ASRJC Prelim H2P2 (9749) Final

1 9749/02/ASRJC/2023Prelim [Turn over Name: _____________________________ ( ) Class: 23 / ______ 2023 JC2 Preliminary Examination PHYSICS Higher 2 9749/02 Paper 2 Structured Questions Wednesday 13 September 2023 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 at the top of this page. Write in dark blue or black pen on both sides of the paper. You may use an 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. Answer all questions. The number of marks is given in brackets [ ] at the end of each question or part question. This document consists of 26 printed pages and 2 blank pages. For Examiner’s Use Paper 2 (80 marks) 1 2 3 4 5 6 7 8 Deductions Total ANDERSON SERANGOON JUNIOR COLLEGE

2 9749/02/ASRJC/2023Prelim Data speed of light in free space c = 3.00  108 m s−1 permeability of free space o = 4  10−7 H m−1 permittivity of free space o = 8.85  10−12 F m−1 (1/(36))  10−9 F m−1 elementary charge e = 1.60  10−19 C the Planck constant h = 6.63  10−34 J s unified atomic mass constant u = 1.66  10−27 kg rest mass of electron me = 9.11  10−31 kg rest mass of proton mp = 1.67  10−27 kg molar gas constant R = 8.31 J K−1 mol−1 the Avogadro constant NA = 6.02  1023 mol−1 the Boltzmann constant k = 1.38  10−23 J K−1 gravitational constant G = 6.67  10−11 N m2 kg−2 acceleration of free fall g = 9.81 m s−2

3 9749/02/ASRJC/2023Prelim [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 9749/02/ASRJC/2023Prelim Answer all the questions in the spaces provided. 1 A spring has an unstretched length of 6.0 cm. The top of the spring is attached to a fixed point. A brass block of mass 180 g and volume 2.0 × 10–5 m3 is suspended from the lower end so that the length of the spring increases to 9.6 cm, shown in Fig. 1.1. Fig. 1.1 Fig 1.1 is not drawn to scale. (a) Calculate the force constant of the spring. force constant = ……………………… N m–1 [2] (b) The percentage uncertainty in the mass is ± 2.0%. The actual uncertainty in each measurement of the length of the spring is ± 1 mm. Calculate the actual uncertainty in the force constant. actual uncertainty = ……………………… N m–1 [2] brass block mass 180 g

5 9749/02/ASRJC/2023Prelim [Turn Over (c) The block is submerged in a liquid of density . The length of the spring is now 9.0 cm, as shown in Fig. 1.2. Fig. 1.2 (i) Using the definitions of pressure and density, show that the hydrostatic pressure p at a depth h below the surface of the liquid is given by p =  gh where g is the acceleration of free fall. [2] (ii) Hence, or otherwise, determine .  = ……………………… kg m–3 [3] [Total: 9] 9.0 cm liquid surface

6 9749/02/ASRJC/2023Prelim 2 Two blocks travel directly towards each other along a horizontal, frictionless surface, as illustrated in Fig. 2.1. Fig. 2.1 Block A has a mass 3M and is moving towards block B with a speed of 0.40 m s-1. Block B has a mass M and is moving towards block A with a speed of 0.25 m s-1. (a) Explain whether, during the collision, it is possible for both blocks to be at rest simultaneously. ………………………………………………………………………………………….………….. ………………………………………………………………………………………….………….. …………………………………………………………………………………………….......... [2] (b) (i) After the blocks collide, block A continues its direction of motion and moves off with a speed of 0.20 m s-1. Calculate the speed of block B after the collision. speed = …………………………….m s-1 [1] (ii) Use your answer in (b)(i), state and explain the direction of motion of block B. ………………………………………………………………………………….................... ……………………………………………………………………………….………….... [1] (c) A light plasticine is placed on block A so that the two blocks stick together after collision. State and explain whether the collision is elastic or inelastic. ………………………………………………………………………………………….………….. ………………………………………………………………………………………….………….. …………………………………………………………………………………………….......... [2] [Total: 6] speed before collision

7 9749/02/ASRJC/2023Prelim [Turn Over Question 3 starts on the next page.

8 9749/02/ASRJC/2023Prelim 3 (a) (i) Define gravitational potential at a point. ………………………………………………………………………………….................... ………………………………………………………………………………….................... ……………………………………………………………………………….………….... [1] (ii) Suggest why, for small changes in height near the Earth’s surface, gravitational potential is approximately constant. ………………………………………………………………………………….................... ………………………………………………………………………………….................... ………………………………………………………………………………….................... ……………………………………………………………………………….………….... [2] (b) An isolated solid sphere of radius r may be assumed to have its mass M concentrated at its centre. The magnitude of the gravitational potential at the surface of the sphere is . On Fig. 3.1, show the variation of the gravitational potential with distance d from the centre of the sphere for values of d from d = r to d = 4r. Fig. 3.1 [2]

9 9749/02/ASRJC/2023Prelim [Turn Over (c) The sphere in (b) is a planet with radius r of 6.4 × 106 m and mass M of 6.0 × 1024 kg. The planet has no atmosphere. A rock, initially at rest a long distance from the planet, travels towards its surface. Calculate the change in speed of the rock as it s distance from the centre of the planet changes from 4r to 3r. change in speed = ....................................................... m s-1 [3] [Total: 8]

10 9749/02/ASRJC/2023Prelim 4 Fig. 4.1 shows the variation with time t of the height h above the ground of an object of mass 36 kg that is undergoing vertical simple harmonic motion. Fig. 4.1 (a) State the defining equation for simple harmonic motion. Identify the meaning of each of the symbols used to represent physical quantities. …………………………………………………………………………………………….……….. ………………………………………………………………………………………….………….. …………………………………………………………………………………………….......... [1] (b)