NJC 2024 H2 Physics Prelim P2 QP

[Turn over NATIONAL JUNIOR COLLEGE SENIOR HIGH 2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME SUBJECT CLASS REGISTRATION NUMBER PHYSICS Paper 2 Structured Questions Candidate answers on the Question Paper. 9749/02 27 August 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. Answers all questions. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use 1 / 8 2 / 9 3 / 4 4 / 6 5 / 11 6 / 10 7 / 10 8 / 22 Total (80) H

2 This document contains 28 printed pages and 3 blank pages.

3 [Turn over

4 Answer all the questions in the spaces provided. 1 An object is launched at a speed of 30 m s–1 with an angle of 60° from the ground as shown in Fig. 1.1. Ignore air resistance. 60o 30 m s-1 Fig 1.1 (a) Show that the time taken for the object to reach its maximum height is 2.6 s. [1] (b) Sketch the variation with time t of the vertical component of the velocity vy on Fig. 1.2, from the time it leaves the ground to the time it returns to the ground. [2] vy / m s-1 t/s 0 10 20 -20 -10 -30 30 1.0 2.0 3.0 4.0 5.0 6.0

5 [Turn over (c) Sketch on Fig. 1.3, (i) the variation of the horizontal component of the velocity vx with time of the object for the duration of time in flight. Label this line A. [1] (ii) the variation of the horizontal component of the velocity vx with time of the object for the duration of time in flight if air resistance is not negligible. Label this line B. [2] (d) A second object is launched at the same instant with the same speed but at an angle of 30o above the ground. Air resistance is negligible. Determine the vertical displacement between the two objects at 2.6 s. Fig. 1.2 vx / m s-1 t/s 0 10 20 30 1.0 2.0 3.0 4.0 5.0 Fig. 1.3

6 vertical displacement = ……………………………………. m [2] [Total: 8 marks]

7 [Turn over 2 (a) State the relation between force and momentum. …………………………………………………………………………………………………………. [1] (b) A rigid bar of mass 450 g is held horizontally by two supports A and B, as shown in Fig. 2.1 Fig. 2.1 The support A is 45 cm from the centre of gravity C of the bar and support B is 25 cm from C. A ball of mass 140 g falls vertically onto the bar such that it hits the bar at a distance of 50 cm from C, as shown in Fig. 2.1. The variation with time t of the velocity v of the ball before, during and after hitting the bar is shown in Fig. 2.2. Fig. 2.2

8 For the time that the ball is in contact with the bar, use Fig. 2.2 to (i) determine the resultant force acting on the ball, resultant force = ……………………………………. N [2] (ii) show that the force exerted by the ball on the bar is 35 N. [1] (c) For the time that the ball is in contact with the bar, use data from Fig. 2.1. and (b)(ii) to calculate the force exerted on the bar by (i) the support A, force = ……………………………………. N [3] (ii) the support B, force = ……………………………………. N [2]

9 [Turn over [Total: 9 marks] 3 (a) Fig 3.1 below shows a closed symmetrical jar with dimensions as shown. It contains a liquid of mass 3.0 kg and density 900 kg m-3. The liquid exerts a pressure on the base of the jar. Fig. 3.1 3.0 cm 3.0 cm Area of base 9.0 cm2 Determine the pressure exerted by the liquid at the base of the jar. pressure = ……………………………………. Pa [2]

10 (b) Fig 3.2 below shows an object that is not in equilibrium partially submerged in water. water Object not in equilibrium Fig 3.2 The density of the object is uniform and is less than the density of water. By drawing the weight of the object W and the upthrust U acting on the object on Fig. 3.2, describe briefly what will happen to the object and suggest its approximate position after it comes to equilibrium. …………………………………………………………………………………………………………………….. …………………………………………………………………………………………………………………….. ………………………………………………………………………………………………………………… [2] [Total: 4 marks]