ASRJC 2022 Prelim P3

1 9749/03/ASRJC/2022PRELIM [Turn Over Name: _____________________________ ( ) Class: 22 / ______ 2022 JC2 Preliminary Examination PHYSICS Higher 2 9749/03 Paper 3 Longer Structured Questions Thursday 15 September 2022 2 hours Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, class index number and class in the spaces provided above. Write in dark blue or black pen on both sides of the paper. You may use an HB pencil for any diagrams or graphs. The use of an approved scientific calculator is expected, where appropriate. Section A Answer all questions. Section B Answer one question only. You are advised to spend about one and a half hours on Section A and half an hour on Section B. 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 25 printed pages and 3 blank pages. For Examiner’s Use Paper 3 (80 marks) 1 / 8 2 / 9 3 / 12 4 / 11 5 / 11 6 / 9 7 / 20 8 / 20 Deduct Total ANDERSON SERANGOON JUNIOR COLLEGE

2 9749/03/ASRC/2022PRELIM Data speed of light in free space c = 3.00 x 108 m s-1 permeability of free space 0 = 4 x 10-7 H m-1 permittivity of free space 0 = 8.85 x 10-12 F m-1 (1/(36)) x 10-9 F m-1 elementary charge e = 1.60 x 10-19 C the Planck constant h = 6.63 x 10-34 J s unified atomic mass constant u = 1.66 x 10-27 kg rest mass of electron me = 9.11 x 10-31 kg rest mass of proton mp = 1.67 x 10-27 kg molar gas constant R = 8.31 J K-1 mol-1 the Avogadro constant NA = 6.02 x 1023 mol-1 the Boltzmann constant k = 1.38 x 10-23 J K-1 gravitational constant G = 6.67 x 10-11 N m2 kg-2 acceleration of free fall g = 9.81 m s-2

3 9749/03/ASRJC/2022PRELIM [Turn Over Formulae uniformly accelerated motion =s 2 2 1 atut + =2v asu 22 + work done on/by a gas =W Vp hydrostatic pressure =p gh gravitational potential = r Gm− temperature T/K = T/C + 273.15 pressure of an ideal gas p =  2 3 1 cV Nm mean translational kinetic energy of an ideal gas molecule =E kT2 3 displacement of particle in s.h.m. x = x0 sin  t velocity of particle in s.h.m. v = v0 cos  t = 22 xxo − electric current I = Anvq resistors in series R = R1 + R2 + … resistors in parallel 1/R = 1/R1 + 1/R2 + … electric potential V = r Q o4 alternating current/voltage x = x0 sin  t magnetic flux density due to a long straight wire B = d o   2 I magnetic flux density due to a flat circular coil B = r No 2 I magnetic flux density due to a long solenoid B = Ino radioactive decay x = x0 exp(–t) decay constant  = 2 1 2ln t

4 9749/03/ASRC/2022PRELIM Section A Answer all the questions in this Section in the spaces provided. 1 (a) State Newton’s second law of motion. …………………………………………………………………………………………….……….. ………………………………………………………………………………………….………….. …………………………………………………………………………………………….......... [2] (b) Two objects X and Y are attached together by a rope of negligible mass over a frictionless pulley in Fig. 1.1. Fig. 1.1 The mass of object X is greater than the mass of object Y. Object Y is held on the ground and object X is at a vertical height of 5.0 m above the ground. Object Y is released. Air resistance is negligible. (i) Explain why the acceleration of object X is less than the acceleration of free fall g. ………………………………………………………………………………….................... ………………………………………………………………………………….................... ……………………………………………………………………………….………….... [1] 5.0 m X Y ground frictionless pulley

5 9749/03/ASRJC/2022PRELIM [Turn Over (ii) Show that the acceleration of object Y is given by the relation XY XY mmag mm −= + where mX is the mass of object X, mY is the mass of object Y, and g is the acceleration of free fall. [3] (iii) The mass of object X is 6.0 kg and the mass of object Y is 3.0 kg. Calculate the time taken by object X to reach the ground. time taken = ……………………………. s [2] [Total: 8]

6 9749/03/ASRC/2022PRELIM 2 A mass is suspended from one end of a spring as shown in Fig. 2.1a. The mass is lowered into a beaker of water until it is fully submerged as shown in Fig. 2.1b. The extension of the spring reduces by 4.5 mm when the mass is fully submerged. Fig. 2.1a Fig. 2.1b The spring has a spring constant of 42 N m−1 and the density of water is 1000 kg m−3. (a) Show that the upthrust acting on the mass is 0.19 N. [2] (b) Determine the volume of the mass. volume = …………… m3 [2] (c) State the magnitude of force that the mass exerts on the water and explain your answer. …………………………………………………………………………………………….……….. …………………………………………………………………………………………….……….. …………………………………………………………………………………………….......... [2] water

7 9749/03/ASRJC/2022PRELIM [Turn Over (d) The mass is slowly raised vertically by lifting the upper end of the spring. The vertical distance moved by the mass from its original position is s. The mass reaches constant speed at s = s1 as shown in Fig. 2.2a. It continues to move at a constant speed until it is fully out of the water for a short distance at s = s2 as shown in Fig. 2.2b. On the axes of Fig. 2.3 below, sketch the variation with s of the extension e of the spring, from s1 to s2. Drag force is negligible. Fig. 2.3 [3] [Total: 9] s1 s2 water e s 0 s1 s2 Fig. 2.2a Fig. 2.2b

8 9749/03/ASRC/2022PRELIM 3 (a) (i) Define gravitational potential at a point. ………………………………………………………………………………….................... ………………………………………………………………………………….................... ……………………………………………………………………………….………….... [2] (ii) Explain why gravitational potential is negative. ………………………………………………………………………………….................... ………………………………………………………………………………….................... ………………………………………………………………………………….................... ………………………………………………………………………………….................... ………………………………………………………………………………….................... ………………………………………………………………………………….................... ………………………………………………………………………………….................... ……………………………………………………………………………….………….... [3] (b) A moon of mass M and radius R orbits a planet of mass 3M and radius 2R. At a particular time, the distance between their centres is D, as shown in Fig. 3.1. Fig. 3.1 Point P is a point along the line between the centres of the planet and the moon, at a variable distance x from the centre of the planet. The variation with x of the gravitational potential ϕ at point P, for points between the planet and the moon, is shown in Fig. 3.2. D x P planet mass 3M radius 2R moon mass M radius R

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