2025 ZHSS Physics Prelim Paper 1 and 2 MS

1 Paper 1 1 C 11 B 21 A 31 B 2 A 12 D 22 B 32 C 3 B 13 D 23 C 33 B 4 C 14 C 24 B 34 B 5 A 15 D 25 C 35 A 6 D 16 B 26 A 36 A 7 C 17 A 27 C 37 D 8 B 18 C 28 B 38 C 9 D 19 B 29 A 39 B 10 D 20 B 30 A 40 B

2 Paper 2 Section A Questi on Answers Marks 1(a) B1: t = 0 - 10 s B1: t = 10 - 22 s 1(b) a = (0 - 15)/10 = -1.5 m/s2 deceleration = 1.5 m/s2 A1 1(c) Distance travelled = area under the graph = 0.5 × 10 × 15 + 0.5 × 12 × 24 = 219 m Average speed = total distance / total time = 219 / 22 = 10 m/s (2 s.f.) C1: showing evidence distance = area under the graph A1 2(a) • Moving air molecules collide with inner wall of container and exerts a force on it. • Since pressure is the force exerted per unit area, the air molecules exert pressure on the surface of wall. B1 B1 (22, -24)

3 2(b) • Using Newton’s third law, downwards force of water on the rocket is equal to the upwards force of rocket on the water. • Using Newton’s second law, this upwards force is larger than sum of weight and air resistance. Positive net force is upwards. B1 B1 2(c) • The weight of the rocket decreases since water is expelled. • As rocket accelerates upwards, the air resistance increases. • Pressure (of air) decreases • Less water expelled per second / water expelled at slower speed B2: Any 2 answe rs 3(a) Product of force and perpendicular distance between pivot and line of action of force. B1 3(b) Moment = F × d = 80 × 0.90 = 72 Nm A1 3(c) Pivot: worker’s shoulder ACW moment of weight of bucket = F × d = 87 × 1.3 = 113.1 Nm CW moment of weight of ladder = 72 Nm ACW > CW. Therefore the moment due to force L must be CW so ladder can be balanced. ACW = CW 113.1 = 72 + force at L × 0.54 force at L = 76 N Direction: downwards C1 A1 B1 4(a) Energy cannot be created or destroyed. It can only be transferred from one store to another such that the total energy in isolated system remains constant. B1 4(b) Decrease in Ep = Increase in Ek mgh = 0.5mv2 10 × 0.45 = 0.5 × v2 v = 3.0 m/s or 3 m/s C1 A1 4(c) • No, she is incorrect. Not enough (kinetic) energy (at C) to travel beyond D / to top of circle or more Ep needed originally to travel beyond D / to top of circle or Ep gained cannot be greater than original Ep (transferred to Ek) • Car stops at D and goes backwards OR maximum height is D/0.45m/level of A B1 B1 5(a) • Conduction of heat from the heater to the man via air molecules. • Infra-red heat/radiation from the heater to the man B1 B1 5(b) Shiny surface r