NJC_2024_H2_Physics_Prelim_P3_QP

[Turn over NATIONAL JUNIOR COLLEGE SENIOR HIGH 2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME SUBJECT CLASS REGISTRATION NUMBER PHYSICS Paper 3 Structured Questions Candidate answers on the Question Paper. 9749/03 13 Sep 2024 2 hours No Additional Materials are required. READ THE INSTRUCTION FIRST Write your subject class, registration number and name in the spaces at the top of this page. Write in dark blue or black pen on both sides of the paper. You may use a HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. The use of an approved scientific calculator is expected, where appropriate. Section A Answers all questions. Section B Answer one question only. You are advised to spend one and a half hours on Section A and half an hour on Section B The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use Section A 1 / 9 2 / 7 3 / 10 4 / 13 5 / 8 6 / 6 7 / 7 Section B 8 / 20 9 / 20 H

2 Total (80) This document contains 29 printed pages and 3 blank pages.

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4 Section A Answer all the questions in the spaces provided. 1 (a) Use Newton's laws of motion to explain why a body moving with uniform speed in a circle must experience a force towards the centre of the circle. …………………………………………………………………………………………………………. …………………………………………………………………………………………………………. …………………………………………………………………………………………………………. …………………………………………………………………………………………………………. …………………………………………………………………………………………………………. ……………………………………………………………………………………………………… [3] (b) Fig. 1.1 shows the construction of a simple accelerometer that is used to measure the centripetal acceleration of a car turning into a corner. Fig. 1.1 (not to scale) The two ends A and B of the accelerometer are fixed to the car. A mass M is connected to two identical springs and it moves between A and B with negligible friction. A pointer attached to M indicates the acceleration of the car.

5 [Turn over The car enters the corner at a speed of 25 km h–1. The radius of the path of the car is 7.0 m. (i) Determine the centripetal acceleration of the car. centripetal acceleration = ……………………….…………… m s–2 [2] (ii) The mass M between the springs in the accelerometer is 0.50 kg. A test shows that a force of 1.0 N moves the pointer by 5.0 mm from its equilibrium position. Determine the displacement of the pointer from the equilibrium position when the car is turning into the corner. displacement = ……………………….…………….. mm [2] (iii) End B is nearer to the centre of the bend compared to A. Explain, in terms of forces exerted by the springs, whether the pointer of the accelerometer moves towards end A or B. …………………………………………………………………………………………....….. ………………………………………………………………………