QSS 2024 4E Physics Prelim P2

NAME: CLASS: INDEX NO: QUEENSWAY SECONDARY SCHOOL PRELIMINARY EXAMINATION 2024 SECONDARY 4 EXPRESS PHYSICS 6091/02 Paper 2 Theory 22 August 2024 1 hour 45 minutes Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, class and index number on all the work you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Section A: Answer all questions. Write your answers in the spaces provided. Section B: Answer one question. Write your answers in the spaces provided. Candidates are reminded that all quantitative answers should include appropriate units. The use of an approved scientific calculator is expected, where appropriate. Candidates are advised to show all their working in a clear and orderly manner, as more marks are awarded for sound use of Physics than for correct answers. The number of marks is given in brackets [ ] at the end of each question or part question. This document consists of 26 printed pages. [Turn over For Examiner's Use Section A /70 Q /10 TOTAL /80 Parent’s Signature:

2 Section A Answer all questions. 1 Two forces, 100 N and 50 N, act on an 8.0 kg box as shown in Fig. 1.1. The box is initially at rest. Fig. 1.1 (a) By using a suitable scale diagram, determine the magnitude of the resultant force acting on the box. resultant force = ........................................ [2] (b) Hence, determine the acceleration of the box. acceleration = ........................................ [1] (c) Calculate the speed of the box after 6.0 s. speed = ........................................ [1] [Total: 4] 50 N 100 N 75° 60°

3 2 (a) A cyclist applies a vertical force F of 110 N on a pedal of her bicycle, as shown in Fig. 2.1. Fig. 2.1 As she travels along, the pedal moves through a circle of radius 8.0 cm. For the pedal in the position shown in Fig. 2.1, the line of action of the force F is 5.0 cm from the pivot. (i) Calculate the moment of force F about the pivot. moment = …………………………… [2] (ii) The pedal moves from position A to position B, as shown in Fig. 2.1. Explain, in terms of moments, why the downward force F applied at A will have a different effect from the same force applied at B. ………………………………………………………………………………………. ………………………………………………………………………………………. …………………………………………………………………………………… [1] pedal chain pivot F = 110 N 5.0 cm A B

4 (b) A boy stands with his right foot and right shoulder touching a wall, and his centre of gravity as shown in Fig. 2.2. Fig. 2.2 Explain why the boy cannot raise his left foot off the ground without losing his balance. ………………………………………………………………………………………………. ………………………………………………………………………………………………. …………………………………………………………………………………………… [1] [Total: 4] 3 Fig. 3.1 shows part of the braking system of a car. Fig. 3.1 The brake pedal is connected to a piston A that can move in cylinder C filled with oil. The driver’s foot presses on the brake pedal, causing piston A to exert a force of 640 N on the oil in the cylinder. The cross-sectional area of piston A and cylinder C is 2.0 cm2. wall left foot centre of gravity foot force of foot brake pedal pivot cylinder C to all the wheels piston A cross-sectional area 2.0 cm2 oil

5 (a) Calculate the pressure in the oil due to the force exerted by piston A, giving your answer in the unit pascal. pressure = …………………………… Pa [2] (b) The cylinder at the brake pedal is connected by pipes containing oil to cylinders at each wheel. Fig. 3.2 shows cylinder D and piston B at one of the wheels. The cross- sectional area of piston B is 15 cm2. Fig. 3.2 Determine the force exerted by the oil on piston B. force = …………………………… [2] (c) A student suggests changing the size of cylinder D to a cross-sectional area of less than 2.0 cm2, so that it is less bulky and takes up less space. State and explain whether you agree with the student’s suggestion. ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. …………………………………………………………………………………………… [2] [Total: 6] 15 cm2 cylinder D to brakes at wheel piston B cross-sectional area oil from cylinder C

6 4 Fig. 4.1 shows a 1.2 kg ball rolling down a rough track from position A , which is 7.5 m above the ground, with an initial speed vo. The ball leaves the incline at position B, travels upward and reaches a maximum height of 10 m above the ground. The motion of the ball along the track produces a total of 25 J of thermal energy. The gravitational field strength is 10 N/kg. Fig. 4.1 (a) Calculate the gravitational potential energy of the ball at A. gravitational potential energy = …………………………… [2] (b) Determine the initial speed vo of the ball. vo = …………………………… [3] (c) State an assumption made in your answer to (b). ………………………………………………………………………………………………. …………………………………………………………………………………………… [1] [Total: 6] ground 10 m 7.5 m A B vo

7 5 Sonar waves emitted from a surface vessel are used to determine the depth of the sea. After a sonar wave is sent downward from the vessel , it takes 0.75 s for the signal reflected from the sea-bed to be detected. The speed of sound in water is 1200 m/s. (a) Calculate the depth of the sea. depth = …………………………… [2] (b) Explain how sound energy is transferred through the water. ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. …………………………………………………………………………………………… [2]

8 (c) The dots in Fig. 5. 1a represent the positions of equally spaced water particles before a sound wave passes through the water. The dots in Fig. 5. 1b represent the positions of the same water particles at one particular instant of time as the sound wave passes through. Fig. 5.2 (i) On Fig. 5.1b, mark out the wavelength of the sound wave and label it 𝜆. [1] (ii) On Fig. 5. 2, sketch the displacement -distance graph of the sound wave. Assume that positive displacement is to the right. [1] [Total: 6] Fig. 5.1a Fig. 5.1b displacement distance

9 6 A student performs an experiment to demonstrate the refraction of light in a rectangular glass block. Fig. 6.1 He repeats the experiment with the incident ray at different angles. The values obtained for the angle of incidence x and the angle of refraction y, as shown in Fig. 6.1, are given in Table 6.2. Table 6.2 x / ° 0 10 20 30 40 50 60 70 80 y / ° 0 7 13 20 26 31 36 39 42 (a) On Fig. 6.3, plot a graph of y against x. Draw the best fit curve through your points. Fig. 6.3 [2] x y 0 20 40 60 80 100 50 40 30 20 10 0 y / ° x / °

10 (b) Use your graph to estimate the critical angle for glass . Explain how you obtained your result. ………………………………………………………………………………………………. ………………………………………………………………………………………………. …………………………………………………………………………………………… [2] (