DHS 2025 H2 Prelim P3

@ DHS 2025 9749/03 [Turn over Name: Centre/Index Number: Class: DUNMAN HIGH SCHOOL Preliminary Examination Year 6 H2 PHYSICS Paper 3 Longer Structured Questions Candidates answer on the Question Paper 9749/03 26 September 2025 2 hours READ THESE INSTRUCTIONS FIRST Write your class, index number and name at the top of this page Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Section A Answer all questions. Section B Answer any one question. The use of an approved scientific calculator is expected, where appropriate. You may lose marks if you do not show your working or if you do not use appropriate units. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use Section A 1 6 2 8 3 6 4 8 5 12 6 11 7 9 Section B (circle attempted) 8 / 9 20 s.f. -1 Total 80 This document consists of 26 printed pages and 2 blank pages

2 @ DHS 2025 9749/03 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 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 @ DHS 2025 9749/03 [Turn over Formulae uniformly accelerated motion, s = ut + at2 v2 = u2 + 2as work done on/by a gas, W = pV hydrostatic pressure, p = gh gravitational potential,  = −Gm/r temperature, T/K = T/oC + 273.15 pressure of an ideal gas, p = mean translational kinetic energy of an ideal gas molecule, E = displacement of particle in s.h.m., x = x0 sin t velocity of particle in s.h.m., v = v0 cos t =  electric current, I = Anvq resistors in series, R = R1 + R2 + . . . resistors in parallel, 1/R = 1/R1 + 1/R2 + . . . electric potential, V = alternating current / voltage, x = x0 sin t magnetic flux density due to a long straight wire, B = magnetic flux density due to a flat circular coil, B = magnetic flux density due to a long solenoid, B = radioactive decay, x = x0 exp(−t) decay constant,  = 1 2 21 3 Nm cV  kT2 3 22 xxo − r Q o4 0 2 d I  0 2 N r I 0nI 1 2 ln2 t

4 @ DHS 2025 9749/03 Section A Answer all the questions in this section in the spaces provided. 1 (a) Define gravitational field strength at a point. ……………………………………………………………………………….................. ……………………………………………………………………………….................. [1] (b) From Newton’s Law of gravitation and the definition of gravitational field strength, show that the gravitational field strength due to a point mass is given by 2 GMg r= where G is the gravitational constant, M is the mass of the point mass, and r is the distance from the point mass. [2] (c) By reference to the lines of gravitational force near to the surface of the Earth, explain why the gravitational field strength g close to the Earth’s surface is approximately constant. ……………………………………………………………………………….................. ……………………………………………………………………………….................. ……………………………………………………………………………….................. ……………………………………………………………………………….................. ……………………………………………………………………………….................. ……………………………………………………………………………….................. [3] [Total: 6]

5 @ DHS 2025 9749/03 [Turn over 2 (a) State Newton’s second law of motion. ……………………………………………………………………………….................. ……………………………………………………………………………….................. [1] (b) A ball of mass 65 g hits a wall with a velocity of 5.2 m s −1 perpendicular to the wall. The ball rebounds perpendicularly from the wall with a speed of 3.7 m s −1. The contact time of the ball with the wall is 7.5 ms. Calculate, for the ball hitting the wall, (i) the change in momentum, change in momentum = …………………………………. N s [2] (ii) the magnitude of the average force. average force = …………………………………. N [1] (c) (i) For the collision in (b) between the ball and the wall, state how the following apply: 1. Newton’s third law, ………………………………………………………………………………......... ………………………………………………………………………………......... [2] 2. the law of conservation of momentum. ………………………………………………………………………………......... ………………………………………………………………………………......... [1]

6 @ DHS 2025 9749/03 (ii) State, with a reason, whether the collision is elastic or inelastic. ………………………………………………………………………………......... ………………………………………………………………………………......... [1] [Total: 8] 3 (a) State what is meant by the moment of a force. ……………………………………………………………………………….................. ……………………………………………………………………………….................. [1] (b) A traffic light hangs from a uniform metal pole AB, freely pivoted at point A, as shown in Fig. 3.1. The pole is 7.5 m long and has a mass of 8.0 kg. The mass of the traffic light is 12.0 kg. Fig. 3.1 (i) Determine the tension in the horizontal cable CD. Assume the mass of cable CD is negligible. tension = …………………………………. N [2] B C D A 37° 3.8 m

7 @ DHS 2025 9749/03 [Turn over (ii) Determine the force exerted on the metal pole at pivot A. force = …………………………………. N direction: …………………….…………………………………. [3] [Total: 6]

8 @ DHS 2025 9749/03 4 (a) In a space, such as a swimming pool enclosure, water at 30 °C and water vapour, also at 30 °C coexist. (i) State what is meant by internal energy of a system. ………………………………………………………………………………......... ………………………………………………………………………………......... [1] (ii) With reference to your answer in (a)(i), compare the internal energy per unit mass of water and water vapour at the same temperature. ………………………………………………………………………………......... ………………………………………………………………………………......... ………………………………………………………………………………......... ………………………………………………………………………………......... [2] (b) A helium balloon containing 15000 m 3 of helium at a temperature of 288 K was laun