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Secondary 3 Physics Semestral Assessment 2 (End of Year) Paper 1
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Questions
TuitionGoWhere Practice Paper – Physics Secondary 3
TuitionGoWhere Secondary School (AI)
Subject: Physics
Level: Secondary 3
Paper: SA2 – Version 1
Duration: 1 hour 30 minutes
Total Marks: 60
Name: _________________________
Class: _________________________
Date: _________________________
Instructions to Candidates
- This paper consists of three sections: Section A, Section B, and Section C.
- Answer all questions.
- Write your answers in the spaces provided.
- Show all working clearly for calculation questions. Marks are awarded for correct method, even if the final answer is wrong.
- Take g = 10 m/s² unless otherwise stated.
- The number of marks is given in brackets [ ] at the end of each question or part question.
- You are advised to spend about 30 minutes on Section A, 30 minutes on Section B, and 30 minutes on Section C.
Section A: Multiple Choice (10 marks)
Answer all questions. Circle the letter of the correct answer. Each question carries 1 mark.
1. A car accelerates uniformly from rest to 20 m/s in 5 seconds. What is its acceleration?
A. 2 m/s²
B. 4 m/s²
C. 5 m/s²
D. 10 m/s²
[1]
2. A block of mass 5 kg is pulled along a rough horizontal surface at constant speed by a horizontal force of 15 N. What is the magnitude of the frictional force acting on the block?
A. 0 N
B. 15 N
C. 35 N
D. 50 N
[1]
3. Which of the following is a vector quantity?
A. Mass
B. Speed
C. Energy
D. Weight
[1]
4. A student applies a force of 40 N to push a box a distance of 3 m along a horizontal floor. The box moves at constant speed. How much work is done by the student on the box?
A. 0 J
B. 13.3 J
C. 40 J
D. 120 J
[1]
5. An object of mass 2 kg is dropped from a height of 5 m. What is its kinetic energy just before it hits the ground? (Ignore air resistance.)
A. 10 J
B. 20 J
C. 50 J
D. 100 J
[1]
6. A uniform metre rule is pivoted at its 50 cm mark. A 2 N weight is hung at the 20 cm mark. At which mark must a 4 N weight be hung to balance the rule?
A. 35 cm
B. 65 cm
C. 80 cm
D. 95 cm
[1]
7. A force of 100 N acts on an area of 0.5 m². What is the pressure exerted?
A. 50 Pa
B. 100 Pa
C. 150 Pa
D. 200 Pa
[1]
8. The gravitational field strength on the Moon is about 1.6 N/kg. What is the weight of a 10 kg object on the Moon?
A. 1.6 N
B. 6.25 N
C. 10 N
D. 16 N
[1]
9. A car of mass 800 kg accelerates at 2.5 m/s². What is the resultant force acting on the car?
A. 320 N
B. 800 N
C. 2000 N
D. 3200 N
[1]
10. A skydiver of mass 70 kg reaches terminal velocity. What is the magnitude of the air resistance acting on the skydiver at this point?
A. 0 N
B. 70 N
C. 350 N
D. 700 N
[1]
Section B: Structured Questions (30 marks)
Answer all questions in the spaces provided.
11. A student investigates the motion of a trolley on a frictionless track. The velocity-time graph below shows the motion of the trolley over 10 seconds.
Velocity (m/s)
^
12 | ___________
| / \
| / \
6 | / \
| / \
| / \
0 |____/ \____
|____|____|____|____|____|____|____> Time (s)
0 2 4 6 8 10 12
(a) Describe the motion of the trolley between:
- 0 s and 4 s
- 4 s and 8 s
- 8 s and 10 s
[3]
(b) Calculate the acceleration of the trolley during the first 4 seconds.
[2]
(c) Calculate the total distance travelled by the trolley in the 10 seconds.
[3]
12. A wooden crate of mass 25 kg is pulled up a rough inclined plane at constant speed by a force of 180 N applied parallel to the plane. The crate moves a distance of 4.0 m along the plane and rises through a vertical height of 1.6 m.
(a) Calculate the work done by the applied force.
[2]
(b) Calculate the gain in gravitational potential energy of the crate.
[2]
(c) Calculate the energy dissipated as heat due to friction.
[2]
(d) Calculate the magnitude of the frictional force acting on the crate.
[2]
13. A ball of mass 0.5 kg is thrown vertically upwards with an initial speed of 12 m/s. Ignore air resistance.
(a) Calculate the maximum height reached by the ball.
[3]
(b) State the acceleration of the ball at its highest point. Explain your answer.
[2]
(c) Calculate the kinetic energy of the ball when it has fallen halfway back to its launch point from its maximum height.
[3]
14. A uniform plank of length 3.0 m and weight 200 N is supported by two trestles placed at its ends. A painter of weight 600 N stands on the plank at a distance of 1.0 m from the left end.
(a) Draw a diagram showing all the forces acting on the plank.
[2]
(b) By taking moments about the left trestle, calculate the upward force exerted by the right trestle on the plank.
[3]
(c) Calculate the upward force exerted by the left trestle on the plank.
[1]
Section C: Data-Based and Application Questions (20 marks)
Answer all questions in the spaces provided.
15. A student investigates the relationship between force and extension for a spring. The results are shown in the table below.
| Force (N) | 0 | 1.0 | 2.0 | 3.0 | 4.0 | 5.0 | 6.0 |
|---|---|---|---|---|---|---|---|
| Extension (cm) | 0 | 2.5 | 5.0 | 7.5 | 10.0 | 13.0 | 16.5 |
(a) Plot a graph of force (y-axis) against extension (x-axis) on the grid below. Draw a best-fit line.
[4]
Force (N)
^
7 |
|
6 |
|
5 |
|
4 |
|
3 |
|
2 |
|
1 |
|
0 |________________________________> Extension (cm)
0 2 4 6 8 10 12 14 16 18
(b) Using your graph, determine the spring constant of the spring within the linear region.
[2]
(c) State the extension at which the spring no longer obeys Hooke's Law. Explain how you identified this from the graph.
[2]
(d) Calculate the elastic potential energy stored in the spring when the extension is 10.0 cm.
[2]
16. A hydraulic lift is used to raise a car of mass 1200 kg. The lift consists of a small piston of area 0.02 m² and a large piston of area 0.50 m².
(a) State the principle that explains how a hydraulic lift works.
[1]
(b) Calculate the weight of the car.
[1]
(c) Calculate the minimum force that must be applied to the small piston to lift the car.
[3]
(d) The small piston is pushed down by 0.25 m. Calculate the distance the large piston rises.
[2]
17. A student drops a stone from a bridge into a river 20 m below. She measures the time taken for the stone to hit the water as 2.2 s. She knows that the actual acceleration due to gravity is 10 m/s².
(a) Calculate the theoretical time the stone should take to fall 20 m, assuming no air resistance.
[2]
(b) Suggest a reason why the measured time is longer than the theoretical time.
[1]
(c) Using the measured time, calculate the average acceleration of the stone during its fall.
[2]
(d) The stone has a mass of 0.2 kg. Calculate the average air resistance acting on the stone during its fall.
[3]
END OF PAPER
Answers
TuitionGoWhere Practice Paper – Physics Secondary 3
SA2 – Version 1: Answer Key and Marking Scheme
Section A: Multiple Choice (10 marks)
| Question | Answer | Explanation |
|---|---|---|
| 1 | B | a = (v - u)/t = (20 - 0)/5 = 4 m/s² |
| 2 | B | At constant speed, net force = 0. Frictional force = applied force = 15 N |
| 3 | D | Weight is a force and has both magnitude and direction. Mass, speed, and energy are scalars. |
| 4 | D | W = F × d = 40 × 3 = 120 J |
| 5 | D | GPE at top = mgh = 2 × 10 × 5 = 100 J. By conservation of energy, KE at bottom = 100 J |
| 6 | B | Taking moments about pivot: 2 × (50 - 20) = 4 × (x - 50). 60 = 4x - 200. 4x = 260. x = 65 cm |
| 7 | D | P = F/A = 100/0.5 = 200 Pa |
| 8 | D | W = mg = 10 × 1.6 = 16 N |
| 9 | C | F = ma = 800 × 2.5 = 2000 N |
| 10 | D | At terminal velocity, air resistance = weight = mg = 70 × 10 = 700 N |
Total: 10 marks
Section B: Structured Questions (30 marks)
Question 11 (8 marks)
(a) Description of motion: [3 marks]
- 0 s to 4 s: The trolley accelerates uniformly from rest to 12 m/s. [1 mark]
- 4 s to 8 s: The trolley moves at constant velocity of 12 m/s. [1 mark]
- 8 s to 10 s: The trolley decelerates uniformly from 12 m/s to rest. [1 mark]
(b) Acceleration during first 4 seconds: [2 marks]
- a = (v - u)/t = (12 - 0)/4 = 3 m/s² [1 mark for formula/substitution, 1 mark for correct answer with unit]
(c) Total distance travelled: [3 marks]
- Distance = area under velocity-time graph
- 0-4 s: Area of triangle = ½ × 4 × 12 = 24 m [1 mark]
- 4-8 s: Area of rectangle = 4 × 12 = 48 m [1 mark]
- 8-10 s: Area of triangle = ½ × 2 × 12 = 12 m
- Total distance = 24 + 48 + 12 = 84 m [1 mark for correct total]
Question 12 (8 marks)
(a) Work done by applied force: [2 marks]
- W = F × d = 180 × 4.0 = 720 J [1 mark for formula, 1 mark for correct answer with unit]
(b) Gain in gravitational potential energy: [2 marks]
- GPE = mgh = 25 × 10 × 1.6 = 400 J [1 mark for formula, 1 mark for correct answer with unit]
(c) Energy dissipated as heat due to friction: [2 marks]
- Energy dissipated = Work done by applied force - Gain in GPE
- = 720 - 400 = 320 J [1 mark for method, 1 mark for correct answer with unit]
(d) Magnitude of frictional force: [2 marks]
- Work done against friction = Frictional force × distance
- 320 = f × 4.0
- f = 320/4.0 = 80 N [1 mark for method, 1 mark for correct answer with unit]
Question 13 (8 marks)
(a) Maximum height reached: [3 marks]
- At maximum height, v = 0
- Using v² = u² + 2as: 0 = 12² + 2(-10)h [1 mark for correct equation]
- 0 = 144 - 20h
- 20h = 144
- h = 7.2 m [1 mark for correct answer]
- [1 mark for correct unit]
(b) Acceleration at highest point: [2 marks]
- Acceleration = 10 m/s² downwards [1 mark]
- Explanation: The only force acting on the ball is its weight (gravity), so the acceleration is always g = 10 m/s² downwards, even at the highest point where velocity is momentarily zero. [1 mark]
(c) Kinetic energy when halfway back: [3 marks]
- Maximum height = 7.2 m, so halfway = 3.6 m from maximum height
- Height fallen = 3.6 m
- Loss in GPE = mgh = 0.5 × 10 × 3.6 = 18 J [1 mark]
- Initial KE at launch = ½mv² = ½ × 0.5 × 12² = 36 J [1 mark]
- By conservation of energy: KE at halfway = Initial KE - GPE at that point
- Alternatively: KE gained = GPE lost during fall = 18 J
- KE at halfway point = 18 J [1 mark for correct answer with unit]
Question 14 (6 marks)
(a) Diagram showing forces: [2 marks]
- Forces to show: Weight of plank (200 N) acting at centre (1.5 m from either end) [0.5 mark]
- Weight of painter (600 N) acting 1.0 m from left end [0.5 mark]
- Upward reaction force at left trestle (R₁) [0.5 mark]
- Upward reaction force at right trestle (R₂) [0.5 mark]
(b) Upward force by right trestle: [3 marks]
- Taking moments about left trestle:
- Clockwise moments = Anticlockwise moments
- (200 × 1.5) + (600 × 1.0) = R₂ × 3.0 [1 mark for correct moment equation]
- 300 + 600 = 3R₂
- 900 = 3R₂
- R₂ = 300 N [1 mark for correct answer]
- [1 mark for correct unit]
(c) Upward force by left trestle: [1 mark]
- Total upward forces = Total downward forces
- R₁ + R₂ = 200 + 600
- R₁ + 300 = 800
- R₁ = 500 N [1 mark for correct answer with unit]
Section C: Data-Based and Application Questions (20 marks)
Question 15 (10 marks)
(a) Graph plotting: [4 marks]
- Correct axes labels with units: Force (N) on y-axis, Extension (cm) on x-axis [1 mark]
- Appropriate scales chosen [1 mark]
- All 7 points plotted correctly [1 mark]
- Best-fit straight line through origin for points up to 4.0 N, then curve [1 mark]
(b) Spring constant from linear region: [2 marks]
- Spring constant k = F/x
- Using point from linear region, e.g., (5.0 cm, 2.0 N)
- k = 2.0/0.050 = 40 N/m [1 mark for method, 1 mark for correct answer with unit]
- Note: Must convert cm to m. Accept 0.4 N/cm.
(c) Extension at limit of proportionality: [2 marks]
- Extension = 10.0 cm (or between 10.0 cm and 13.0 cm) [1 mark]
- Explanation: Beyond this point, the graph curves and the extension is no longer directly proportional to the force. The points deviate from the straight line. [1 mark]
(d) Elastic potential energy at 10.0 cm extension: [2 marks]
- EPE = ½Fx = ½ × 4.0 × 0.10 = 0.20 J [1 mark for formula, 1 mark for correct answer with unit]
- Alternative: EPE = ½kx² = ½ × 40 × (0.10)² = 0.20 J
Question 16 (7 marks)
(a) Principle of hydraulic lift: [1 mark]
- Pascal's Principle: Pressure applied to an enclosed fluid is transmitted equally and undiminished to all parts of the fluid and the walls of the container. [1 mark]
(b) Weight of the car: [1 mark]
- W = mg = 1200 × 10 = 12,000 N [1 mark for correct answer with unit]
(c) Minimum force on small piston: [3 marks]
- Pressure on large piston = Force/Area = 12,000/0.50 = 24,000 Pa [1 mark]
- By Pascal's Principle, pressure on small piston = 24,000 Pa [1 mark]
- Force on small piston = Pressure × Area = 24,000 × 0.02 = 480 N [1 mark for correct answer with unit]
(d) Distance large piston rises: [2 marks]
- Volume of fluid displaced by small piston = Volume of fluid raising large piston
- A₁d₁ = A₂d₂
- 0.02 × 0.25 = 0.50 × d₂ [1 mark for correct equation]
- d₂ = (0.02 × 0.25)/0.50 = 0.01 m = 1.0 cm [1 mark for correct answer with unit]
Question 17 (8 marks)
(a) Theoretical time of fall: [2 marks]
- Using s = ut + ½at²: 20 = 0 + ½ × 10 × t² [1 mark for correct equation]
- 20 = 5t²
- t² = 4
- t = 2.0 s [1 mark for correct answer with unit]
(b) Reason for longer measured time: [1 mark]
- Air resistance acts on the stone, opposing its motion and reducing its acceleration, so it takes longer to fall. [1 mark]
- Accept any valid reason related to air resistance or experimental error.
(c) Average acceleration from measured time: [2 marks]
- Using s = ut + ½at²: 20 = 0 + ½ × a × (2.2)² [1 mark for correct substitution]
- 20 = ½ × a × 4.84
- 20 = 2.42a
- a = 20/2.42 = 8.26 m/s² ≈ 8.3 m/s² [1 mark for correct answer with unit]
(d) Average air resistance: [3 marks]
- Weight of stone = mg = 0.2 × 10 = 2.0 N [1 mark]
- Resultant force = ma = 0.2 × 8.26 = 1.652 N [1 mark]
- Weight - Air resistance = Resultant force
- 2.0 - R = 1.652
- R = 2.0 - 1.652 = 0.348 N ≈ 0.35 N [1 mark for correct answer with unit]
Mark Allocation Summary
| Section | Questions | Marks |
|---|---|---|
| A: Multiple Choice | 1–10 | 10 |
| B: Structured | 11–14 | 30 |
| C: Data-Based & Application | 15–17 | 20 |
| Total | 60 |
End of Answer Key