Whitley Prelim P2

This document consists of 20 printed pages. Name: ( ) Class: WHITLEY SECONDARY SCHOOL A Caring and Learning Community of Leaders Perseverance * Respect * Integrity * Discipline *Empathy PRELIMINARY EXAMINATION 2024 READ THESE INSTRUCTIONS FIRST Write your index number and name on all the work you hand in. Write in dark blue or black ink on both sides of the paper. 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. Section B Answer all questions. Question 13 has a choice of parts to answer. 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. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. SUBJECT : Physics (6091) Paper 2 LEVEL : Sec 4 G3 DATE : 23 Aug 2024 DURATION : 1 hour 45 min SETTER : Mr Ng Mun Leong VETTER : Ms Kuah Li Wen

2 Section A Answer all the questions in this section. 1 A student measures the mass and the volume of four samples of rock P, Q, R and S. The results are shown in Fig. 1.1. P Q R S mass / g 202 101 4508 448 volume / cm3 44 22 978 80 Fig. 1.1 (a) (i) Describe in detail how a measuring cylinder is used to find the volume of rock Q. ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… ...…………………………………………………………………………… [2] (ii) Suggest why the volume of rock R cannot be found with an ordinary laboratory measuring cylinder. ………………………………………………………………………………… ...…………………………………………………………………………… [1] (b) Three of the rocks are made from the same material. State and explain which rock is made from a different material. …………………………………………………………………………………………. ……………………………………………………………………………………… [1]

3 2 Fig. 2.1 shows a man pushing a heavy box with a constant force X. A frictional force f acts in horizontal direction. Fig. 2.1 (a) The forces on the box are balanced and the box is stationary. (i) State what is meant by balanced forces. ………………………………………………………………………..…… [1] (ii) The frictional force in Fig. 2.1 does not produce any heating effect. State what must happen for the frictional force to produce heating. ………………………………………………………………………..…… [1] (iii) Apart from being stationary, describe one other possible state of motion of the box when the forces are balanced. ………………………………………………………………………..…… [1] (b) When X = 100 N and f = 85 N, the box accelerates. The mass of the box is 25 kg. Calculate the acceleration of the box. acceleration = ………………………. [2] (c) Explain, in terms of the forces acting, why the acceleration of the box is not constant. …………………………………………………………………………………………. …………………………………………………………………………………………. ……………………………………………………………………………………… [2] X f

4 (d) After 10 s, the man stops pushing and the velocity of the box starts to decrease. In the next 1.5 s, the box travels a distance of 5.0 m. At the end of this 1.5 s, the velocity of the box is zero. On Fig. 2.2, sketch the displacement-time graph of the box from 10s to 12s. Displacement is measured from the place the man stops pushing the box. Fig. 2.2 [2] 3 A worker carries a ladder on his shoulder. His shoulder acts as a pivot. Fig. 3.1 shows that the ladder is horizontal. Fig. 3.1 The ladder is wider at one end than at the other end. The mass of the ladder is 8.0kg. The gravitational field strength is 10 N / kg. (a) The centre of gravity of the ladder is not halfway along its length. State what this shows about the ladder. …………………………………………………………………………………………. ……………………………………………………………………………………… [1] centre of gravity

5 (b) The centre of gravity of the ladder is a horizontal distance of 0.90 m from the worker’s shoulder. Calculate the moment about the worker’s shoulder of the weight of the ladder. moment = …………………………. [2] (c) A bucket of weight 87 N is suspended from the ladder at a horizontal distance of 1.3 m from the worker’s shoulder. The worker keeps the ladder horizontal by exerting a vertical force at point L. Point L is at a horizontal distance of 0.54 m from his shoulder. Determine the size and direction of the force exerted at point L. size of force = ……………………. [2] direction of force = ……………………. [1] 4 Fig. 4.1 shows a trolley of mass 400 g moving at a constant velocity of 2.5 m s-1 to the right. Fig. 4.1 (a) Calculate the kinetic energy of the trolley. kinetic energy = ……………………. [2]

6 (b) The trolley moves to a point P as shown in Fig. 4.2. Fig. 4.2 At point P the speed of the trolley is 2.5 m s-1. A variable force F acts to the left of the trolley as it moves between points P and Q. The variation of F with the displacement x from P is shown in Fig. 4.3. Fig. 4.3 The trolley comes to rest at point Q. (i) Calculate the distance PQ. distance = ………………… [2]

7 (ii) On Fig. 4.4, sketch the variation of the velocity v with the displacement x for the trolley between P and Q. Fig. 4.4 [1] 5 (a) Fig. 5.1 shows food being cooked in an electric grill. Fig. 5.1 There are red-hot heating elements above the food and thermal energy (heat) is transmitted to the food by radiation. (i) Explain what is meant, in this case, by radiation. …………………………………………………………………………………. …………………………………………………………………………………. …...………………………………………………………………………… [2]

8 (ii) Explain why very little thermal energy is transmitted to the food by 1. conduction, ..…………………………………………………..…………………………… ....……………………………………………………………..…………… [1] 2. convection. ..…………………………………………………..…………………………… ....……………………………………………………………..…………… [1] (b) A laboratory experiment determination of the specific latent heat of vaporisation of water uses 120 W of heater to keep water boiling at its boiling point. Water is turned into steam at the rate of 0.050 g / s. (i) Calculate the specific latent heat of vaporisation of water that would be obtained from this experiment. specific latent heat = ………………….. [2] (ii) Explain why the energy calculated in (b)(i) is needed to boil the water and why the temperature of the water does not change during this stage. ……………………………………………..………………………………….. ……………………………………………..………………………………….. ……………………………………………..………………………………….. ……………………………………………..………………………………….. ….………………………………………………..………………………… [2]

9 6 (a) Fig. 6.1 shows the position of layers of air, at one moment, as sound wave of constant frequency passes through air. Compressions are labelled C and rarefactions are labelled R. Fig. 6.1 With reference to the compressions and rarefactions, state how Fig. 6.1 would change if (i) the sound had a higher frequency, …..……………………………………..……………………………………… ..…..……………………………………..………………………………… [1] (ii) the sound were louder. …..……………………………………………..……………………………… …..……………………………………………..……………………………… ..…..……………………………………………………………..………… [2] (b) A scientist in a laboratory made the following measurements during a thunderstorm. time from start of storm / min