Velocity: t he speed of Final Velocity: i s the Key Metric Units: A
something in a given velocity at the final point system of measurement
direction. of time. in which the basic units
are the meter, the second,
and the kilogram.
What is the difference between speed and velocity?
Speed is the time rate at which an object is moving, while velocity is the rate and
direction of an object's movement. Put in another way, speed is a scalar value, while
velocity is a vector.
We chose Aberdeen, Scotland to London, England.
⇨
How
Long Would it Take A...
Fastest Runner - Usain Bolt
T = D/V
T = 878058.09 m / 8442.86 m per sec
T = 104 hours
Model T Ford
T = D/V
T = 545.6 mi / 45 mph
T = 12 hours
Hindenburg
T = D/V
T = 545.6 mi / 84 mph
T = 6.5h
Tesla at Top Speed
T = D/V
T = 878.1 km / 250 kmph
T = 3.5 hours
Fastest Train
T = D/V
T = 545.6 m/ 375 mph
T = 1.45 hours
F 35 Fighter Jet
T = D/V
T = 545.6 m / 1200 mph
T = .45; 27 minutes
Lamborghini
T = D/V
T = 545.6 / 217
T = 2.5 hours
Graph:
18% increase in Velocity for each vehicle - Show how the Times would
be affected by the increase in speed. Show a double bar graph with the 2 different
times for each vehicle.
*Include pictures and brief description of each mode of transportation
Fastest Runner - Usain Bolt
T = D/V
T = 878058.09 m / 9962.5 m per sec
T = 88 hours
Model T Ford
T = D/V
T = 545.6 mi / 53.1 mph
T = 10.3 hours
Hindenburg
T = D/V
T = 545.6 mi / 99.12
mph
T = 5.5 hours
Tesla at Top Speed
T = D/V
T = 878.1 km / 295 km/h
T = 2.9 hours
Fastest Train
T = D/V
T = 545.6 m/ 442.5 mph
T = 1.23 hours
F 35 Fighter Jet
T = D/V
T = 545.6 mi / 1416 mph
T = .38; 23 minutes
Lamborghini
T = D/V
T = 545.6 mi / 256.06 mph
T = .47; 28.5 minutes
When we arrive, we would like to see Buckingham
Palace, the London Eye, and the Tower of London. A
restaurant we would like to visit is Nando’s.
London, the capital city of England and the United
Kingdom, has a history going back over 2,000 years. During
that time it has grown to one of the world's most significant
financial and cultural capital cities. It has withstood plague,
devastating fire, civil war, aerial bombardment, terrorist
attacks, and rioting.
How long it would take the F 35 Fighter Jet to get to...
The Sun
T = D/V
T = 9.296 × 107 mi / 1200 mph
T = 8.8 years
Saturn
T = D/V
T = 7.46 × 108 mi / 1200 mph
T = 70 years
Neptune
T = D/V
T = 2.7 × 109 mi / 1200 mph
T = 256 years
Unit 1: Uniform Motion Name: G race Cox
Worksheet 8 Date: 2/22/18 Period: S3
Speed and Velocity Problems
1. What is the average speed of a cheetah that sprints 100 m in 4 s? How about if it sprints
50 m in 2 s?
Velocity = Distance/Time
Velocity = 100m/4secs
Velocity = 25m/seconds
2. If a car moves with an average speed of 60 km/hr for an hour, it will travel a distance of
60 km. How far will it travel if it continues this average rate for 4 hrs?
Distance = velocity • Time
Distance = 60 km/hr • 4 hrs.
Distance = 15 km
3. A runner makes one lap around a 200 m track in a time of 25.0 s. What was the runner's
average speed? Answer: 8.0 m/s
Velocity = Distance/Time
Velocity = 200m/25s
Velocity = 8 m/s
4. Light and radio waves travel through a vacuum in a straight line at a speed of very nearly
3.00 × 108 m/s. How far is light year (the distance light travels in a year)? Answer: 9.50
× 101 5 m.
Distance = velocity • Time
Distance = (3.00 • 108 m/s)(3.15 • 107 )
Distance = 9.50 × 101 5 m.
5. A motorist travels 406 km during a 7.0 hr period. What was the average speed in km/hr
and m/s? Answers: 58 km/hr, 16 m/s.
Velocity = Distance/Time
Velocity = 406km/7 hours
Velocity = 58km/h
Velocity = 16m/s
6. A bullet is shot from a rifle with a speed of 720 m/s. What time is required for the bullet
to strike a target 3240 m away? Answer: 4.5 s.
Time = Distance/Velocity
Time = 3240m/720m/s
Time = 4.5s
7. Light from the sun reaches the earth in 8.3 minutes. The speed of light is 3.0 × 108 m/s.
In kilometers, how far is the earth from the sun? Answer: 1.5 × 108 km.
Distance = Velocity • Time
Distance = 3 • 108 m/s • 498s
Distance = 1.494 • 101 1m /103
Distance = 1.494 • 108 km
8. •An auto travels at a rate of 25 km/hr for 4 minutes, then at 50 km/hr for 8 minutes, and
finally at 20 km/hr for 2 minutes. Find the total distance covered in km and the average
speed for the complete trip in m/s. Answers: 9 km, 10.7 m/s.
Distance = 25km/hr • 1hr/60min • 4min+50 km/hr • 1hr/60min • 8min+20km/hr • 1hr/60min •
2min
Distance = 1.7km+6.7km+0.7km
Distance = 9km
Velocity = 9000m/14min • 60sec
Velocity = 10.7 m/s
9. •If you traveled one mile at a speed of 100 miles per hour and another mile at a speed of
1 mile per hour, your average speed would not be (100 mph + 1 mph)/2 or 50.5 mph.
What would be your average speed? (Hint: What is the total distance and total time?)
Answer: 1.98 mph.
Time = 0.01hr+1hr=1.01hr
Velocity = Distance/Time
Velocity = 2miles/1.01hr
Velocity = 1.98mph
10. •What is your average speed in each of these cases?
a. You run 100 m at a speed of 5.0 m/s and then you walk 100 m at a speed of 1.0
m/s.
b. You run for 100 s at a speed of 5.0 m/s and then you walk for 100 s at a speed of
1.0 m/s. Answers: 1.7 m/s, 3.0 m/s.
Time = 100m/5ms+100/1ms =120s
Velocity = Distance/Time
Velocity = 200m/120s
Velocity = 1.7m/s
Distance = Velocity
Distance = 100s • 5m/s+100s • 1m/s
Distance = 500m+100m
Distance = 600m
Velocity = 600m/200s
Velocity = 3m/s
11. •A race car driver must average 200 km/hr for four laps to qualify for a race. Because of
engine trouble, the car averages only 170 km/hr over the first two laps. What average
speed must be maintained for the last two laps?
(800-340)/2=230mph
12. •A car traveling 90 km/hr is 100 m behind a truck traveling 50 km/hr. How long will it
take the car to reach the truck?
40000m/hr • 1hr/60min • 1min/60s=11m/s
T=100m/11m/s=9.09s
13. The peregrine falcon is the world's fastest known bird and has been clocked diving
downward toward its prey at constant vertical velocity of 97.2 m/s. If the falcon dives
straight down from a height of 100. m, how much time does this give a rabbit below to
consider his next move as the falcon begins his descent?
T=100m/97.2m/s=1.02s
T=1.02s
T=D/V
More Speed and Velocity Problems
14. Hans stands at the rim of the Grand Canyon and yodels down to the bottom. He hears his
yodel back from the canyon floor 5.20 s later. Assume that the speed of sound in air is
340.0 m/s. How deep is the canyon?
D=(340m/s•5,2s)/2=884m
15. The horse racing record for a 1.50 mi. track is shared by two horses: Fiddle Isle, who ran
the race in 143 s on March 21, 1970, and John Henry, who ran the same distance in an
equal time on March 16, 1980. What were the horses' average speeds in:
a. mi/s?
b. mi/hr?
a. V=1.5mile/143s=0.01mile/s
b. V=1.5mile/143s•60s/min•60min/hr=37.76mile/hr
16. For a long time it was the dream of many runners to break the "4-minute mile." Now
quite a few runners have achieved what once seemed an impossible goal. On July 2,
1988, Steve Cram of Great Britain ran a mile in 3.81 min. During this amazing run, what
was Steve Cram's average speed in:
a. mi/min?
b. mi/hr?
Velocity = Distance/Time
a. V=1mile/3.81min=0.26mile/min
b. V=1mile/3.81min•60min/hr=15.7mile/hr
17. It is now 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 first hallway, a distance of
35.0 m, at a speed of 3.50 m/s. The second hallway is filled with students, and she covers
its 48.0 m length at an average speed of 1.20 m/s. The final hallway is empty, and
Suzette sprints its 60.0 m length at a speed of 5.00 m/s.
a. Does Suzette make it to class on time or does she get detention for being late
again?
b. Draw a distance vs. time graph of the situation. (Assume constant speeds for each
hallway.)
a. T=(35m/3.5m/s)+(48m/1.2m/s)+(60m/5m/s)=62s. Suzerre is late again.
18. During an Apollo moon landing, reflecting panels were placed on the moon. This
allowed earth-based astronomers to shoot laser beams at the moon's surface to determine
its distance. The reflected laser beam was observed 2.52 s after the laser pulse was sent.
The speed of light is 3.0 × 108 m/s. What was the distance between the astronomers and
the moon?
Distance = velocity • Time
D=2.52s•3.0 x 108 =7.56x108 m
19. For many years, the posted highway speed limit was 88.5 km/hr (55 mi/hr) but in recent
years some rural stretches of highway have increased their speed limit to 104.6 km/hr (65
mi/hr). In Maine, the distance from Portland to Bangor is 215 km. How much time can
be saved in making this trip at the new speed limit?
Travel at 88.5km/hr, T=215km/88.5km/hr=2.43hr
Travel at 104.6km/hr, T=215km/104.6km/hr=2.06hr
Time saved=2.43hr-2.06hr=0.37hr
20. 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 0.2000 m/s while the rabbit runs
the first 200.0 m at 2.000 m/s The rabbit then stops to take a nap for 1.300 hr and
awakens to finish the last 800.0 m with an average speed of 3.000 m/s. Who wins the
race and by how much time?
Time for rabbit to travel
1000m=(200m/2m/s)+1.3hr+(800m/3m/s)=100s+(1.3•3600)s+266.7s=5046.7s
Time for tortoise to travel 1000m=1000m/0.2m/s=5000s
The tortoise win the race.
21. Two physics professors challenge each other to a 100. m race across the football field.
The loser will grade the winner's physics labs for one month. Dr. Rice runs the race in
10.40 s. Dr. De La Paz runs the first 25.0 m with an average speed of 10.0 m/s, the next
50.0 m with an average speed of 9.50 m/s, and the last 25.0 m with an average speed of
11.1 m/s. Who gets stuck grading physics labs for the next month?
100m=25m/10m/s+50m/9.5m/s+25m/11.1m/s=2.5s+5.3s+2.3s=10.1s Time for Dr Rice to run
100m=10.4s Dr Rice lost and will be grading physics lab for the next month.
Acceleration Data
Independent Variable: Angle of Ramp
Dependant Variable: Acceleration
Velocit Velocit
Trial Dist. 1 Time 1 y 1 Dist. 2 Time 2 y 2 Acceleration
3.3 m/s2
angle 1 = 24.7 1.2 2.35 2.5 m/s2
13.3 m/s2
deg 61cm 0.51s m/s 61cm 0.26s m/s 5.3 m/s2
angle 1 = 1.7 2.35
24.7deg 61cm 0.36s m/s 61cm 0.26s m/s
angle 1 = 24.7 1.7
deg 61cm 0.36s m/s 61cm 0.16s 3.8 m/s
1.5
avg. 61cm 0.41s m/s 61cm 0.23s 2.7 m/s
angle 2 = 13.3 61cm 0.74 61cm 0.34s 1.8 m/s 3.1 m/s2
deg 61cm 0.82s m/s 61cm 0.46s 1.3 m/s .78 m/s2
angle 2 = 13.3 61cm 61cm 0.44s 1.4 m/s 1.2 m/s2
deg 61cm 0.97 61cm 0.41s 1.5 m/s 1.5 m/s2
angle 2 = 13.3 0.63s m/s
deg
0.83
avg. 0.73s m/s
0.84
0.726s m/s
Acceleration Conclusion
Problem Statement: How does the angle of the ramp affect the acceleration of the car?
Key words: Purpose of experiment, Hypothesis, variables, data to prove your hypothesis
The purpose of this experiment was to figure out how the angle of the ramp affects the
acceleration of the car. Our hypothesis was if the angle of the ramp is decreased, then the
acceleration of the car will increase. In this experiment, the independent variable was the angle
of the ramp because that was the thing we changed. The dependent variable was the
acceleration (m/s2) because that was the thing we measured. Our hypothesis was incorrect
because the acceleration in fact decreased as the angle of the ramp decreased in degrees.
When the angle of the ramp was 24.7 degrees, the average acceleration was 5.3 m/s2. And
when the angle was reduced to 13.3 degrees, the average acceleration became 1.5 m/s2.
Obviously, 13.3 deg is less than 24.7 deg, and 1.5 m/s2 is less than 5.3 m/s2. Ergo, our
hypothesis was erroneous. Ultimately, after conducting this experiment, we hold new
knowledge on how the angle of a ramp affects the acceleration of a car - When the angle
declines, the acceleration follows suit.
Acceleration Worksheet.
14.2 Acceleration
Acceleration is the rate of change in the speed of an object. To determine the rate of acceleration,
you use the formula below. The units for acceleration are meters per second per second or m/s2.
A positive value for acceleration shows speeding up, and negative value for acceleration shows
slowing down. Slowing down is also called d eceleration.
The acceleration formula can be rearranged to solve for other variables such as final speed (v2 )
and time (t ) .
EXAMPLES
1. A skater increases her velocity from 2.0 m/s to 10.0 m/s in 3.0 seconds. What is the skater’s
acceleration?
Looking for Solution
Acceleration of the skater
The acceleration of the skater is 2.7 meters per
second per second.
Given
Beginning speed = 2.0 m/s
Final speed = 10.0 m/s
Change in time = 3 seconds
Relationship
2. A car accelerates at a rate of 3.0 m/s2. If its original speed is 8.0 m/s, how many seconds will it
take the car to reach a final speed of 25.0 m/s?
Looking for Solution
The time to reach the final speed.
`
The time for the car to reach its final speed is 5.7
seconds.
Given
Beginning speed = 8.0 m/s; Final speed = 25.0 m/s
Acceleration = 3.0 m/s2
Relationship
1. W hile traveling along a highway a driver slows from 24 m/s to 15 m/s in 12 seconds. What is
the automobile’s acceleration? (Remember that a negative value indicates a slowing down
or deceleration.)
A = (V2 - V1)/T2
A = (15 m/s - 24 m/s)/12 Sec
A = -9 m/s/12 sec.
A = -.75 m/s2
2. A parachute on a racing dragster opens and changes the speed of the car from 85 m/s to 45
m/s in a period of 4.5 seconds. What is the acceleration of the dragster?
A = (V2 - V1)/T2
A = 45 m/s - 85 m/s / 4.5 sec
A = -40 m/s / 4.5 sec
A = -8.9
4. A car traveling at a speed of 30.0 m/s encounters an emergency and comes to a complete
stop. How much time will it take for the car to stop if it decelerates at -4.0 m/s2?
T = (V2 - V1)/A
T = (0 m/s - 30 m/s)/-4 m/s2
T = -30m/s / -4 m/s2
T = 7.5 sec
5. If a car can go from 0 to 60 mi/hr in 8.0 seconds, what would be its final speed after 5.0
seconds if its starting speed were 50 mi/hr?
A = (V2 - V1)/T2
A = 60 mph - 0 mph / 8 sec
A = 60 mph / 8 sec
A = 7.5 m/s2
-------------------------------------
V2 = V1 + (at)
V2 = 50 mph + (7.5 m/s2 * 5 sec)
V2 = 87.5 mph
6. A cart rolling down an incline for 5.0 seconds has an acceleration of 4.0 m/s2. If the cart
has a beginning speed of 2.0 m/s, what is its final speed?
V2 = V1 + (at)
V2 = 2 m/s + (4m/s2*5sec)
V2 = 22 m/s
7. A helicopter’s speed increases from 25 m/s to 60 m/s in 5 seconds. What is the acceleration
of this helicopter?
A = (V2 - V1)/T2
A = 60 m/s - 25 m/s / 5 sec
A = 35 m/s / 5 sec
A = 7 m/s2
8. As she climbs a hill, a cyclist slows down from 25 mi/hr to 6 mi/hr in 10 seconds. What is
her deceleration?
A = (V2 - V1)/T2
A = 25 mi/hr - 6 mi/hr / 10 sec
A = 21 mi/hr / 10 sec
A = 2.1 m/s2
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 + (7m/s2*6sec)
V2 = 67 m/s
10. A car starting from rest accelerates at a rate of 8.0 m/s/s. What is its final speed at the end
of 4.0 seconds?
A = (V2 - V1)/T2
A = 8 m/s - 0 m/s / 4 sec
A = 8 m/s / 4 sec
A = 2 m/s2
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)/T2
A = 10 m/s - 0 / 6 sec
A = 10 m/s / 6 sec
A = 1.7 m/s2
12. A cyclist accelerates at a rate of 7.0 m/s2. How long will it take the cyclist to reach a speed
of 18 m/s?
T = (V2 - V1)/A
T = 18 m/s-7 m/s / 7 m/s2
T = 11 m/s / 7 m/s2
T = 1.6 sec
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 acceleration?
A = (V2-V1)/T2
A = 0 m/s - 7 m/s / 3 sec
A = -7 m/s / 3 sec
A = -2.3 m/s2
GPE Project Presentation
QUIZ REVIEW #1:
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?
Explain your energy transformations on the ride.
GPE = KE
Mgh = .5mv2
230 kg * 12.05 m/s * 125 m = .5 * 230 kg * v2
346437.5 j = 115v2
√3012.5 = √v²
55 m/s = v
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?
Gpe = mgh
2130 j = 89 kg * 9.8 m/s * h
2130 j = 872.2h
2.4 m = h
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?
GPE = mgh
1250 j = m * 9.8 m/s * 629 m
1250 j = 6164.2m
4. With an elevation of 5334 m above sea level, the village of Aucanquilcha, Chile is the highest
inhabited town in the world. What would be the gravitational potential energy associated with a
95 kg person in Aucanquilcha?
GPE = mgh
GPE = 95 kg * 9.8 m/s * 5334 m
GPE = 4,965,954 j
QUIZ REVIEW 2: 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. Hoth 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 mass 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:
Earth Hoth
GPE = KE GPE = KE
m*g*h = .5mv2 m*g*h = .5mv2
7000 kg * 9.8 m/s * 125 m = .5 * 7000 kg * v2 7000 * 13.4 m/s * 125 m = .5kg * 7000 kg *
8575000j = 3500v2 v2
√2450 j = √v² 11725000 = 3500v2
49.5 m/s = v √3350 = √v2
57.9 m/s = v
Data Table:
Planet Gravity (m/s) Velocity (m/s)
Earth 9.8 49.5
Hoth 13.4 57.9
Graph:
Conclusion:
Hoth’s gravity would be better planet for the rollercoaster. This is because it
would be going a lot faster with a speed of 11725000m/s2 , while earth is only going
8575000m/s2. The graph shows how the greater the KE the greater the GPE will be. Hoth
has a larger GPE of 11725000m/s2 and also has the larger KE of 628460J. Earth had the
lower GPE of 8575000m/s2 and a lower KE of 336140J. This shows how the difference in
Gravity can change the speed of two of the same rollercoasters. You would use more
restraints on the rollercoaster on Hoth due to the fast speed.
Inclined Plane Practice Problems
1. Scenario: S uppose you would like to bring a 125 N box up to a height of 1 7 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 5 3 m. You also measure the Force (N) needed to push the box up the
ramp which is 89 N. What is the Work Output, Work Input, Ideal Mechanical Advantage, Actual
Mechanical Advantage, and Efficiency of the machine?
Work Output
W (out) = F (out) * D (out)
125 N * 17 M = 2125 J
Work Input
W (in) = F (in) * D (in)
53 m * 89 N = 4717 J
IMA
D (in) / D (out)
53 N / 17 M = 3.1 J
AMA
F (out) / F (in)
89 N / 125 N = .71 J
Efficiency
W (out) / w (in) * 100
2125 J / 4717 J * 100 = 45%
2. 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?
A. Use “Drawing” to label a triangle (Inclined Plane)
a.
B. Calculate the angle of the ramp.
a. Hypotenuse * Height
48m * 29m
1392 Degrees
C. Calculate the Ideal Mechanical Advantage (IMA)
a. 48m/29m
1.7 = IMA
D. Calculate the Actual Mechanical Advantage (AMA)
a. 85m/175m
2.05 = AMA
E. Calculate the Efficiency (%)
a. Work output/work input X 100
205%
Questions:
1. Is this machine possible? Explain using evidence from the problem.
a. This machine is not possible because it has a doesn't have a reasonable
IMA(1.7) ,AMA(2.05) , and Efficiency(205%).
2. How could you change the Input Force or Distance or to make it possible?
a. You can change it to 85 to make it come out to 1.3 degrees for the IMA. This
would make the machine possible.
3. How would this problem be different on another planet?
a. The gravity pull would make a difference in the weight of the Neutrons
because it would change the weight.
QUIZ: Inclined Plane
QUIZ: Wednesday and Thursday
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 you increase the angle of the ramp, then the weight of neutrons will increase
Diagrams of Inclined Planes: (Use DRAWING - Label Diagrams)
Angle Chart: h ttps://drive.google.com/open?id=0B4RmhXJlHvo1YXZhcDNMSDNSMXc
Calculations ( Examples):
IMA- 4 .3 AMA- 3 Efficiency- 70
IMA- 1.4 AMA- 1.5 Efficiency- 105
Data Table: ( Located on Google Classroom)
Trial Output Output Output Input Input Input IMA AMA Efficiency
Force (N) Dist. (m) Work (J) Force Dist. Work
Angle = 12 70 840 4 300 1200 4.3 3 70%
13
Angle = 12 70 840 6 200 1200 2.9 2 70%
21
Angle = 12 70 840 8 100 800 1.4 1.5 105%
45
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 )1
5. Use this source to explain the relationship of this machine to
Newton’s First Law of Motion.
My hypothesis was if you increase the angle of the ramp, than the
weight of the newtons will increase. The angle of 45 degrees in
impossible in this problem. This is because the efficiency is 105% and to
be a possible angle, the efficiency has to be under 100%. A possible
machine is shown in angle 13. The efficiency is under 100% at 70%. This
shows the impossible machine and the possible one. The law of
conservation of energy shows this about having to be 100% to be a
possible machine (Encyclopedia Britannica). This machine connects with
the Newton's first law of motion because the incline plane stays at rest,
which is said in the law “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.”
1 "Introduction to mechanical advantage (video) | Khan Academy."
https://www.khanacademy.org/science/physics/work-and-energy/mechanical-advantage/v/introduction-to-
mechanical-advantage. Accessed 9 Apr. 2018.
Thermal (Heat) Energy Project
Chapter 6 (pg. 156-180)
DUE: Friday May 16th
1. Vocabulary - Define and make note cards or quizlet
Conduction - Heat - Insulator - Calorie -
The transfer of heat The quality of A material of such Either of two units
between two parts of being hot; high low conductivity of heat energy.
a stationary system, temperature. that the flow of
caused by a current through it is
temperature insignificant.
difference between
the parts.
Convection - Temperature - Second Law of Turbine -
The transfer of heat A measure of the Thermodynamics - Any of various
by the circulation or warmth or The principle that machines having a
movement of the coldness of an no cyclic process is rotor, usually with
heated parts of a object or possible in which vanes or blades,
liquid or gas. substance with heat is absorbed driven by the
reference to some from a reservoir at pressure,
standard value. a single momentum, or
temperature and reactive thrust of a
converted moving fluid, as
completely into steam, water, hot
mechanical work. gases, or air.
Radiation - Heat Engine - Specific Heat - Generator -
The process in which A mechanical A mechanical An apparatus for
energy is emitted as device designed device designed to producing a gas or
particles or waves. to transform part transform part of vapor.
of the heat the heat entering it
entering it into into work.
work.
First Law of Conductor - Kinetic Energy -
Thermodynamics - A substance, The energy of a
Any of three principles body, or device body or a system
variously stated in that readily with respect to the
equivalent forms, conducts heat, motion of the body
being the principle electricity, sound, or of the particles in
that the change of etc. the system.
energy of a
thermodynamic
system is equal to the
heat transferred
minus the work done.
2. Provide a diagram showing molecular motion in Solids, Liquids, and gases.
*How are they different?
The molecules in the molecular motion of a solid are very compacted and
cramped together. The liquid molecules are more spaced out but not by much so that
the molecules are able to move around and create a liquid. Gas molecules are very
spread out and not touching. This lets the molecules roam freely.
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 = Mass * Heat of Fusion
H = M * Hfusion
H = 15 g * 334 J/G
H = 5010
Heat = Mass * Change in Temperature * SH
H = M * ΔT * SH
H = 15 g * 0 * 4 Cal
H=0
Heat = Mass * Heat of Vaporization
H = M * Hvaporization
H = 15 g * 40.65 J/G
H = 609.75
4. What is the difference between Heat and Temperature? Provide a definition,
picture and video link to help you review.
Heat: The quality of being hot and/or being at a high temperature.
Temperature: The measure of the warmth or coldness of an object or substance
with reference to some standard value.
What is The Difference? (Link)
5. Construct a graph showing the average monthly
temperatures in ( Hartford, CT). , a city on the equator
(Indonesia) a nd a city in the Southern Hemisphere
(Melbourne).
Questions:
1. What do you notice about the temperatures?
Indonesia has the highest average monthly temperatures with a total average of
87.5℉. Melbourne had the lowest monthly temperature average with 60.3℉. Hartford, CT,
had a average of 60.9℉ which is very close to Melbourne's average temperature.
2. How is heat transferred throughout the Earth?
Heat is transferred through the earth's surface and the atmosphere’s convection
and radiation.
4. How is Steam used to create electricity in Power Plants?
A. Coal Plant: First the thermal coal is pulverised to a fine powder and then it is burned
which turns the liquid to steam. The stream is then put at a very high pressure. By doing
this the steam is able to spin a turbine that is connected to an electric generator. The
spinning turbine is used to turn large magnets to turn within copper wire coils, and this
is the generator. The moving magnets cause the electrons in the wires to move from
one place to another, creating a electrical current and producing electricity.
B. Natural Gas Plant
The most basic natural gas-fired electric generation consists of a steam generation unit,
where fossil fuels are burned in a boiler to heat water and produce steam that then turns
a turbine to generate electricity.
C. Nuclear Plant
Nuclear energy originates from the splitting of uranium atoms – a process called fission.
This generates heat to produce steam, which is used by a turbine generator to generate
electricity.
D. Where did Fossil Fuels originate?
All three types of Fossil Fuels were formed many hundreds of millions of years ago
before the time of the dinosaurs – hence the name fossil fuels.
E. What is the difference between Renewable and NonRenewable forms of
energy?
Non-renewable energy resources, like coal, nuclear, oil, and natural gas, are available
in limited amounts. This is usually due to the long time it takes for them to be
replenished. Renewable resources are replenished naturally and over relatively short
periods of time.
5. Critical Thinking Questions
1. What happens to the molecules in each of the beakers as heat is added?
When heat is added to a substance, the molecules and atoms vibrate faster. As atoms
vibrate faster, the space between atoms increases. The motion and spacing of the
particles determines the state of matter of the substance. The end result of increased
molecular motion is that the object expands and takes up more space.
2. Why is water a great substance to put into a car engine radiator?
Because water has such a high heat capacity - particularly its volumetric heat capacity.
It takes a tremendous amount of energy to change the temperature of water, giving it
enormous cooling capacity compared to most metals (rapidly absorbing heat energy
from the engine).
6. Practice Calculation
1. How much heat was gained by a 50 g sample of Vinegar that increased its
temperature from 35 C to 75 C?
Heat = Mass * Heat of Fusion
Heat = Mass * Change in Temperature * SH
Heat = Mass * Heat of Vaporization
Heat = 50 g * 45.9 cal/g
Heat = 2295 cal
Heat = 50 g * 40 C * 2.043
Heat = 4086
Heat = 50 * 11
Heat = 550
Total Heat = 6931 cal
7. Critical Thinking Questions
1. How did NASA protect the astronauts in their space vehicles from the harmful
radiation from space?
Materials that could be used to protect astronauts and spacecraft from radiation
include aluminum. This metal is often used to build spacecraft because it is strong and
lightweight. But, it can only absorb about half of the radiation that hits it. By testing other
materials, scientists will be able to find new ways of making spacecraft. In the future,
new materials may be strong and lightweight like aluminum, but also able to stop more
of the harmful radiation.
2. How does the atmosphere act as an insulator?
The atmosphere protects us from UV and other short wavelength light that would
otherwise do a lot of damage to the DNA of living organisms. Without the atmosphere, it
would get really hot in the day time, and extremely cold at night. The atmosphere is also
important because it contains oxygen, which we and other living organisms breathe. It
also acts as a medium of transport for various chemicals, including, but not limited to,
water (in the form of rain, snow, steam, etc), carbon dioxide and oxygen (for cycling of
these chemicals between plants and animals), and nitrogen (which helps plants grow).
There are also other biogeochemical cycles (cycling of different chemicals) between the
land masses, the oceans, and the atmosphere that are important for the various kinds of
ecosystems around the world.
8. Specific Heat Word Problems
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 Gain = mass * change in temperature * Specific Heat
Heat Gain = 15.75 g * 150 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 = 10.0g * 33°C * 0.90 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 J = 50.0g * (x - 20.0°C) * .50 J/g°C
5275 J = (x - 20.0°C)
211 J = (x - 20.0°C)
X = 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
6.75×104 J = 1500.0 g * 25°C * SH
67500 = 37500 g * SH
1.8 = SH
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 = 100.0 mL * 33°C * 4.18 J/g°C
Heat = 13794 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 = 25.0 g * 130°C * SH
455 J = 3250g°C *n
.14 = x
7. What is the specific heat capacity of silver metal if 55.00 g of the metal absorbs
47.3 calories of heat and the temperature rises 15.0°C?
Heat = mass * change in temperature * Specific Heat
Heat Gain
47.3 cal = 55 g * 15 C * x
47.3 cal = 825x
.05733 = x
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 * .71 C * x
1000 j = 106.5x
9.3897 = x
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 H2O = 4.184 J/g °C)
Heat = mass * change in temperature * Specific Heat
Heat = 20 g * 20 C * 4.184 J/gC
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 H2O = 4.184 J/g °C)
Heat = mass * change in temperature * Specific Heat
Heat = 15 * -25 C * 4.184 J/gC
Heat = 1569 j released
Use this website for examples
http://www.kentchemistry.com/links/Energy/SpecificHeat.htm
Specific Heat Lab
Name: Alissa & Claudia & Grace
Class: S3
Teacher: Lopez
Date: 5/7/18
Investigation Title: How to Calculate Specific Heat
I. Investigation Design
A. Problem Statement:
The purpose of this experiment is to calculate the specific heat of the metals.
B. Hypothesis: (Hint: Something about comparing metals to water - use increase or decrease)
If we heat the metal and record the temperatures, then we will be able to identify the
specific heat.
C. Independent Variable: x Aluminium Copper
Levels of IV
*What metals did you use?
Zinc
D. Dependent Variable:y
Specific Heat
E. Constants:
Heat of the hot plate Amount of water
F. Control:
*What substance makes good control in many labs?
Water
G. Materials: (List with numbers)
1. Hot plate
2. Thermometer
3. Beaker
4. Graduated Cylinder
5. Water
6. Distilled White Vinegar
7. Salt Water
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. - Metal Initial Temp.
8. Use tool 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)
Shiny, small size, heavy, dull colors
B. Quantitative Observations: (Key data)
1. Data Table
Mass Mass Δ Temp Δ Temp Heat Heat Lost Real Specific
Object Metal Water H20 Metal Gain
H20 Metal SH Metal Heat
Copper - 24.3-22.
S3
28.4 100 5 86-24.3 180 180 0.103 .385
Aluminu 19.6 100 26-23.5 75.8-26 250 250 0.256 0.215
m 140 0.0958 0.095
Zinc 29.3 100 25.1-23.7 75-25.1 140
2. Graph - Metal and Specific Heat
*Compare your results to Periodic Table (Think about this graph)
These results relate to the Periodic Table because Copper and Zinc are next to each other while
Aluminum is nearby as well, meaning their specific heats are similar.
3. Calculations - Show examples of how you solved for specific heat (2 or 3 examples)
Aluminum
Heat Gain = m * ΔT * SH
Heat Gain = 100 g * 2.5 C *1 cal/gC
Heat Gain = 250 cal
Heat Lost = m * ΔT * SH
250 cal = 19.6 * 49.8 C * x
250 cal = 9 76.08x
976.08 976.08
.256 cal/gC = x
Zinc
Heat Gain = m * ΔT * SH
Heat Gain = 100 g * 1.3 C * 1 cal/gC
Heat Gain = 130 cal
Heat Lost = m * ΔT * SH
130 cal = 29.3 g * 49.9 C * x
130 cal = 1462.07x
.958 = x
4. Data Analysis/Conclusions
The purpose of this experiment is to calculate the specific heat of the metals.
Our hypothesis, if we heat the metal and record the temperatures, then we will be able to
identify the SH, was correct. After we heated the metal, we successfully calculated a
specific heat number for all of the metals.
5. Research
1. How does Specific Heat relate to a real life application? L and Breezes
Specific Heat relates to many real life applications, one such is land breezes. During the day,
the land, which has a low specific heat and is a poor conductor, heats much quicker than water.
As the land heats up, the air around it heats by conduction and rises, warming the air above the
land by convection.
2. Include 2 sources for evidence
http://cimss.ssec.wisc.edu/wxwise/seabrz.html
http://spmphysics.onlinetuition.com.my/2013/07/phenomena-related-to-specific-heat_4.html
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Grace Cox (Class of 2022) - Blue Science Portfolio #3
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