PLMGSS Prelim 2024 4E Physics P2 QP + Ans

1 CANDIDATE NAME CLASS CLASS INDEX NUMBER CENTRE NUMBER INDEX NUMBER PHYSICS 6091/02 Paper 2 Structured and Free Response 20 August 2024 1 hour 45 minutes Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your class, index number and name on all the work you hand in. Write in dark blue or black pen. You may use an 2B 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 their working in a clear and orderly manner, as more marks are awarded for the 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. This document consists of 27 printed pages. For Examiner’s Use Section A / 70 Section B Qn _____ / 10 Total / 80 Paya Lebar Methodist Girls’ School (Secondary) Preliminary Examination 2024 Secondary 4 Express / G3

2 Section A (70 marks) Answer all questions. 1 Fig. 1.1 shows a satellite moving at a constant speed in a circular orbit around the Earth. Fig. 1.1 Speed is a scalar quantity but velocity is a vector quantity. (a) State how a scalar quantity differs from a vector quantity. ……………………………………………………………………………………. ………………………………………………………………………….……... [1] (b) Underline every vector quantity in the list below. distance displacement force length mass time [1] (c) There is a resultant force acting on the satellite in Fig. 1.1. This force acts in the radial direction toward the centre of the Earth. Explain if there is work done by the resultant force on the satellite after it travels one complete revolution. …………………………………………………………………………………… …………………………………………………………………………………… ………………………………………………………………………..…..…… [1]

3 [Turn Over 2 Fig. 2.1 is the distance–time graph for a stone that is dropped from rest at t = 0 at the surface of a lake. It starts to sink thereafter and eventually reaches terminal velocity. Fig. 2.1 (a) Using Fig. 2.1 and appropriate working, determine the terminal velocity of the stone. terminal velocity = ……………….. [2] (b) Describe how the resistive force due to water changes as the stone descends between t = 3 and t = 5 s. ………………………………………………………………………………… ……………………………………….…………………………………..… [1] (c) Acceleration of the stone decreases between t = 3 and t = 5 s. By considering the forces acting on the stone, explain why. ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… ………………………………………………………………………………… …………………………………………………….………..…………….... [2] distance / mm

4 3 A 1.5 kg stone, released at A, falls vertically, hits a rubber mat at B and rebounds vertically upwards from C onwards. Fig. 3.1 shows the velocity-time graph of the stone. Fig. 3.1 (a) By calculating the energy in the kinetic store and using ideas about conservation of energy, determine the height through which the stone at A has fallen before it hits the rubber mat at B. Take gravitational field strength g to be 10 N / kg. height = ……………………… [2] (b) Using Fig. 3.1 and with appropriate calculation, verify if the stone is under free fall during AB. …………...………………………..…………………………………..…… [1]

5 [Turn Over (c) Using Fig. 3.1, estimate the maximum height attained by the stone after the rebound. maximum height = …………………… [1] (d) The magnitude of the stone’s acceleration during BC is 180 m / s2. Calculate the normal contact force acting on the stone during BC. normal contact force = …………………….. [2]

6 4 Fig. 4.1 shows a door and an automatic door-closer viewed from above. Fig. 4.1 When the door opens and closes, the hinge acts as a pivot. A girl opens the door by exerting a force P at point X. Force P is perpendicular to the surface of the door. (a) Fig. 4.1 shows that point X is a distance of 0.72 m along the front of the door from the hinge. The force P is 25 N. (i) Calculate the moment of force P about the hinge. moment = ……………………. [1] (ii) The door rotates about the hinge by 90°. The circumference of a circle of radius 0.72 m is 4.5 m. Calculate the work done on the door by force P. work done = ………………. [2] 0.50 m

7 [Turn Over (b) As the door opens, there is a force F on the door in the direction shown in Fig. 4.1. Although force F is larger than the applied force P, the girl is still able to cause the door to rotate about the hinge. Explain why. ………………………………………………………………………………………. ………………………………………………………………………………………. ………………………………………………………………………………………. ……………………………...…………………………………………………… [1]

8 5 Object A of mass 500 g moved down a slide from a vertical height of 3.0 m as shown in Fig. 5.1. Object A was released with an initial speed of 5.0 m/s and its speed at the lowest point L was 8.0 m/s. Fig. 5.1 (a) State what is meant by work done. ……………………………………………………………………………….......... ………………………………………………………….………………….…........ …………………………………………………………………………….……..... …………………………………………………………………..……..…......... [2] (b) Calculate the amount of energy transferred into object A’s kinetic store when object A reaches point L. energy transfer = …………………. [2] (c) Determine the amount of energy transferred into the internal store when object A reaches point . energy transfer = ………………….. [2] L L

9 [Turn Over 6 Fig. 6.1 shows a mercury barometer. The density of mercury is 14000 kg / m3. Fig. 6.1 (a) Using ideas of random motion of air particles, explain how the atmosphere exerts a pressure on the surface of the mercury at A. ……………………………………………………………………………………. ……………………………………………………………………………………. …………………………………………………………………………………. [1] (b) Determine the atmospheric pressure in Pa. atmospheric pressure = ……………………… Pa [2] (c) In Fig. 6.1, mark with ‘X on the metre rule where the pressure is 5 cm Hg lower than the atmospheric pressure. [1] metre rule reservoir mercury

10 7 Fig. 7.1 shows the inner vessel of a double walled steel mug containing ice cold water. The double walls of the mug are sealed such that there is a vacuum between them. Fig. 7.1 (a) Explain how the design of the mug reduces heat gained by the ice cold water. ……………………………………………………………………………………….. ……………..………………………………………………………………………… ……………………………………………………………………………………….. ……………………………………………………………………………………. [2] (b) A student pours hot coffee at 95 °C into the steel mug. The heat capacity of the coffee is 630 J / °C. Ignore the heat capacity of the steel mug. (i) Explain how the design is less effective when the mug is used to keep hot beverages hot and how the design can be improved. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………....... [2] (ii) The hot coffee loses thermal energy to the surroundings at a constant rate of 60 J / s and the optimum temperature of drinking the coffee is 80 °C. How long does it take before the student can drink it? time taken = …………....... [2] silvered surface vacuum ice cold water