2023 CHS Phy Prelims P2

Name: Index Number: Class: CATHOLIC HIGH SCHOOL Preliminary Examination Secondary 4 (O-Level Programme) PHYSICS 6091/02 Paper 2 Theory 25 Aug 2023 1 hour 45 minutes Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, index number and class on all the work you hand in. Write in dark blue or black link. You may use a HB pencil for any diagrams or graphs. Do not use paper clips, glue or correction fluid. Section A Answer all questions. Section B Answer all questions. Question 12 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. The number of marks is given in brackets [ ] at the end of each question or part question. For examiner’s use only: Section A / 50 Section B / 30 Total / 80 Overall Marks % Paper 1 40 30% Paper 2A 50 50% Paper 2B 30 Paper 3 40 20% This document consists of 26 printed pages. 50  s.f.  formula Paper 2A

2 Section A Answer all the questions in this section. 1 A rock of mass 7.5 kg is projected vertically upwards from the surface of planet X. The rock leaves the surface of planet X with a velocity of 4.0 m / s at time t = 0 s. The variation of velocity v with time t of the rock is shown in Fig. 1.1. Fig. 1.1 Assume that the air resistance acting on the rock is zero. (a) (i) Determine the height of the rock above the surface of planet X at time t = 2.5 s. height = [2] (ii) Determine the deceleration of the rock. deceleration = [2]

3 (b) The rock is now thrown vertically upwards on another planet Y with an initial velocity of 4.0 m / s. Planet Y has the same gravitational field strength as planet X. Air resistance acting on the rock is not negligible. (i) The resultant force acting on the rock is downwards and decreasing as it travels upwards. On Fig. 1.1 , draw the velocity-time graph of the rock on planet Y until it reaches the highest point. [1] (ii) Determine the magnitude of air resistance when the rock is travelling at terminal velocity at planet Y. air resistance = [1]

4 2 Fig. 2.1 shows a rocket about to be launched. Fig. 2.1 The total mass of the rocket and its full load of fuel is 2.8 × 106 kg. The motor of the rocket provides a constant force. The vertical acceleration of the rocket immediately after lift-off is 1.4 m / s2. The gravitational field strength of Earth is 10 N / kg. (a) Calculate the constant force provided by the motor of the rocket.