ii Must Know iii – x Chapter 1 Measurement 1 – 14 NOTES 1 Paper 1 4 Paper 2 9 Reinforcement and Assessment of Science Process Skills for Paper 3 (Practical Test) 13 Chapter 2 Force and Motion I 15 – 36 NOTES 15 Paper 1 17 Paper 2 26 Reinforcement and Assessment of Science Process Skills for Paper 3 (Practical Test) 34 Chapter 3 Gravitation 37 – 48 NOTES 37 Paper 1 40 Paper 2 44 Chapter 4 Heat 49 – 68 NOTES 49 Paper 1 52 Paper 2 60 Reinforcement and Assessment of Science Process Skills for Paper 3 (Practical Test) 66 Chapter 5 Waves 69 – 86 NOTES 69 Paper 1 71 Paper 2 82 Chapter 6 Light and Optics 87 – 106 NOTES 87 Paper 1 90 Paper 2 98 Reinforcement and Assessment of Science Process Skills for Paper 3 (Practical Test) 105 Answers 107 – 126 Contents Contents QBank Physics F4.indd 2 14/01/2022 4:57 PM
MUST KNOW Mnemonics Mnemonics (Chapter 1) 1 @ Pan Asia Publications Sdn. Bhd. Mnemonics (Chapter 5) 7 @ Pan Asia Publications Sdn. Bhd. Mnemonics (Chapter 1) 3 @ Pan Asia Publications Sdn. Bhd. Mnemonics (Chapter 5) 9 @ Pan Asia Publications Sdn. Bhd. Mnemonics (Chapter 2) 5 @ Pan Asia Publications Sdn. Bhd. Mnemonics (Chapter 6) 11 @ Pan Asia Publications Sdn. Bhd. Order of Rainbow Colours Graph Plotting Procedures The Linear Motion Equations of Uniform Acceleration Electromagnetic Spectrum Characteristics of Image Formed by Concave Lens or Convex Mirror • To remember the order of colours in the visible light spectrum, as seen in a rainbow. Red → R Orange → o Yellow → y Green → G. Blue → B Indigo → i Violet → v Roy G. Biv Axes → A Scales → S Plot → P Curve → C Gradient → G Intercept → I ASP C GI Virtual → V Upright → U Diminished → D VUD • In the order of increasing frequency or decreasing wavelength of electromagnetic waves: Mnemonic Electromagnetic Waves Red Radio waves Martians Microwaves Invaded Infrared Venus Visible light Using Ultraviolet X-ray X-Rays Guns Gamma rays (uv ats) u v a t s Linear Motion Equation 3 3 3 3 7 v = u + at 3 3 3 7 3 v2 = u2 + 2as 3 3 7 3 3 s = 1 2 (u + v)t 3 7 3 3 3 s = ut + 1 2 at2 7 : Variable not involved 3 : Variable involved To remember the seven base quantities: Length (l) → l Mass (m) → m Time (t) → t Thermodynamic Temperature (T) → T Electric Current (I) → I Luminous Intensity (Iv ) → I Amount of Substance (n) → n lm2t2In Seven Base Quantities Must Know QBank Physics F4.indd 1 14/01/2022 5:08 PM
MUST KNOW Important Definition Important Definition (Chapter 5) 8 @ Pan Asia Publications Sdn. Bhd. Important Definition (Chapter 1) 2 @ Pan Asia Publications Sdn. Bhd. Important Definition (Chapter 5) 10 @ Pan Asia Publications Sdn. Bhd. Important Definition (Chapter 1) 4 @ Pan Asia Publications Sdn. Bhd. Important Definition (Chapter 6) 12 @ Pan Asia Publications Sdn. Bhd. Important Definition (Chapter 2) 6 @ Pan Asia Publications Sdn. Bhd. Damping and Resonance Physical Quantities Fundamentals of Waves and Oscillations Total Internal Reflection and Critical Angle Experimental Design Inertia Terminology Explanation Physical quantity Must be measurable Base quantity Cannot be defined in terms of other quantities Derived quantity Derived from combinations of base quantities through multiplication or division or both Scalar quantity Has magnitude only Vector quantity Has both magnitude and direction • Oscillation and vibration are repetitive motions about an equilibrium position in a closed path. • Amplitude is the maximum displacement of an oscillating object from its equilibrium position. • Frequency is the number of complete vibrations per second. Unit of frequency is hertz (Hz). • Period is the time taken for one complete oscillation. • Waves are produced when a system oscillates or vibrates in a medium or field. • Inertia of an object refers to the reluctance of the object to change its state of rest or motion due to its mass. • Inertia is non-physical quantity. It is an attribute only. Manipulated Variable (MV) The variable you will change before carrying out the experiment. Responding Variable (RV) The variable you will measure in responding to the change in the MV. Constant Variable (CV) Any other variables which could affect the outcome of the experiment but you set to remain constant throughout the experiment. Example: The simple pendulum experiment MV: Length of pendulum, l = 20.0 cm, 30.0 cm… 70.0 cm RV: Time taken for 20 complete oscillations CV: Mass of pendulum bob • When a ray of light propagates from a denser medium to a less dense medium, total internal reflection is said to occur when the angle is incidence is greater than the critical angle. • The critical angle, c, is the angle of incidence of light, moving from a denser medium towards a less dense medium where the angle of refraction is equal to 90°. n = 1 sin c • Free vibrations are the vibrations of a system at its natural frequency without external disturbance. • Damped vibrations are the vibrations of a system where the amplitude decreases with time due to resistive forces. • Forced vibrations are the vibrations of a system caused by external alternating forces. • When a periodic force is applied to an oscillating system at its natural frequency, the oscillating system is said to be at resonance. Must Know QBank Physics F4.indd 2 14/01/2022 5:08 PM
MUST KNOW Important Diagrams Important Diagrams (Chapter 4) 44 @ Pan Asia Publications Sdn. Bhd. Important Diagrams (Chapter 1) 38 @ Pan Asia Publications Sdn. Bhd. Important Diagrams (Chapter 6) 46 @ Pan Asia Publications Sdn. Bhd. Important Diagrams (Chapter 2) 40 @ Pan Asia Publications Sdn. Bhd. Important Diagrams (Chapter 6) 48 @ Pan Asia Publications Sdn. Bhd. Important Diagrams (Chapter 2) 42 @ Pan Asia Publications Sdn. Bhd. The Heating Curve Interpretation of Graphs Formation of Virtual Images Formation of Image by an Astronomical Telescope Ticker Tape Charts Interpretations of Linear Motion Graphs y is inversely proportional to x: y 1 x y x 0 0 x 1 y or F O F u f I u f C O I F P Conditions: u ˂ f Image Characteristics: Virtual, Upright, Magnified Displacement, s / m Object moving with uniform velocity (a) Object moving with uniform acceleration (b) Object moving with uniform acceleration (c) Time, t / s 0 0 0 Velocity, v / m s-1 Acceleration, a / m s-2 Time, t / s Time, t / s Length/ cm Time/ s Uniform velocity Uniform acceleration Uniform decrease uniformly Time/ s Time/ s Length/ cm Length/ cm Objective lens (L1 ) Eyepiece lens (L2 ) Virtual image at infinity f o f o M = ––f e Fo , I 1 Fe f e Observer L L = f o + f e Temperature Solid Solid and liquid Boiling point Melting point Liquid and gas Liquid Gas Time 0 P Q R S T U Must Know QBank Physics F4.indd 8 14/01/2022 5:09 PM
1 Chapter 1 Measurement NOTES 1.1 Physical Quantities 1. Physics is the study of space, time, matter and energy as well as phenomena happening around us. 2. Measurement plays an important role in investigating natural phenomena and inventing modern equipment to solve problems in our lives. 3. Measurement is a method to determine the value of a physical quantity. The results of accurate measurements enable us to make right decisions. 4. Physical quantities are quantities that can be measured, consists of a numerical magnitude and a unit. Length = 10 m Unit Magnitude Physical quantity 5. All measurement requires a system of units. We always express the result of a measurement as a number (numerical magnitude) multiplied by a unit. The metric system of units considered superior to most other systems of units. Example: Length = 10 m means 10 multiplied by the length of one metre 6. Base quantities are physical quantities that cannot be derived from other physical quantities. These base quantities cannot be defined in terms of more fundamental quantities. Base quantity Symbol Length l Mass m Time t Thermodynamic temperature T Electric current I Luminous intensity Iv Amount of substance n S.I. unit Symbol metre m kilogram kg second s kelvin K ampere A candela cd mole mol 7. Derived quantities are physical quantities that are derived from the mathematical combinations of base quantities through multiplication or division or both. 8. Scalar quantity is a physical quantity that can be expressed in terms of its magnitude only. 9. Vector quantity is a physical quantity that must be expressed in both magnitude and direction. Examples of scalars Distance Density Speed Temperature Time Energy Mass Power Examples of vectors Displacement Momentum Velocity Impulse Acceleration Weight Force Field strength B01 QBank Physics F4.indd 1 10/02/2022 3:44 PM
2 1.2 Scientific Investigation 1. Making an inference means interpreting or explaining factors as a result of an observation. Example: The period of a simple pendulum is affected by its length. 2. Hypothesis is a general statement that attempts to relate two or more variables. Example: The longer the length of a simple pendulum, the longer its period of oscillation. 3. Variable is a physical quantity that must be considered in order to describe an observation. Example: The period of oscillation of a simple pendulum and the length of the simple pendulum. 4. Manipulated variable is a physical quantity whose values must be determined before the experiment is carried out. Example: Length of the simple pendulum. 5. Responding variable is a physical quantity that depends on a manipulated variable and is obtained during the experiment. Example: The period of oscillation. 6. Constant variable is a physical quantity that must be fixed throughout the experiment. Example: mass of pendulum bob, the gravitational acceleration. 7. Checklist of methods for graph plotting (ASPCGI): axes, scale, plot, curve, gradient and intercept. 8. A graph represents the average value of the readings of an experiment and provides a visual relationship between variables under investigation. 9. By analysing information from the graph, we can find data patterns, the relationship between variables involved and to formulate generalisation of a particular principle or law of physics. 10. When a straight line that has a positive gradient and that passes through the origin is obtained, the equation that can be deduced is y = mx. This shows that y is directly proportional to x, and m is the gradient of the line. 0 y x y = mx 11. When a straight line that does not pass through the origin is obtained, the equation that can be deduced is 0 y x y = mx + c This shows that y has a linear relationship with x, and c is the intercept for the line on the y-axis. 12. The gradient of a line is the change in y, Δy, divided by the change in x, Δx. 0 y ∆y ∆x x Gradient, m = ∆y ∆x B01 QBank Physics F4.indd 2 10/02/2022 3:44 PM
4 SOS TIP 1.1 Physical Quantities 1. Physics is a study of A matter and energy B nature and living things C measurements in science D particles and natural phenomena 2. Which of the following is a S.I. base unit? A Joule B Tesla C Newton D Candela PAPER 1 Answer all questions. 3. Which of the following is not a derived quantity? A Power B Charge C Energy D Temperature 4. The statement below refers to All measurement requires a proper system of units for effective communication A metric system B system International C system of scalars and vectors D system of based and derived units CLONE SPM CLONE SPM Question 4: S.I. is System International useful for effective communication. Question 6: 1.0 N kg–1 = 1.0 (kg m s–2) kg–1, hence 1.0 N kg–1 = 1.0 m s–2 5. Which of the marks (3) combination explains the correct base or derived quantity? HOTS Analysing Quantity Magnitude Direction Scalars Vectors A Base 3 3 B Derived 3 3 3 C Base 3 3 3 3 D Derived 3 3 CLONE SPM 6. Metre per second per second (m s–2) is a unit for gravitational strength. Another unit for gravitational strength is newton per kilogram (N kg–1). Which statement is correct? HOTS Applying A 10–1 N kg–1 = 102 cm s–2 B 1.0 N kg–1 = 100 dm s–2 C 102 N kg–1 = 103 mm s–2 D 10 000 N kg–1 = 10 000 m s–2 7. Which of the following list is/are made up of vectors only? I Time, force, luminous intensity II Velocity, momentum, impulsive force III Work, acceleration, amount of substance A II only B II and III only C I, II and III CLONE SPM 8. Which of the following grouping is correct? HOTS Applying A Scalars: Time Distance Work done Mass of apple B Derived quantities: Speed Weight Volume of gas Thermodynamic temperature B01 QBank Physics F4.indd 4 10/02/2022 3:44 PM
5SOS TIPC Vectors: Force Velocity Acceleration Electrical power D Base quantities: Length Area Electric current Density of liquid 9. Diagram 1 shows both the imperical and metric scales enclaved on a ruler. Which of the following grouping shows metric units only? HOTS Applying Diagram 1 A gram inch mole yard B liter mile foot psi C centimeter candela calorie second D ampere pascal watt ohm 10. Suppose the three base standards of the metric system were length, density, and time rather than length, mass, and time. The standard of density in this system is to be defined as that of water. What is the relationship of mass in terms of the new base standards? HOTS Analysing A rL3 B LT3 C r3 L D 3rLT 11. What are the major concerns if length, density and time were taken as new base standards? HOTS Analysing I The results of measurements are not reproducible II No standard procedure for measuring density of a material III Difficulties in preparation of the standard for density of a selected material A III only B II and III C I, II and III 1.2 Scientific Investigation 12. Diagram 2 shows a graph of relationship between p and q. HOTS Applying p q b a 0 (0, c) Diagram 2 Which of the following is incorrect? A The gradient is a b B p increases linearly with q C The equation is q = a b p + c D When q = 1 then p = a b + c Question 9: Only the grouping of ampere, pascal, watt and ohm are metric units. Question 10: Use r = mL–3 Question 12: Use y = mx + c B01 QBank Physics F4.indd 5 10/02/2022 3:44 PM
6 SOS TIP 13. Which of the following graph shows P varies non-linearly with V? HOTS Applying A P V B P V C P V D P V 14. Diagram 3 shows a graph of relationships between two physical quantities, V and I for two different materials of R and S. Which of the following statement is most appropriate? HOTS Analysing V R S 0 I Diagram 3 A The gradient of material R is greater than that of S B Both materials R and S have a linear relationship of V against I C Material R possesses greater rate of direct proportionality than S D As V increases, the value of I must also increase for both materials R and S 15. Diagram 4 shows a graph of p against q for two different media, X and Y. p q Medium X Medium Y Diagram 4 EX : q-intercept of medium X EY : q-intercept of medium Y rX : graph gradient of medium X r Y : graph gradient of medium Y Which pair is correct? HOTS Analysing p-intercept Graph gradient A EX , EY rX . rY B EX . EY rX , rY C EX , EY rX , rY D EX . EY rX . rY 16. Graph of y against x in Diagram 5 shows the inverse proportionality relationship between physical quantities of y and x. What is the value of y when x = 10? HOTS Applying 50 40 30 20 10 0 1 25 2.4 2 3 4 5 y x Diagram 5 A 6 C 36 B 12 D 60 Question 13: Answer C shows a curve with positive gradient and passing through the origin. Answer D shows an inverse-proportionality relationship. B01 QBank Physics F4.indd 6 10/02/2022 3:44 PM
98 SOS TIP PAPER 2 Section A Answer all questions. 1. Diagram 1 shows a surgeon performing microsurgery. She needs a sharp, magnified view of the surgical site. She’s wearing glasses with magnifying lenses. Diagram 1 (a) Name the type of lenses she’s wearing. [1 mark] (b) What is the optical phenomena occurred in the lenses? [1 mark] (c) Draw a ray diagram to show the formation of the image for the surgical site. [2 marks] (d) The surgeon does not wish to strain her eyes while performing the microsurgery. Where should be the exact position of the surgical site from her (i) magnifying lenses (ii) eyes? HOTS Analysing [2 marks] 2. Diagram 2.1 shows how a ray of light passes through a glass block. Air Glass Diagram 2.1 (a) (i) Draw and label the normal, the refracted ray, the angle of incidence and the angle of refraction in Diagram 2.1. [2 marks] Question 1: (d) A virtual image with a large angular size that is infinitely far away and the distance from magnifier to eye is not that crucial. B06 QBank Physics F4.indd 98 10/02/2022 3:49 PM
102 SOS TIP (c) Why is an image formed by a parabolic mirror sharper than the image of the same object formed by a concave spherical mirror? HOTS Analysing [3 marks] Section B Answer all questions. 6. (a) In Diagram 6, a real inverted image I of an object O is formed by a particular lens (not shown); the object–image separation is d = 60.0 cm, measured along the central axis of the lens. The image is just half the size of the object. O Lens here d Axis I Diagram 6 (i) What kind of lens must be used to produce this image? (ii) How far from the object must the lens be placed? (iii) What is the focal length of the lens? (iv) What is the other position of lens that can be used to produce a magnified image? Explain your answers clearly. HOTS Analysing [8 marks] (b) A compound microscope contains an objective lens and an eyepiece lens. The focal length of the objective lens is f o and the focal length of the eyepiece lens is f e . You are assigned to study the suitable ways to build a compound microscope with maximum magnification. Table 1 shows various arrangement for the lenses. Table 1 Aspect Arrangement Object distance, uo from the objective lens Comparison of fo and fe Distance between objective lens and eyepiece, d Distance between the image formed by the objective lens and the eyepiece, ui W uo , fo f o , f e d . (f o + f e ) ui , f e X uo . 2f o f o . f e d = (f o + f e ) ui . f e Y f o , uo , 2 fo f o , f e d . (f o + f e ) ui , f e Z uo = f o f o . f e d = (f o + f e ) ui = f e (i) Choose the most suitable arrangement and provide reasons for your choice. HOTS Evaluating [10 marks] (ii) Apart of the aspects given in Table 1, suggest another one factor for better quality of compound microscope. Give a reason. HOTS Creating [2 marks] Question 5: (c) All parallel rays converge at a parabolic mirror’s focal point. The focal point is sharp. Question 6: (b) The refractive indices of the objective lens and eyepiece may affect the design of the microscope. The range of wavelengths for the light source also can affect the quality of image formed. B06 QBank Physics F4.indd 102 10/02/2022 3:49 PM
104 SOS TIP Section C Answer all questions. 8. When light rays encounter curved surfaces between two media, images can be formed by either reflection or refraction due to these surfaces. We can design mirrors and lenses to form images with desired characteristics. (a) Explain how does a curved surface change the direction of light? HOTS Applying [2 marks] (b) Diagram 8.1 shows the design of an oven made by a student for boiling soup using solar energy. Diagram 8.1 You are required to suggest new design of an oven so that the soup in the pot boils in a shorter time. In your explanation, emphasize on the following aspects: (i) Size of the oven (ii) Shape of the oven (iii) Position of the pot (iv) The type of surface for the oven (v) The variation of the orientation for the oven with time HOTS Creating [10 marks] (c) In Diagram 8.2, an object is placed in front of a converging lens at a distance equal to twice the focal length f 1 of the lens. On the other side of the lens is a concave mirror of focal length f 2 separated from the lens by a distance 2(f 1 + f 2 ). Light from the object passes rightward through the lens, reflects from the mirror, passes leftward through the lens, and forms a final image of the object. f 1 O 2f 1 2(f 1 + f 2 ) f 2 Diagram 8.2 What are (i) the distance between the lens and that final image, (ii) the overall lateral magnification M of the object and (iii) the characteristics of the final image? HOTS Evaluating [8 marks] Question 8: (c) First, the convex lens form a real image of the object, I 1 at a distance 2f 1 to the right of the lens. This is 2(f 1 + f 2 ) – 2f 1 = 2f 2 in front of the concave mirror. The subsequent image formed by the concave mirror, I 2 is located at a distance 2f 2 to the left of the mirror. This is 2(f 1 + f 2 ) – 2f 2 = 2f 1 to the right of the convex lens. The final image, I 3 is formed at a distance 2f 1 to the left of the lens. [You may construct a ray diagram to verify these] B06 QBank Physics F4.indd 104 10/02/2022 3:49 PM
105SOS TIPQuestion 1: (b) Make sure that the derived quantities of uv and D must have consistent number of decimal places. (e) Make sure the object, the optical centre of the lens and the centre of the screen were located on the principal axis of the lens. The eye position must be vertically above the scale of the metre rule when taking readings to avoid parallax errors. Reinforcement and Assessment of Science Process Skills for Paper 3 (Practical Test) 1. In this experiment, you will determine the focal length, f of a lens. Carry out the following instructions, referring to Diagram 1. X wire screen Lamp Lens D u v i Screen Diagram 1 (a) Place the centre of the lens at a distance, u = 15.0 cm from the illuminated X wire. Place the screen close to the lens and move it away from the lens until a sharply-focused image is formed on the screen. • Measure the distance, v from the centre of the lens to the screen. Record v in Table 1. • Calculate uv and record the result in the table. • Measure and record the distance D from the illuminated X wire to the screen in the table. (b) Repeat the steps in (a) with the lens at a distance u = 20.0 cm, 25.0 cm, 30.0 cm and 35.0 cm from the illuminated X wire. Record all the readings in the table. [6 marks] Table 1 u / cm v / cm uv / cm2 D / cm 15.0 20.0 25.0 30.0 35.0 (c) Based on the information and observation: (i) identify the manipulated variable, (ii) identify the responding variable. [2 marks] (d) Plot a graph of uv (y-axis) against D (x-axis). Start your axes from the origin (0,0). Draw a best-fit line. [3 marks] (e) (i) Based on the graph drawn in (d), determine the value of the focal length of the lens. [2 marks] (ii) State two precautions that you took in this experiment in order to obtain reliable readings. [2 marks] B06 QBank Physics F4.indd 105 10/02/2022 3:49 PM
106 SOS TIP If you are unable to carry out the experiment described, you can answer this question by using the data obtained as shown in Table 2. Table 2 u/cm v/cm u/cm v/cm 15.0 26 27 28 29 30 31 Screen 30.0 11 12 13 14 15 16 Screen 20.0 16 17 18 19 20 21 Screen 35.0 10 11 12 13 14 15 Screen 25.0 13 14 15 16 17 Screen • Experiment must be carried out in darkened room. • Lens, screen and object must be on a same straight line. • When the object is moving further away from the lens, the size and the position of the image both change and you need to move the screen nearer to get a clear and sharp image again. B06 QBank Physics F4.indd 106 10/02/2022 3:49 PM
107 Answers Chapter 1 CHAPTER 1 Paper 1 1. A Physics is the study of matter and energy as well as phenomena happening around us. 2. D Candela (cd) is the base unit for luminous intensity. 3. D Thermodynamic temperature is a base quantity. 4. B S.I. is a worldwide standardisation of measurement units that has simplified the work in science, sports, commerce, medicine and other fields. 5. C Both base and derived quantities may be scalars or vectors. Vector has both magnitude and direction. 6. D 1 N kg–1 = 1 m s–2, hence 10 000 N kg–1 = 10 000 m s–2 . 7. A All three: velocity, momentum and impulsive force have both magnitude and direction. 8. A All the four quantities do not have direction. 9. D Ampere, pascal, watt and ohm are metric units. 10. A r = m L–3, hence m = rL3 . 11. C All true 12. C The correct equation is p = a b q + c. 13. C Curve with positive gradient and passing through the origin. Answer D shows an inverse-proportionality relationship. 14. A The R line has steeper slope than S. 15. A The X line has steeper slope than Y but at p = 0, line Y is above X. 16. A Inverse proportionality: x1 y1 = x2 y2 , 2.4 × 25 = 10 × y2 y2 = 6 17. C Square both sides, r2 = ( π ß ) 2 s, if r2 is plotted against s, the gradient is ( π ß ) 2 . 18. B A graph represents the average value of the readings of an experiment and provides a visual relationship between variables under investigation. 19. B A line of best fit is a straight line drawn through the maximum number of points and balancing about an equal number of points above and below the line. 20. A Making an inference means interpreting or explaining factors as a result of an observation for a phenomenon. The ultimate goal of a problem statement is to transform a generalized problem into a targeted, well-defined problem; one that can be resolved through scientific research. 21. A Using y = sx + c, substitute x with V, y with U, s = m n , and c is U-intercept = m and then rearrange to make V as a subject in the equation. 22. D When we divide the measured time by 20, the inaccuracy associated with period T due to human reaction will be only 1 20 of the human reaction time i.e 0.015 to 0.025 s. 23. C The Earth is not a perfect sphere – it’s slightly flattened at the poles and bulges out near the equator, so points near the equator are farther from the center of mass. The distance between the centers of mass of two objects affects the gravitational force between them, so the force of gravity on an object is smaller at the equator compared to the poles. 24. C All true except T is directly proportional to l. The correct relationship is T2 is directly proportional to l. 25. C All true except m is directly proportional to T. The correct relationship is T2 is directly proportional to m. 26. D A straight line drawn through the maximum number of experimental points may not be the best fitted line. Paper 2 Section A 1. (a) Base quantity is physical quantity that cannot be derived from other physical quantities. (b) (i) Base quantity Derived quantity Time Temperature Power (ii) Metric system Imperial system watt °F 2. (a) (i) Distance (ii) Force, charge (any one) (iii) Force (b) Unit for k = Fr2 Qq = kg m s–2 × m2 (A s × A s) = kg m3 s–4 A–2 3. (a) (i) Average time, t = t 2 + t 1 2 = 22.22 + 22.13 2 = 22.18 s (ii) To reduce the inaccuracy due to human reaction time. (iii) • Set the simple pendulum swings with small amplitude • Make sure the oscillations are on a vertical plane only. (b) (i) T = 22.18 20 = 1.109 s (ii) l = ( g 4π2 )T2 = ( 981 4π2 ) × (1.109)2 = 30.56 cm (iii) The time taken for 20 swings will be much longer (roughly 2.5 times) because the value of g on the Moon surface is 6 times smaller than that on the Earth. Answer QBank Physics F4.indd 107 10/02/2022 4:03 PM
108 Chapter 1 – Chapter 2 4. (a) m = r V, l = 3 !V (b) • No measuring instrument can measure density and volume accurately. • No suitable object for standard density and standard volume. • Units for derived quantity become very complex. • Hinder effective communication among physicists. 5. (a) Draw graph of V against x. Extrapolate it to find V0 when x = 0. V0 is 46 L. (b) Using interpolation method V is 41 L when x = 50 km, hence the petrol consumption is V – V0 = 46 – 41 = 5 L (c) Distance, x / km 40 60 80 100 120 140 160 180 200 Volume of petrol, V / L 42.60 40.05 37.93 35.80 33.25 31.55 30.28 27.30 25.60 (d) Graph of remaining volume of petrol, V against distance, x 10 0 20 40 60 80 100 120 140 160 180 200 20 30 40 50 Remaining volume of petrol, V / L x / km Paper 3 1. (a) Measure l 1 and l 2 and then taking average. l 1 l 2 l 2 l 1 l l 2 Clamp = + Centre of bob (b) l / cm t / s T / s T2 / s2 20.0 17.65 0.833 0.780 30.0 22.15 1.108 1.228 40.0 25.00 1.250 1.563 50.0 27.95 1.398 1.954 60.0 30.80 1.540 2.372 (c) (i) The manipulated variable: length of pendulum, l (ii) The responding variable: the period T of the pendulum (d) Graph of T2 against l 10 0 0.4 0.8 1.2 1.6 2.0 2.4 2.8 20 30 40 50 60 70 80 I / cm T2 / s2 (e) Gradient, s = 2.38 – 0 60 – 0 = 0.0397 s2 cm–1 g = 4π2 s = 994 cm s–2 CHAPTER 2 Paper 1 1. D Distance is the total length travelled by the security personnel = 5 + 7 + 5 + 10 + 10 + 10 + 10 = 57 m. Displacement is the distance travelled in a specified direction PQ = 7 + 10 +10 = 27 m. 2. A Not sufficient information to check whether the object moves with constant velocity or not (the dots do not display consistent equal spacing pattern). 3. A u = 0.2 cm 0.02 s = 10 cm s–1 v = 1.4 cm 0.04 s = 35 cm s–1 ∆ t = 4.5 × 0.02 = 0.09 s (From 1st the mid-point to the end mid-point) Acceleration = 35 – 10 0.09 s = 278 cm s–2 4. D 10 ticks = 0.2 s u = 4 cm 0.2 s = 20 cm s–1 v = 24 cm 0.2 s = 120 cm s–1 ∆ t = (6 – 1) × 0.2 s = 1 s Acceleration = (120 – 20) cm s–1 1 s = 100 cm s–2 Answer QBank Physics F4.indd 108 10/02/2022 4:03 PM
109 5. C When an object is rotated at a certain uniform speed, though the speed is uniform, the direction of motion of the object keeps changing. Hence, acceleration is acting on the object. 6. B s = 1 2 (u + v)t 1.5 = 1 2 (0 + 20)t t = 0.15 s 7. B v2 = u2 + 2as 352 = 0 + 2(4)s, s = 153.1 m Hence, minimum runway is 154 m long 8. B v = 600 m 5 × 5 s = 24 m s–1 (6 drops of oil = 5 time intervals only) 9. A Average velocity = Total displacement Total time taken = 10 20 = 0.5 m s–1 10. D Displacement measures the shortest distance travelled between the starting point and the ending point. 11. C The gradient at PQ is increasing with time, hence the object’s acceleration is increasing. The gradient at ST is zero, hence it’s moving with uniform velocity. 12. B Area of trapezium = 1 2 (20 + 8)v = 56 v = 112 28 = 4.0 m s–1 13. B The acceleration of cyclists is positive in the beginning then zero and finally negative. 14. B A steady speed means that the speed of the toy car remains the same during the motion. 15. B The gradient of the graph from Q to S is increasing and then decreasing. (You may draw tangents along the curve Q to S to confirm this) 16. B s = ut + 1 2 gt2 = 0 + 1 2 (9.81)(2.12)2 = 22.05 m 17. D No air on the surface of the Moon. Objects of different masses fall with the same acceleration if air resistance does not exist. Hence, they will reach the floor at the same time. 18. C Gravitational acceleration is constant near the surface of the Earth. 19. C s = ut + 1 2 gt2 0 + 1 2 (9.81)t 2 = 125 m t = 5.05 s 20. A By using v2 = u2 – 2gs At maximum height, v = 0 Hence, s = u2 2g s = 252 2 × 9.81 s = 31.9 m 21. D Both R and S are heavy objects and they will travel with same variation of velocity with time. 22. D This is a non-free fall motion because of the effect of air resistance and parachute action on the parachutist. Hence, velocity, acceleration and momentum are not constant. 23. D Objects of different masses fall with the same acceleration if air resistance does not exist (vacuum cylinder). Hence, they will reach the floor at the same time. 24. D Apples of different masses fall with the same acceleration under free fall condition (vacuum means no air resistance). Answer C not correct because no measurement was made. 25. A Inertia is the tendency of an object to remain at rest or, if moving, to continue its motion in a straight line at uniform velocity. The concept of inertia is explained in Newton’s First Law of Motion. 26. A The larger the mass of an object, the larger the inertia of the object. 27. A The loaded supertanker is massive and has huge amount of inertia. Hence, it’s very difficult to change the states of motion. 28. D Inertia is the resistance of an object to change its state of motion. Inertia is non-physical quantity. Mass is a measure of inertia. 29. C There may be external forces acting on the object but they are well balanced. Due to F = ma, a = 0 (uniform velocity) when ∑F = 0. 30. C Newton’s Third Law of Motion states that for every force there is an opposite and equivalent force against it. 31. B Objects with larger momentum are more difficult to stop. 32. D When two or more objects act on each other, their total momentum remains constant, provided there are no external forces acting on the system. 33. C m1 v1 + m2 v2 = m1 u1 + m2 u2 10 1 000 v + 0.1 × (–0.05) = 0 v = 0.5 m s–1 34. C If body A exerts a force FAB on body B, then body B will exert an equal and opposite force FBA on body A. 35. D All the statements regarding action and reaction forces are true. 36. C Momentum, p = mv, v can be increased by increasing p. 37. A m1 v1 + m2 v2 = m1 u1 + m2 u2 (1 000 × 5.0) + (800 × 2.0) = (1 000 × 3.4) + 800v v = 4 m s–1 38. C Most of the weight of the rocket is the weight of the propellants. In order to lighten the weight of the vehicle to achieve higher acceleration, most launchers discard a portion of the vehicle in a process called staging. 39. D Recall the definition of acceleration. It’s the rate change of velocity. 40. C Force will not change the inertia of an object 41. C a = v – u t = 30 5 = 6 m s–2 F = ma = 1 200 × 6 = 7 200 N Chapter 2 Answer QBank Physics F4.indd 109 10/02/2022 4:03 PM