CHS 2021 - Sec 4 PHYSICS Prelim Exam PAPER 2 - Questions

1 Name: Index Number: Class: CATHOLIC HIGH SCHOOL Preliminary Examination Secondary 4 (O-Level Programme) PHYSICS 6091/02 Paper 2 Theory 15 September 2021 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 that you hand in. Write in dark blue or black pen. You may use an 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. 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 workings 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. For examiner’s use only: Section A / 50 Section B / 30 Total Marks / 80 Paper Type of Paper Marks Weighting 1 Multiple Choice 40 30 % 2 Theory 80 50 % 3 Practical 40 20 % This document consists of 20 printed pages. 50  s.f.  formula Section A

2 Section A Answer all the questions in this section. 1 A rock from space is travelling in a straight line at high speed when it enters the Earth’s atmosphere. Fig. 1.1 is the speed-time graph for the rock from time t = 0 to time t = 50 s. Fig. 1.1 (a) (i) On Fig. 1.1, mark with 1. a letter X, where the rock is moving with a constant speed, 2. a letter Y, where the rock has a non-uniform deceleration. [2] (ii) At time t = 25 s, the mass of the rock is 8.4 kg. Determine, at this instant, 1. the magnitude of the acceleration of the rock, acceleration = [2]

3 2. the magnitude of the resultant force on the rock. force = [1] (b) (i) Fig. 1.2 shows the rock at time t = 25 s. Fig. 1.2 1. On Fig. 1.2, draw and label an arrow to show the direction of the gravitational force F acting on the rock. [1] 2. Explain why the direction of travel of the rock changes as it travels through the Earth’s atmosphere. [2] (ii) State what happens to the rock at time t = 40 s. [1]

4 2 Fig. 2.1 shows a screwdriver of mass 64 g resting in equilibrium on a pivot. Fig. 2.1 (a) (i) Calculate the magnitude of the normal contact force from the pivot acting on the screwdriver. force = [1] (ii) A student suggested that the weight of the screwdriver and the normal contact force of the pivot acting on the screwdriver form an action-reaction pair. Explain why the student is wrong. [1] (b) (i) On Fig. 2.1, mark and label with a letter C, the centre of gravi