YTSS 2025 P2 Prelims

NAME: ( ) CLASS: YISHUN TOWN SECONDARY SCHOOL PRELIMINARY EXAMINATION 2025 SECONDARY 4 G3 PHYSICS (6091/2) DATE : 19 Aug 2025 DAY : Tuesday DURATION: 1 hr 45 min MARKS: 80 marks READ THESE INSTRUCTIONS FIRST Write your name, class and register number in the spaces provided at the top of this page. Section A Answer all the questions. Write your answers in the spaces provided. Section B Answer one question. Write your answers in the spaces provided. INFORMATION FOR CANDIDATES The number of marks is given in brackets [ ] at the end of each question or part question. Candidates are reminded that all quantitative answers should include appropriate units. You may use an approved calculator. Section A /70 Section B /10 TOTAL /80 This question paper consists of 21 printed pages.

2 Section A Answer all questions. 1 Fig. 1.1 shows one method of measuring the diameter of a beaker. Fig 1.1 (a) State the diameter of the beaker. ………………………………………………………………………………………….... [1] (b) Suggest an instrument that could measure the diameter of the beaker more precisely. ……………………………………………………………………………………….…... [1] (c) Student A makes use of the readings taken in (a) to calculate the base area of the beaker. Student B makes use of the instrument in (b) and tells student A that his calculated area is more accurate. State if you agree with student B and explain your answer. ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………….... [2] ruler . wooden block . beaker . bench .

3 2 Fig. 2.1 shows a ball being released from rest from its initial position above the ground. The ball falls vertically and rebounds. initial position ball rebound Fig 2.2 shows how the velocity of the ball varies with time. Fig. 2.2 Fig. 2.1 ground

4 (a) Using the information from the graph, calculate: (i) the acceleration of the ball after it rebounds. acceleration = [2] (ii) the initial height the ball was released. height = [2] (iii) the displacement from the initial position after the ball has reached its maximum height after the first rebound. displacement = [2] (b) Explain how Fig. 2.2 shows that the effect of air resistance on the ball is negligible. ………………………………………………………………………………………………. …………………………………………………………………………………………...... [1]

5 3 Fig. 3.1 shows a wheelbarrow and its load, which has a total mass of 15 kg . This is supported by a vertical force F at the end of its handles. The centre of gravity of the wheelbarrow is marked, c.g. on Fig. 3.1. Fig. 3.1 (a) (i) State the Principle of Moments. ………………………………………………………………………………….....……. ………………………………………………………………………………….....……. ………………………………………………………………………………….....……. …………………………………………………….………………………………….[2] (ii) Hence, determine the vertical force, F, to keep the wheelbarrow in equilibrium. F = [2] (b) The force, F in (a)(ii) is found to have a different value from 150 N. A student says that the wheelbarrow cannot be in equilibrium since the upward forces are not equal to the downward forces. Explain why the student is incorrect. You may draw on Fig. 3.1 to further substantiate your answer to show how the wheelbarrow is in equilibrium. ………………………………………………………………………………………………. ………………………………………………………………………………………………. …………………………………………………………………………………..……….... [2] c.g . .

6 4 Fig. 4.1 shows a manometer attached to a gas cylinder. Fig. 4.1 (a) (i) The density of water is 1000 kg/m3 and the gravitational field strength is 10 N/kg. Calculate the pressure difference in Pa as shown by the manometer. pressure difference = Pa [2] (ii) The water is replaced with an equal volume of oil with a density of 900 kg/m 3. Determine the liquid level of the left and right arm of the manometer. liquid level on right arm = ………………………………. liquid level on left arm = ……………………………[2] gas cylinder . water .

7 (b) An engineer decides to evacuate the air and seal the open end of the manometer in Fig. 4.1. State if the manometer can still be used to measure the gas pressure. Explain your answer. ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………[2] 5 Fig. 5.1 shows a transverse wave travelling along a rope. The positions of the wave at the time intervals t = 0 s and t = 2.0 s are shown. Fig. 5.1 (a) Explain what is meant by a transverse wave. ……………………………………………………………………………………………….... …………………………………………………………………………………………….. [1] (b) Calculate the speed of the wave. speed = [1]

8 (c) Determine the period of the wave. period = [2] (d) X is a particle on the wave at t = 0 s. On Fig. 5.1, mark the new position of X at t = 6.0 s. Label this position Y. [1] 6 The device shown in Fig. 6.1 uses the reflection of ultrasound to measure distances. Fig. 6.1 (a) State what is meant by ultrasound. ………………………………………………………………………………………………. ………………………………………………………………………………………….... [2] ultrasound wave .

9 (b) Fig. 6.2 shows a contractor using the device to measure the width of a room. Fig. 6.2 The ultrasound device is placed against one side of the wall and it emits an ultrasound wave that reflects back from the opposite side of the wall. The time between sending out the ultrasound wave and receiving the reflection is 30 ms . The speed of ultrasound in air is 340 m/s. Calculate the distance between the device and the opposite wall. distance = [2] 7 When light passes from one optical medium to another, one physical quantity changes while the other remains constant. (a) State the physical quantity that changes and the one that remains constant. [1] changes: ……………………………………….. remains constant: ……………………………... ultrasound wave .

10 (b) Fig. 7.1 shows the path of a light ray in a glass prism, ABC. The refractive index of the glass prism is 1.80. Fig. 7.1 Calculate the angle in which the light ray deviates from its original path on surface AB. angle of deviation = ……………………………. [3] (c) On Fig. 7.2, draw a ray diagram to show how a converging lens is used in a photocopier producing identical copies of the same document. [2] Fig. 7.2 A B C 32º Lens .