VJC 2025 J2 H2 Phy Prelim Paper 2

VJC 2025 9749/02/J2Prelim [Turn over VICTORIA JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME CLASS TUTOR NAME PHYSICS 9749/02 Paper 2 Structured Questions 16 September 2025 2 hours Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, class and tutor 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, 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. For Examiner’s Use 1 / 7 2 / 7 3 / 8 4 / 9 5 / 8 6 / 12 7 / 10 8 / 19 Total / 80 This document consists of 22 printed pages.

2 VJC 2025 9749/02/J2Prelim Data speed of light in free space c = 3.00 × 108 m s−1 permeability of free space  = 4 × 10−7 H m−1 permittivity of free space  = 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 VJC 2025 9749/02/J2Prelim [Turn over Formulae uniformly accelerated motion 21 2s ut at=+ 22 2v u as=+ work done on / by a gas W p V= hydrostatic pressure p gh= gravitational potential /Gm r =− temperature / K / C 273.15TT =  + pressure of an ideal gas 21 3 Nmpc V=   mean translational kinetic energy of an ideal molecule 3 2E kT= displacement of particle in s.h.m. 0 sinx x t = velocity of particle in s.h.m. 0 cosv v t = 22 0xx=  − electric current =I Anvq resistors in series 12 . . .R R R= + + resistors in parallel 121/ 1/ 1/ . . .R R R= + + electric potential 04 QV r= alternating current/voltage 0 sinx x t = magnetic flux density due to a long straight wire  = IB d 0 2 magnetic flux density due to a flat circular coil = NIB r 0 2 magnetic flux density due to a long solenoid =B nI 0 radioactive decay 0 exp( )x x t =− decay constant 1 2 ln2 t =

4 VJC 2025 9749/02/J2Prelim 1 A golfer is practising his tee shot from a platform 7.0 m off the ground as shown in Fig. 1.1. The golf ball was launched at a speed of 50 m s−1, 40 above the horizontal. Assume air resistance is negligible. (a) Determine the maximum height above the ground attained by the ball. maximum height = m [3] (b) Calculate the time of flight of the ball. time of flight = s [2] 50 m s−1 7.0 m ground Fig 1.1

5 VJC 2025 9749/02/J2Prelim [Turn over (c) A golf ball typically bounces a few times after a tee shot as shown in Fig. 1.2. The first time the ball touches the ground is indicated by A and the fourth time it touches the ground is indicated by B. Take the upward direction as positive. Fig. 1.2 Sketch, on Fig. 1.3, a graph to show the variation with time of the vertical velocity of the ball between from the instant it leaves A to the instant it reaches B. Fig. 1.3 [2] [Total: 7] A B vertical velocity time

6 VJC 2025 9749/02/J2Prelim 2 (a) Define Newton’s second law. [1] (b) A light rope is attached to a 120 kg box on the ground. The other end of the rope runs over a light frictionless pulley. A 80 kg man climbs up the free-hanging rope. As the man climbs up the rope, he pulls on the rope hard enough to cause himself to accelerate upwards. The only point of contact between the rope and the man occurs at his hands. Fig. 2.1 (i) Draw, on the outline of the man in Fig. 2.2, the forces acting on the man as he climbs. Fig. 2.1 [1]

7 VJC 2025 9749/02/J2Prelim [Turn over (ii) If the man climbs the rope with an acceleration of 8.0 m s −2, determine the acceleration of the box. acceleration = m s−2 [2] (c) The man releases the rope and the box falls. The box hits the ground with a speed of 2.0 m s −1 and sinks into the ground over a vertical distance of 10 cm before coming to a stop. Calculate the force exerted by the ground on the box during the deceleration. force = N [3] [Total: 7]

8 VJC 2025 9749/02/J2Prelim 3 A peg is fixed to the rim of a vertical turntable of radius r rotating with a constant angular speed , as shown in Fig. 3.1. Fig. 3.1 A parallel beam of light is incident on the turntable such that the shadow of the peg is observed on the screen. Initially, the peg is at position S  and its shadow is at S. After time t, the peg moves through an angle of  and it is positioned at T while its shadow is at T. The displacement x of the shadow from O is shown in Fig. 3.1 where the upward direction is taken to be positive. (a) (i) Express the angular displacement  of the peg in terms of  and t. [1] (ii) Write down an expression for the displacement x of the shadow on the screen in terms of , t and r . [1] (iii) Hence, prove that the shadow of the peg is moving in simple harmonic motion. Explain your working. [2]  r S S T T peg shadow of peg screen displacement x of shadow O

9 VJC 2025 9749/02/J2Prelim [Turn over (b) The turntable has a radius of 20.0 cm and angular speed of 3.5 rad s −1. For the motion of the shadow on the screen, (i) calculate the acceleration of the shadow when the shadow is instantaneously at rest, acceleration = m s−2 [1] (ii) determine the velocity of the shadow as it passes through O, velocity = m s−1 [1] (iii) sketch the variation with displacement x of the velocity v of the shadow. [2] [Total: 8] v / m s−1 x / m

10 VJC 2025 9749/02/J2Prelim 4 (a) Two waves are of the same frequency. Explain with the aid of a diagram what, for the two waves, is meant by phase difference. [2] (b) Monochromatic light is incident normally on a double slit as shown in Fig. 4.1. Light passes through the two slits B and C and is incident on the screen. Fig. 4.1 The centre of the interference pattern formed on the screen is at O. The separation between the fringes is y. r1 and r2 are two waves arriving at P. (i) 1. Deduce the relationship between the phase difference of the two waves arriving at point P and the distance x from point O. [1] 2. The waves have a phase difference of 12.6 radians when they meet at point P. Distance OP on the screen is 5.2 mm. Calculate the separation y between the fringes. y = m [2] monochromatic light O P r2 r2 r1 r1 B r2 C r2 x