s2 )h = 2130
c. 872.823h = 2130
d. h = 2.44 m
3. One of the tallest radio towers is in Fargo, North Dakota. The tower is 629 m
tall, or about 44 percent taller than the Sears Tower in Chicago. If a bird lands
on top of the tower, so that the gravitational potential energy associated with
the bird is 1250 J, what is its mass?
a. GPE = m × g × h
b. m(9.807 m/s2 )(629 m) = 1250
c. 6168.603m = 1250
d. m = 0.2 kg
4. With an elevation of 5334 m above sea level, the village of Aucanquilca, Chile
is the highest inhabited town in the world. What would be the gravitational
potential energy associated with a 95 kg person in Aucanquilca?
a. GPE = m × g × h
b. (95 kg)(9.807 m/s2 )(5334 m) = GPE
c. GPE = 4,969,501
Quiz Review 2: GPE
Scenario: You are an engineer for a major engineering firm that will design the lift motor and
safety restraints for the next roller coaster on the planet Naboo in Star Wars. Naboo has a
gravity equal to 64% greater than Earth’s. The Star Wars Theme Park needs to provide you
with the velocity of the roller coaster on this planet to help you with your design. Your roller
coaster will be called the Millenium Falcon and will have a height of 83 m. YOur roller coaster
will “The Falcon” will have a mass of 3,400 kg. You will need to compare the needs for safety
on Earth to the needs on Naboo. Explain your reasoning for the changes on Naboo.
Naboo:
Directions: Provide a data table showing the comparisons between the Millenium Falcon Roller
Coaster on Earth and Naboo. Describe the types of restraints that you would need on the faster
coaster.
Calculations:
Earth Naboo
GPE = KE Gravity: 64% greater than Earth’s
m × g × h = 0.5mv2 Gravity: 1.64 × 9.807 m/s2 = 16.08 m/s2
(3,400 kg)(9.807 m/s2 )(83 m) = 0.5(3,400kg)v2 GPE = KE
1,700v2 = 2,767,535.4 m × g × h = 0.5mv2
v2 = 1627.96
(3,400 kg)(16.08 m/s2 ) (83 m) = 0.5(3,400kg)v2
v ≈ 40.35 m/s 1,700v2 = 4,537,776
v2 = 2669.28
v ≈ 51.67 m/s
Data Table:
Planet Gravity (m/s2) Velocity (m/s)
Earth
Naboo 9.807 40.35
Graph: 16.08 51.67
Conclusion:
As you can see from the data table and graph, the Millenium Falcon would have a velocity of
40.35 m/s if it was built on Earth, and a velocity of 51.67 m/s on Naboo. Therefore, the
rollercoaster on Naboo would need special restraints to ensure the safety of the ride/.
Extra Problems:
1. The Millenium Falcon Roller Coaster has a mass of 8500 kg on Planet Tatooine.
The height of the roller coaster is 125 m which results in a Potential Energy of
750,000 J. What is the gravity on Planet Tatooine?
GPE = m × g × h
750,000 = (8,500 kg) × g × (125 m)
1,062,500g = 750,000
g ≈ 0.71 m/s2
2. The Tie Fighter Roller Coaster has a height of 115 m. on Planet Hoth. Hoth has
a gravity of 13.2 m/s2 . This roller coaster has a Potential Energy of 450,000 J. What is the
mass of the Tie Fighter?
GPE = m × g × h
450,000 = m × (13.2 m/s2 ) × (115 m)
1,518m = 450,000
m ≈ 296.44 kg
Quiz: GPE/KE
Scenario: You are an engineer for a major engineering firm that will design the lift motor and
safety restraints for the next roller coaster on the planet Hoth in Star Wars. H oth has a gravity
equal to 37% greater than Earth’s. The Star Wars Theme Park needs to provide you with the
velocity of the roller coaster on this planet to help you with your design. Your roller coaster will
be called the Millenium Falcon and will have a height of 125 m. Your roller coaster will “The
Falcon” will have a m ass of 7000 kg. You will need to compare the needs for safety on Earth to
the needs on Hoth. Explain your reasoning for the changes on Hoth.
Hoth:
Directions: Provide a data table showing the comparisons between the Millenium Falcon Roller
Coaster on Earth and Hoth. Describe the types of restraints that you would need on the faster
coaster.
Calculations: Hoth
Earth Hoth
Earth Gravity:
Gravity: 9.807 m/s2 37% greater than Earth’s
GPE = KE
mgh = 0.5mv2 1.37 9.807 m/s2 13.44 m/s2
(7000 kg) (9.807 m/s2) (125 m) = 0.5(7000
kg)v2 GPE = KE
3500v2 = 8,581,125 J
v2 = 2451.75 mgh = 0.5mv2
v2 = 2451.75
v 49.52 m/s (7000 kg) (13.44 m/s2 ) (125 m) = 0.5(7000
kg)v2
3500v2 = 11,760,000 J
v2 = 3360
v2 = 3360
v 57.97 m/s
Data Table: GPE Velocity
Planet 11,760,000 57.97
Hoth 49.52
Earth 8,581,125
Graph:
Conclusion:
In conclusion, from the calculations and data table shown above, the planet Hoth would have a
greater velocity for the Millenium Falcon compared to Earth, because it has a velocity of 57.97 m/s while
Earth only has a velocity of 49.52 m/s. Because the gravitational potential energy (GPE) created during a
rollercoaster ride is equivalent to the kinetic energy that will be produced, the equation GPE = KE is true.
GPE = KE is also equal to mgh = 0.5mv2 , because mass, gravity, and height are influential factors in the
GPE and kinetic energy is a telltale mark of the speed, aka velocity. Substituting the variables that are known
in the equation for Hoth, such as the mass (7000 kg), gravity (13.44 m/s2, from calculating), and height (125
m), the outcome will be a velocity of 57.97 m/s. The same steps were repeated to calculate the velocity for
Earth, plugging in the mass (7000 kg), gravity (9.807 m/s2 ) , and height (125 m), in the same equation and
getting an answer of 49.52 m/s. From the calculations above, it is important to note that the gravity of the
two planets is the only factor that really changes and affects the outcome of the velocity, so gravity is an
independent variable and velocity is the dependent variable. Because Hoth’s velocity for the Millenium Falcon
would be greater, some possible preventive measures to ensure the safety of the ride would be: to have longer
tracks (to spread out the kinetic energy that generates after the conversion of potential energy), a smaller hill
so less potential energy will be created, and as a result, less kinetic energy so the rollercoaster will be slower,
and maybe special tracks that create more friction when the rollercoaster slides across them to slow it down.
In the end, those are the measures that need to be taken if the Millenium Falcon is built on both planets.
Extra Problems:
1. The Millenium Falcon Roller Coaster has a mass of 3200 kg on Planet Tatooine.
The height of the roller coaster is 15 m which results in a Potential Energy of
800,000 J. What is the gravity on Planet Tatooine?
a. GPE = mgh
b. 800,000 = (3200 kg)g(15 m)
c. 48,000g = 800,000
d. g = 16.7 m/s2
2. The Tie Fighter Roller Coaster has a height of 150 m. on Planet Hoth. Hoth has a
gravity of 5.2 m/s2. This roller coaster has a Potential Energy of 600,000 J. What
is the mass of the Tie Fighter?
a. GPE = mgh
b. 600,000 = m(5.2 m/s2)(150 m)
c. 780m = 600,000
d. m = 769.2 kg
Quarter 4
Quarter 4 Contents
Simple Machines Presentation
Inclined Planes Practice Problem
Quiz Review: Inclined Planes
Quiz: Inclined Plane 2018
Height of Tree Poster/Practice Problem
Tree Height Practice 2
Heat Project
Specific Heat Practice Problem
Specific Heat Lab
Electricity Timeline Poster
Building Series/Parallel Circuits
Simple Machines Presentation
https://docs.google.com/presentation/d/1NZoDaJxTq89QfUXE8GCd2g
kLkNltYzHZfpFviMDuegs/edit?usp=sharing
Inclined Planes Practice Problem
Scenario: Suppose you would like to bring a 175 N box up to a height of 29 m. You decide to
use an inclined plane because you just learned about them in science class. The ramp you
design has a distance of 48 m. You also measure the Force (N) needed to push the box up the
ramp which is 85 N. What is the Work Output, Work Input, Ideal Mechanical Advantage, Actual
Mechanical Advantage, and Efficiency of the machine?
*Use your notes
Work Output = Force × Output Distance
Work Output = 85 × 29
Work Output = 2465 N
Work Input = Force × Input Distance
Work Input = 85 × 48
Work Input = 4080 N
A. Use “Drawing” to label a triangle (Inclined Plane)
B. Calculate the angle of the ramp.
sin- 1(x°) = 29
48
x ≈ 37°
C. Calculate the Ideal Mechanical Advantage (IMA)
IMA = Input Distance/Output Distance
IMA = 48
29
IMA ≈ 1.66
D. Calculate the Actual Mechanical Advantage (AMA)
AMA = Output Force/Input Force
AMA = 2465
4080
AMA = 0.60
E. Calculate the Efficiency (%)
Efficiency = Work output/Work input * 100
Efficiency = 2465 × 100
4080
Efficiency = 60%
Questions:
1. Is this machine possible? Explain using evidence from the problem.
a. This inclined plane is possible because the efficiency of the machine is 60% as
calculated, meaning it is under 100% efficiency and follows the laws of friction
and motion, so therefore it is performable.
2. How could you change the Input Force or Distance or to make it possible?
a. The machine is already possible, but if it wasn’t, and had an efficiency 100% or
over, you can increase the Input Force and Input Distance to become greater
than the Work Output in the Efficiency Formula, so with the greater value on the
denominator of the formula, it will end up with a percentage smaller than 100%,
so the machine can be possible.
3. How would this problem be different on another planet?
This problem could be different on another planet because the laws of physics
might differ from ours, for example, maybe a machine over 100% efficiency could
be possible on that planet, or work won’t equal force times distance. This could greatly change
the overall characteristics of the problem.
Quiz Review: Inclined Plane
Directions: Analyze the Inclined Plane Data Table that is shared on
Classroom and determine which machine has the greatest Actual
Mechanical Advantage (AMA).
Problem Statement:
How does the angle of an inclined plane affect the Mechanical
Advantage? Is there a machine that is impossible? Explain using
data.
Hypothesis: (Use proper form!)
If the angle of the inclined plane is the greatest, then the Mechanical Advantage will
also be the greatest. Additionally, if a machine exceeds an efficiency of a hundred
percent, then that would be impossible because that would violate the properties of
friction.
Diagrams of Inclined Planes: (Use DRAWING - Label Diagrams)
sin(x)-1 = 30 sin(x)- 1 = 30 sin(x)-1 = 30
150 90 40
≈ 11.54 ≈ 19.47
≈ 48.59
Angle Chart: h ttps://drive.google.com/open?id=0B4RmhXJlHvo1YXZhcDNMSDNSMXc
Calculations (Examples):
IMA = 150 AMA = 7 Efficiency = 210 × 100
30 2 300
=5 = 3.5 = 70%
IMA = 90 AMA = 7 Efficiency = 210 × 100
30 3 270
=3 = 2.3 = 78%
IMA = 40 AMA = 7 Efficiency = 210 × 100
30 4 160
= 1.33 = 1.75 = 131%
Data Table:
Angle IMA AMA Efficiency%
12 5 4 70
19 3 2 78
49 1 2 131
Link:
https://docs.google.com/spreadsheets/d/1xleZY6wDjnYV4to26sP-PMk
yGpLQM6bERhfS8owi1Oc/edit#gid=1590054886
Graph: (Angle and Mechanical Advantage)
Conclusion:
Option #1 Write a Conclusion.
***Your conclusion must also address which machine would be impossible
and why?
1. Discuss purpose
2. Restate hypothesis - angle and mechanical advantage
3. Data to support hypothesis
4. Is there a machine that is impossible? Explain using research on
the Law of Conservation of Energy (Support with research - Use
Explore Tool research - INLINE CITATIONS )
5. Use this source to explain the relationship of this machine to
Newton’s First Law of Motion.
The purpose of the experiment was to test the Mechanical Advantage
and Efficiency of three different angles of inclined planes, and see which
had the greatest AMA. The hypothesis was that if the angle of the inclined
plane is the greatest, then the Mechanical Advantage will also be the
greatest. Additionally, if a machine exceeds an efficiency of a hundred
percent, then that would be impossible because that would violate the
properties of friction. From the results of the experiment, the opposite was
actually true. For example, the inclined plane with the greatest angle of 49°
had a AMA of 2, while the smallest angle, 12°, had a AMA of 4, which is
double the amount of the inclined plane with the greatest angle. Machines
cannot be impossible (having an efficiency being or exceeding 100%). This
is shown by the Law of Conservation of Energy, which states in a simplified
form: “you can’t create or destroy energy, but you can convert it from one
form into another” (explainthatstuff.) A machine can never be impossible
because all the energy that is produced is always being converted into
other forms to perform work. The relationship of an inclined plane to
Newton’s First Law of Motion is that they all obey and follow the law. The
law states: “An object at rest stays at rest and an object in motion stays in
motion with the same speed and in the same direction unless acted upon
by an unbalanced force” (physicsclassroom.) This corresponds with
inclined planes, because they can’t perform any work until an “unbalanced
force,” (such as a person pushing up an object on them), acts upon it. In
conclusion, an inclined plane with the least angle degree will have the
greatest AMA, a machine cannot be impossible due to the Law of
Conservation of Energy, and the relationship of inclined planes to Newton’s
First Law of Mass is that they always follow that law.
Citations
http://www.explainthatstuff.com/conservation-of-energy.html
http://www.physicsclassroom.com/class/newtlaws/Lesson-1/Newton-s-First
-Law
Quiz: Inclined Plane 2018
Directions: A nalyze the Inclined Plane Data Table that is shared on
Classroom and determine which machine has the greatest Actual
Mechanical Advantage (AMA).
Problem Statement:
How does the angle of an inclined plane affect the Mechanical
Advantage? Is there a machine that is impossible? Explain using
data.
Hypothesis: ( Use proper form!)
If the angle of an inclined plane is greater, then the resulting Mechanical Advantage will
also be greater. If a machine’s efficiency exceeds 100%, then that machine will be
impossible because that would violate the Law of Conservation of Energy.
Diagrams of Inclined Planes: (Use DRAWING - Label Diagrams)
Angle: Output Distance Angle: Output Distance
Input Distance Input Distance
sin(x)- 1 = sin(x)-1 =
sin(x)-1 = 70 sin(x)-1 = 70
300 100
≈ 13.49° ≈ 44.43°
Angle Chart: https://drive.google.com/open?id=0B4RmhXJlHvo1YXZhcDNMSDNSMXc
Calculations ( Examples):
IMA = Input Distance AMA = Output F orce Efficiency = W ork Output × 100
Output Distance Input F orce W ork Input
300 12 840 × 100
IMA = 70 AMA = 4 Efficiency = 1200
IMA = 4 .29 AMA = 3 Efficiency = 70%
IMA = Input Distance AMA = Output F orce Efficiency = W ork Output × 100
Output Distance Input F orce W ork Input
100 12 840 × 100
IMA = 70 AMA = 8 Efficiency = 800
IMA = 1 .43 AMA = 1 .5 Efficiency = 105%
Data Table: ( Located on Google Classroom)
Angle Ideal Mechanical Actual Mechanical Advantage Efficiency
Advantage 4 3 70%
1 2 105%
13
44
Graph: (Angle and Mechanical Advantage)
Research:
***Your conclusion must also address which machine would be impossible
and why?
Research:
An impossible machine, any machine that is or exceeds 100% efficiency, would
not exist because it outlaws the Law of Conservation of Energy and won’t function as
a machine should. The Law states: “In a closed system, the amount of energy is fixed.
You can’t create any more energy inside the system or destroy any of the energy
that’s already in there. But you can convert the energy you have from one form to the
other (and sometimes back again)” (explainthatstuff.) So during the process of work,
the amount of energy is always being transformed and converted into other types of
energy. Because of physics and the way a machine functions, the energy a machine
starts out with will eventually succumb to certain factors, such as friction and heat. In
order for the machine to keep doing work, the energy will be converted into different
types to overpower those factors. For example, “If a car were 100 percent efficient, all
the chemical energy originally locked inside the gasoline would be converted into
kinetic energy. Unfortunately, energy is wasted at each stage of this process. Some is
lost to friction when metal parts rub and wear against one another and heat up; some
energy is lost as sound.” As a result, machines will never be 100% efficient, so it rules
out the idea if machines can be impossible.
The relationship of inclined planes to Newton’s First Law of Motion is that their
performance always follows that Law. The Law states: “An object at rest stays at rest
and an object in motion stays in motion with the same speed and in the same
direction unless acted upon by an unbalanced force” (physicsclassroom.) An inclined
plane can never do its job unless something or someone acts upon it with an unequal
force, like a person pushing a barrel up to it. That changes the inclined plane’s state
and causes it to do its work. Because an inclined plane evidently follows Newton’s
First Law of Motion, that is the most obvious relationship.
Sources:
http://www.explainthatstuff.com/conservation-of-energy.html
http://www.physicsclassroom.com/class/newtlaws/Lesson-1/Newton-s-First-Law
Height of Tree Poster/Practice Problem
Activity: Determine Height of Tree and Inclined Plane Poster
Angle Chart: h ttps://drive.google.com/open?id=0B4RmhXJlHvo1YXZhcDNMSDNSMXc
1. Use your Clinometer to determine the angle to the tree.
Test 1 Angle: 3 5°
Test 1 Opposite: 15.5 m
Test 2 Angle: 20°
Test 2 Opposite: 13 m
2. Follow the steps on this site”
http://www.instructables.com/id/Using-a-clinometer-to-measure-height/
Do this with your partner.
3. Determine the length of the hypotenuse using pythagorean theorem.
Do this with your group.
Test 1:
sin(35°) = 15.5
hypotenuse
Hypotenuse = 15.5
sin(35°)
Hypotenuse ≈ 27.02 m
Test 2:
sin(20°) = 13
hypotenuse
Hypotenuse = 13
sin(20°)
Hypotenuse ≈ 38.01 m
4. How can you design an inclined plane to get to the top of your tree or foul pole?
You can design an inclined plane to get to the top of a tree or foul pole by finding the
angle from the ground to the top of the tree or foul pole by a clinometer. Using this given angle,
the trigonometric functions of sin and tangent should be utilized to find the distance from the
angle to the tree/foul pole (the adjacent side of the inclined plane), the distance from the angle
to the top of the tree/foul pole (the hypotenuse of the inclined plane), and the height of the
tree/foul pole (the opposite side of the inclined plane). From the given angle and distances, an
inclined plane can be constructed to get to the top of a tree/foul pole.
Force output: 125 N
IMA: Calculate this
Test 1:
IMA = hypotenuse
opposite
IMA = 27.02
15.5
IMA ≈ 1.74
Test 2:
IMA = 38.01
13
IMA ≈ 2.92
AMA: Use 42% less than the IMA
Test 1:
AMA = 0.58 × 1.74
AMA ≈ 1.01
Test 2:
AMA = 0.58 × 2.92
AMA ≈ 1.69
Make poster showing this calculation.
Extra Credit: Use 2 different angles
Tree Height Practice 2
Determine the height of the trees in the following examples. You will also need to calculate the
IMA and AMA using the given information.
Make Diagrams and calculate in Notebook first
Example 1: A student walked 43 meters away from the tree and measured the angle through
the clinometer to the top of the tree to be 18 degrees.
1. What is the height of the tree?
a. tan(18) = x
43
b. x = 43 × tan(18)
c. x ≈ 13.97 m
2. What is the Input Distance to the top of the tree?
a. sin(18) = 13.97
h
13.97
b. h= sin(18)
c. h ≈ 45.21 m
3. What is the IMA?
a. IMA = h
x
45.21
b. IMA = 13.97
c. IMA ≈ 3.24
4. The AMA is 27% less than the IMA. What is the AMA?
a. AMA = 0.73 × IMA
b. AMA = 0.73 × 3.24
c. AMA ≈ 2.37
5. The Output Force is 350 N.
6. What is the Input Force?
a. Input Force = Output F orce
AM A
350
b. Input Force = 2.37
c. Input Force ≈ 147.68
Example 2: A student walked 84 meters away from the tree and measured the angle through
the clinometer to the top of the tree to be 29 degrees.
7. What is the height of the tree?
a. tan(29) = x
84
b. x = 84 × tan(29)
c. x ≈ 46.56 m
8. What is the Input Distance to the top of the tree?
a. sin(29) = 46.56
h
46.56
b. h= sin(29)
c. h ≈ 96.04 m
9. What is the IMA?
a. IMA = h
x
96.04
b. IMA = 46.56
c. IMA ≈ 2.06
10. The AMA is 42% less than the IMA. What is the AMA?
a. AMA = 0.58 × IMA
b. AMA = 0.58 × 2.06
c. AMA ≈ 1.2
11. The Output Force is 75 N.
12. What is the Input Force?
a. Input Force = Output F orce
AM A
75
b. Input Force = 1.2
c. Input Force ≈ 62.5
Heat Project
Thermal (Heat) Energy Project
Chapter 6 (pg. 156-180)
DUE: Monday May 21st
1. Vocabulary - Define and make note cards or quizlet
Conduction: a Heat: a form of Insulator: blocks Calorie: a unit of
transfer of heat by energy related to the flow of energy. heat and energy
particle collisions the movement of A perfect insulator equal to raise 1
and movement of atoms does not exist gram of water by 1
electrons ℃
Convection: heat is Temperature: Second Law of Turbine: a machine
transferred by the measure of the Thermodynamics: generating
movement of fluids average kinetic when energy is continuous power
energy of particles transferred from the by revolving around
in a system cold object to the fluids
hot object
Radiation: emission Heat Engine: a Specific Heat: the Generator: a
of energy as device for heat required to machine that
electromagnetic generating motive raise the converts one form
waves or subatomic power from heat temperature of a of energy to
particles substance by a another
given degree
First Law of Conductor: An Kinetic Energy:
Thermodynamics: object which allows energy that is
Heat energy cannot electric currents to generated when an
be created nor pass through it object is in motion
destroyed, but can
be transferred from
one location to
another and
converted into other
forms of energy
2. Provide a diagram showing molecular motion in Solids, Liquids, and gases.
*How are they different?
As you can see from the picture, in solids, all the molecules are packed and
compressed together, in liquids, they are mobile, and in gases, they are completely
independent from each other.
3. Discuss the energy needed to change a 15 gram ice cube into steam. Use a
graph and one calculation from our unit on Phase Changes.
Heat = 15g × 333.6 J/g
Heat = 5004 J
Heat = 15g × (100 - 0)C × 4.178 J/g C
Heat = 15g × 100 C × 4.178 J/g C
Heat = 6267 J
Heat = 15g × 2257 J/g
Heat = 33,855 J or 3.3855 × 104 J
As you can see, from the process of melting the ice cube (Heat of Fusion), it
would be represented as the mass of the ice cube times the Heat of Fusion for water,
which is 15 grams times 333.6 joules per gram. The result would be 5,004 joules. To
heat it up to the boiling point, the equation is the mass of the ice cube, 15 grams, times
the change in the starting temperature and final temperature, 100 C - 0 C = 100 C,
times the specific heat of water. This leads to an answer of 6267 joules. Finally, turning
it into steam (Heat of Vaporization), the mass of the ice cube, 15 grams, would be
multiplied by the Heat of Vaporization for water; in this case, it is 2257 joules per gram.
Therefore, this leads to 33,855 joules in total, which is the overall amount of energy
needed to convert a 15 gram ice cube to steam.
4. What is the difference between Heat and Temperature? Provide a definition,
picture and video link to help you review.
Heat is form of energy from the movement of atoms while temperature is a
measure of the average kinetic energy in a system. For example, there can be two
beakers of different volumes having the same temperature, but they will have different
amounts of heat energy because it
took more work to raise the
temperature of a beaker with a
larger volume than a beaker with a
smaller volume.
Video:
https://www.youtube.com/watch?v=zf_6fpNbaR0
5. Construct a graph showing the average monthly temperatures in Hartford, CT.,
a city on the equator and a city in the Southern Hemisphere.
Questions:
1. What do you notice about the temperatures?
a. In Hartford, USA, the temperatures get warmer throughout the summer
and colder throughout the winter. In Sydney, Australia, the temperatures
get colder throughout the summer and warmer throughout the winter. In
Pontianak, Indonesia, the temperature is constant throughout no matter
the season.
2. How is heat transferred throughout the Earth?
a. As you can see from the graph, the farther away a location is from the
equator, the more temperature fluctuations it will have. Additionally, places
in the northern hemisphere are generally colder in the winter and warmer
in the summer, and vice versa for places in the southern hemisphere.
4. How is Steam used to create electricity in Power Plants?
A. Coal Plant
When water is heated into steam, it turns a turbine which powers an electric
generator. This produces the electricity we use day to day.
B. Natural Gas Plant
The energy is created mostly inside a gas turbine, where gas is ignited to make
high-temperature combustion heat, which turns the turbine and produces electricity from
the generator connected to it.
C. Nuclear Plant
In a nuclear plant, energy is produced by splitting atoms inside nuclear reactors,
heating up the water in the reactor until it vaporizes into steam. In turn, the steam
moves a turbine which powers a generator, creating electricity.
D. Where did Fossil Fuels originate?
Fossil fuels formed millions of years ago from the decomposition of ancient
organisms.
E. What is the difference between Renewable and NonRenewable forms of energy?
Renewable energy is electricity conceived from recyclable matter that can be
replenished through time. Non-renewable energy, on the other hand, is electricity that is
made from resources that won’t ever be replaced again. Because of their
characteristics, renewable energy is much more efficient.
Part II - Water, Orange Juice and Vegetable Oil
1. Conduct an experiment to determine the Heat Gained by 20 g of each substance
2. You must measure the mass of Orange Juice and Vegetable Oil.
3. Research the Specific Heats of Orange Juice and Vegetable Oil in Calories/g C not in
Joules.
4. Make a data table
5. Construct a 3 Line graph for 2 minutes of data collection - 1 pt every 10 seconds
6. Write a conclusion about your results.
Data Table
Water Alcohol
time (minutes) Temperature Temperature
0 80 80
0.5 78 80
1 76 78
1.5 75 76
2 73 75
2.5 72 74
3 71 72
3.5 69 71
4 67 70
4.5 66 69
5 65 68
5.5 64 68
6 62 67
6.5 61 66
7 60 64
7.5 59 63
8 58 62.5
8.5 58 62
9 57 61
9.5 56 60
10 55 58.5
Graph
Critical Thinking Questions
1. What happens to the molecules in each of the beakers as heat is added?
As heat is slowly added, the molecules retain more and more energy, causing
them to move at a greater speed and break away the atomic attraction they normally
have at lower temperatures.
2. Which substance showed the greatest temperature change? Least? Use data
Water showed the greatest temperature change, while alcohol showed the least.
From the graph, both substances start out with the same temperature of 80 C, but
eventually the water ends up having a lower final temperature of 55 C compared to
alcohol’s final temperature of 58 C. Both cooled down in the same duration, so this
suggests that water has a fasting cooling rate than alcohol, and thus a greater
temperature change.
3. Which substance does research say should show the greatest temperature
decrease? Least? Why? How does this relate to Specific Heat?
As stated above, water has the greatest temperature change, or decrease, and
alcohol had the least temperature change/decrease. This relates to Specific Heat
because it can be assumed that the specific heat of a substance correlates with
temperature change. Water, as it is known, has a greater specific heat than other
substances like alcohol, so it takes more energy to raise it up one degree C. As a result,
it can be hypothesized that water is less able to retain heat than alcohol and will lose
heat faster.
4. How does Average Kinetic Energy relate to this experiment?
Average Kinetic Energy relates to this experiment because as the amount of heat
added to a substance increases, the kinetic energy of the molecules inside that
substance will also increase. Since the amount of heat will directly correlate with the
amount of kinetic energy, kinetic energy is related to the experiment.
5. Why is water a great substance to put into a car engine radiator?
Water is a great substance to use inside car engine radiators because water has
a greater specific heat compared to other compounds, which will make it harder to heat
up. When using a car, a lot of energy is produced, which gives off heat, so by utilizing
water, the heat is more efficiently absorbed and there will be less of a probability for the
car to suffer damages from overheating.
Practice Calculation
1. How much heat was gained by a 50 g sample of Orange Juice that increased its
temperature from 35 C to 75 C?
Heat Gain = Mass × ΔT × specific heat
Heat Gain = 0.05 kg × (75 C - 35 C) × 0.89 Kcal/kg
Heat Gain = 0.05 kg × 40 C × 0.89 Kcal/kg
Heat Gain = 1780 cal
2. How much heat was gained by a 350 g sample of Vegetable oil that increased
its temperature from 24 C to 95 C?
Heat Gain = Mass × ΔT × specific heat
Heat Gain = 0.35 kg × (95 C - 24 C) × 0.4 Kcal/kg
Heat Gain = 0.35 kg × 71 C × 0.4 Kcal/kg
Heat Gain = 9940 cal
Lopez Lab
Water (32 - 23) Oil (39-23)
http://www.kentchemistry.com/links/Energy/SpecificHeat.htm
Use this to help solve problems
6. Lab Experiment:
*Conduct an experiment that tests 3 different cups for their ability to insulate.
A. Conduct experiment
B. Create Data Table - Include Specific Heat
C. Write short conclusion paragraph that relates your data to research about the
effectiveness of the 3 materials to provide insulation.
Critical Thinking - Choose 2 out of 3 to research
Provide pictures
1. How did NASA protect the astronauts in their space vehicles from the harmful
radiation from space?
2. How is your home insulated? Research the “R” value system for insulation.
A house is insulated by using insulation materials, such as cellulose, fiberglass,
and mineral wool to reduce heat gain from conduction, convection and radiation.
Conduction is the flow of heat from one material to another, convection is the circulation
of heat, and radiation is the emission of energy waves through materials. In the winter,
heat from the interior of the house can flow to the outside, and likewise, in the summer
heat from the outside can travel to the interior. By reducing heat gain, a house can keep
a comfortable temperature year-long. Insulation can measured by how efficient it is at
resisting heat, which is called the R-value system. The higher the R-value is, the better
a material is at insulating.
https://www.energy.gov/energysaver/weatherize/insulation
3. How does the atmosphere act as an insulator?
The atmosphere soaks in the sun’s heat and keeps it inside its layers, warming
the Earth throughout day and night. This process is known as the Greenhouse Effect. It
won’t let heat from the Earth escape into outer space, nor will it allow heat from outer
space to penetrate into Earth.
https://www.ducksters.com/science/atmosphere.php
7. Lab Experiment: April 28-30
*Conduct an experiment to determine the Specific Heat of 3 different metals.
A. LAB TEMPLATE
B. LAB RUBRIC - Focus on DATA ANALYSIS SECTION
C. Research a Phenomenon in nature that relates to Specific Heat
8. SPECIFIC HEAT WORKSHEET
WORKSHEET LINK - Use this worksheet and show your work
Use this website for examples
http://www.kentchemistry.com/links/Energy/SpecificHeat.htm
9. TEST REVIEW
Specific Heat Problems
Video Lessons:
1. https://www.youtube.com/watch?v=4RkDJDDnIss
2. https://www.youtube.com/watch?v=2uHQLZ3gJAc
3. https://www.youtube.com/watch?v=tU-7gQ1vtWo
DIRECTIONS: Heat = mass * change in temperature * Specific Heat
1. A 15.75-g piece of iron absorbs 1086.75 joules of heat energy, and its temperature changes from
25°C to 175°C. Calculate the specific heat capacity of iron.
Heat = mass * change in temperature * Specific Heat
1086.75 J = 15.75 g * 150°C * specific heat
1086.75 J = 2362.5 g°C * specific heat
Specific Heat of Iron = 0.46 J/g°C
2. How many joules of heat are needed to raise the temperature of 10.0 g of aluminum from 22°C to
55°C, if the specific heat of aluminum is 0.90 J/g°C?
Heat = mass * change in temperature * Specific Heat
Heat = 10 g * 33 C * 0.9 J/g°C
Heat = 297 J
3. To what temperature will a 50.0 g piece of glass raise if it absorbs 5275 joules of heat and its
specific heat capacity is 0.50 J/g°C? The initial temperature of the glass is 20.0°C.
Heat = mass * change in temperature * Specific Heat
5275 = 50 g * (final temperature - 20°C) * 0.5 J/g°C
5275 = 25 J°C * (final temperature - 20 °C)
(final temperature - 20°C) = 211°C
Final temperature = 231°C
4. Calculate the heat capacity of a piece of wood if 1500.0 g of the wood absorbs 6.75×104 joules of
heat, and its temperature changes from 32°C to 57°C.
Heat = mass * change in temperature * Specific Heat
67,500 J = 1500 g * (57°C - 32°C) * specific heat
67,500 J = 1500 g * 25°C * specific heat
67,500 J = 37,500 g°C * specific heat
Specific Heat = 1.8 J/g°C
5. 100.0 mL of 4.0°C water is heated until its temperature is 37°C. If the specific heat of water is
4.18 J/g°C, calculate the amount of heat energy needed to cause this rise in temperature.
Heat = mass * change in temperature * Specific Heat
Heat = 100 g * (37°C - 4°C) * 4.18 J/g°C
Heat = 100 g * 33°C * 4.18 J/g°C
Heat = 13,794 J
6. 25.0 g of mercury is heated from 25°C to 155°C, and absorbs 455 joules of heat in the process.
Calculate the specific heat capacity of mercury.
Heat = mass * change in temperature * Specific Heat
455 J = 25 g * (155°C - 25°C) * specific heat
455 J = 25 g * 130°C * specific heat
455 J = 3250 g°C * specific heat
Specific heat = 0.14 J/g°C
7. What is the specific heat capacity of silver metal if 55.00 g of the metal absorbs 47.3 c alories of
heat and the temperature rises 15.0°C?
Heat = mass * change in temperature * Specific Heat
47.3 cal = 55 g * 15°C * specific heat
47.3 cal = 825 g°C * specific heat
Specific heat = 0.057 cal/g°C
8. If a sample of chloroform is initially at 25°C, what is its final temperature if 150.0 g of
chloroform absorbs 1000 joules of heat, and the specific heat of chloroform is 0.96 J/g°C?
Heat = mass * change in temperature * Specific Heat
1000 J = 150 g * (final temperature - 25°C) * 0.96 J/g°C
1000 J = 144 J°C * (final temperature - 25°C)
(final temperature - 25°C) = 6.94°C
Final temperature = 31.94°C
9. How much energy must be absorbed by 20.0 g of water to increase its temperature from 283.0 °C
to 303.0 °C? (Cp of H2 O = 4.184 J/g °C)
Heat = mass * change in temperature * Specific Heat
Heat = 20 g * (303° C - 283°C) * 4.184 J/g°C
Heat = 1673.6 J
10. When 15.0 g of steam drops in temperature from 275.0 °C to 250.0 °C, how much heat energy is
released?
(Cp of H2 O = 4.184 J/g °C)
Heat = mass * change in temperature * Specific Heat
Heat = 15 g * (275°C - 250°C) * 4.184 J/g°C
Heat = 1569 J
11. How much energy is required to heat 120.0 g of water from 2.0 °C to 24.0 °C? (Cp of H2O = 4.184
J/g °C)
Heat = mass * change in temperature * Specific Heat
Heat = 120 g * (24° C - 2°C) * 4.184 J/g°C
Heat = 11,045.76 J
12. How much heat (in J) is given out when 85.0 g of lead cools from 200.0 °C to 10.0 °C? (Cp of Pb
= 0.129 J/g °C)
Heat = mass * change in temperature * Specific Heat
Heat = 85 g * (200°C - 10°C) * 0.129 J/g°C
Heat = 2083.35 J
13. If it takes 41.72 joules to heat a piece of gold weighing 18.69 g from 10.0 °C to 27.0 °C, what is
the specific heat of the gold?
Heat = mass * change in temperature * Specific Heat
41.72 J = 18.69 g * (27°C - 10°C) * specific heat
41.72 J = 317.73 g°C * specific heat
Specific Heat = 0.131 J/g°C
14. A certain mass of water was heated with 41,840 Joules, raising its temperature from 22.0 °C to
28.5 °C. Find the mass of the water, in grams. (Cp of H2 O = 4.184 J/g °C)
Heat = mass * change in temperature * Specific Heat
41,840 J = mass * (28.5°C - 22°C) * 4.184 J/g°C
41,840 J = mass * 27.196 J/g
Mass = 1538.46 g
15. How many joules of heat are needed to change 50.0 grams of ice at -15.0 °C to steam at 120.0
°C?
(Cp of H2 O = 4.184 J/g °C)
Heat = mass * change in temperature * Specific Heat
Heat = 50 g * (120° C + 15°C) * 4.184 J/g°C
Heat = 28,242 J
16. Calculate the number of joules given off when 32.0 grams of steam cools from 110.0 °C to ice at
-40.0 °C.
(Cp of H2 O = 4.184 J/g °C)
Heat = mass * change in temperature * Specific Heat
Heat = 32 g * (110°C + 40°C) * 4.184 J/g°C
Heat = 20,083.2 J
17. The specific heat of ethanol is 2.46 J/g o C. Find the heat required to raise the temperature of 193 g
of ethanol from 19o C to 35oC.
Heat = mass * change in temperature * Specific Heat
Heat = 193 g * (35° C - 19°C) * 2.46 J/g°C
Heat = 7596.48 J
18. When a 120 g sample of aluminum (Al) absorbs 9612 J of energy, its temperature increases from
25oC to 115o C . Find the specific heat of aluminum.
Heat = mass * change in temperature * Specific Heat
9612 J = 120 g * (115°C - 25°C) * specific heat
9612 J = 10,800 g°C * specific heat
specific heat = 0.89 J/g°C
Specific Heat Practice Problem
Mass Mass Δ Temp Δ Temp Heat Heat Lost Real Specific
Object Metal Water H20 Metal Gain
H20 Metal SH Metal Heat
Example 65 100 75-27 = 48 Use
28.4 600 600 notes
Copper - 19.6
S4 28.6 100 24.3-22.5 86-24.3 180 180 0.103
19.5
Aluminu 28.4 100 25.5-22 97.8-25.5
m - S4 19.6
100 24.8-23.1= 76.8-24.8= 170 170 0.11
Copper - 1.7 52
S7
100 25.5-22= 77.9-25.5=
Aluminiu
m - S7 100 25-22.5=2. 78.1-25=
5
Copper
S2 100 26-24=2 78-26= 200 200 0.196 0.215
Aluminiu
m-S2
1. What is the difference between heat and temperature?
a. Heat is the amount of energy from the movement of atoms inside a substance,
while temperature is a measurement of the speed of the atoms inside the
substance, or a measurement of heat energy.
2. How is water different from the metals?
a. Water is different from the metals because it is not a conductor of heat, and as a
result, has a high specific heat. That gives it special properties which are unique
from metals.
3. How does specific heat relate to the real world? Provide examples.
a. Specific heat relates to the real world in the natural, chemical, and mechanical
world such as smelting, the water boiling in a pot, and drilling.
Specific Heat Lab
Name: Amy Zhang
Class: 3
Teacher: Lopez
Date: 5/16
Investigation Title: Specific Heat Lab
I. Investigation Design
A. Problem Statement:
Find the specific heat of a metal compared to water
B. Hypothesis: (Hint: Something about comparing metals to water - use increase or decrease)
If the specific heat of a metal is found, then it would be less than the specific heat of the
water, because metals are better conductors of heat than water.
C. Independent Variable: x
Aluminum Zinc
D. Dependent Variable: y
Specific Heat
E. Constants: Volume of beaker Starting temperature of water
Amount of water (mL)
F. Control:
*What substance makes good control in many labs?
Good ‘ol Water
G. Materials: (List with numbers)
1. Triple Balance Beam
2. Calorimeter
3. Glass Beakers
4. Metal Object
5. Thermometer
6. Tongs
H. Procedures: (List with numbers and details)
1. Gather materials
2. Measure mass of metal on triple beam balance to nearest tenth of gram and record.
3. Fill Calorimeter Cup (Foam coffee cup) with exactly 100 grams of water.
4. Record temperature of water in calorimeter cup to nearest tenth of degree Celsius
5. Fill glass beaker halfway with hot water and submerge metal in beaker.
6. Leave metal in hot water until the temperature stops rising.
7. Record the hot water temperature after temperature stops rising. - M etal Initial Temp.
8. Use tongs to remove metal from hot water and carefully place into calorimeter cup and
close lid with thermometer placed in spout.
9. Record Final Temperature for Metal and Water after the water temperature stops rising.
10. Perform the calculations using the examples discussed class - Record Specific Heat for
the metal.
A. Heat Gained Water = mass of water * Change in temp of water * Specific Heat of Water
B. Heat Lost Metal = Mass of metal * Change in Temp of Metal * Specific Heat of Metal
II. Data Collection
A. Qualitative Observations: (Describe the metals using characteristics)
Aluminum: Shiny luster, light-silver color, soft and smooth texture
Zinc: S hiny luster, bluish-silver, brittle and smooth texture
B. Quantitative Observations: (Key data)
1. Data Table
27.1 - 24.7 = 77.8 - 27.1 =
Aluminum 19.9 100 2.4 50.7 240 240 0.238
Zinc 150 150 0.095
23.6 - 22.1 = 75.8 - 23.6 =
30.1 100 1.5 52.2
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