TJC 2025 H2 Prelim Paper 3

TEMASEK JUNIOR COLLEGE 2025 JC2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME CENTRE NUMBER S INDEX NUMBER PHYSICS 9749/03 Paper 3 Longer Structured Questions 17 September 2025 2 hour Candidates answer on the Question Paper. For Examiner’s Use READ THESE INSTRUCTIONS FIRST 1 Write your name and civics group in the spaces at the top of this page. 2 Write in dark blue or black pen on both sides of the paper. 3 You may use an HB pencil for any diagrams or graphs. 4 Do not use staples, paper clips, glue or correction fluid. 5 The use of an approved scientific calculator is expected, where appropriate. 6 Section A Answer all questions. 7 8 Section B Answer one question only You are advised to spend one and a half hour on Section A and half an hour on Section B. s.f The number of marks is given in brackets [ ] at the end of each question or part question. Total This document consists of 24 printed pages

DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN 2 Data speed of light in free space c = 3.00 x 108 m s-1 permeability of free space o = 4 x 10-7 H m-1 permittivity of free space o = 8.85 x 10-12 F m-1 or (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 Js 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 Formulae uniformly accelerated motion s = ut + ½ at2 v2 = u2 + 2as work done on/by a gas W = p ΔV hydrostatic pressure p = gh gravitational potential  = –Gm/r temperature T/K = T/oC + 273.15 pressure of an ideal gas p = 3 1 V Nm < c2 > mean translational kinetic energy of an ideal gas molecule E = 2 3 kT displacement of particle in s.h.m. x = xosint velocity of particle in s.h.m. v = vocos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 = rε4π Q o alternating current/voltage x = xo sint magnetic flux density due to a long straight wire B = 𝜇𝑜𝐼 2𝜋𝑑 magnetic flux density due to a flat circular coil B = 𝜇𝑜𝑁𝐼 2𝑟 magnetic flux density due to a long solenoid B = onI radioactive decay x = x0 exp(−t) decay constant λ = 𝑙𝑛2 𝑡1/2

DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN 3 [Turn over Section A Answer all the questions in the spaces provided. 1 Using a handheld catapult, a student projected a stone of mass 130 g, horizontally from a building rooftop of height 32 m, as illustrated in Fig. 1.1, aiming for it to land in an adjacent river. Air resistance is negligible and the stone enters the water at a speed of 34 m s-1 after time tS. (a) Determine for the stone as it hits the water, (i) the vertical component of the velocity of the stone vertical component of velocity = m s–1 [2] (ii) the angle  to the horizontal of the stone’s plunge  = o [2] Fig. 1.1 path of stone building river 32 m 

DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN 4 (b) Use energy considerations to suggest why, if the stone causes a large splash on hitting the water surface, it decelerates in a shorter distance than when no splash is produced. [1] (c) (i) On Fig. 1.2, sketch the variation with time t of the potential energy Ep of the stone with respect to the water level. [2] (ii) On Fig. 1.3, sketch the variation with time t of the kinetic energy Ek of the stone for the same period. [1] [Total: 8] Ep t tS | Fig. 1.2 Ek t tS | Fig. 1.3

DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN 5 [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. Support A is 45 cm from the centre of mass C of the bar while 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 point D, a distance of 50 cm from C. Fig. 2.1 D

DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN 6 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. For the time that the ball is in contact with the bar, use the data provided to (i) determine the change in momentum of the ball, change in momemtum = kg m s-1 [2] Fig. 2.2

DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN 7 [Turn over (ii) show that the magnitude of the average force exerted by the ball on the bar is 35 N, [2] (iii) calculate the average force exerted on the bar by the support A. force = N [2] (iv) determine the net energy lost by the ball due to the inelastic collision with the bar at D. energy = J [1]

DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN 8 (c) The ball is now dropped under the same conditions, this time with a light cushion fitted at point D. Explain the effect on your answer to (b)(iii) when the ball makes contact at point D. [2] [Total: 10] 3 A cycle of changes in pressure, volume and temperature of gas inside a cylinder of a petrol engine with a movable piston is illustrated in Fig. 3.1. The gas is assumed to be ideal. Fig. 3.1 (not to scale) There are four stages in the cycle. stage description A to B Rapid compression of the gaseous petrol/air mixture with the temperature rising from 300 K at A and the pressure rising to 44 × 105 Pa at B. B to C The petrol/air mixture is exploded, resulting in an almost instant rise in pressure. At C the temperature has risen to 1960 K. C to D Rapid expansion and cooling of the hot gases. D to A Return to the starting point of the cycle.

DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN 9 [Turn over (a) (i) State what is meant by an ideal gas. [1] (ii) Use the values in Fig. 3.1 to determine the number of moles present in the gases in the cycle. number of moles = moles [2] (b) Complete the table in Fig. 3.2 showing the work done on the gas, the heat supplied to the gas and the increase in the internal energy of the gas, during the four stages of one cycle. stage work done on gas /J heat supplied to gas /J increase in internal energy of gas / J A to B + 360 0 B to C + 670 C to D 0 − 810 D to A [4] (c) Explain qualitatively how molecular movement causes the fall in temperature of the gas during the stage from C to D. [2] (d) Explain using Fig. 3.2 wh