SASS 2025 sec 4E prelim paper 2

3 Prelim Examination 2025/4Exp/Physics paper 2 [Turn over Section A Answer all questions. 1 A ball is released from rest at point A and moves along a smooth track ABCDE as shown in Fig. 1.1. The ball is shown at point A and as it passes point B. The ball is always in contact with the track and air resistance is negligible. Fig. 1.2 shows the distance−time graph for the ball as it moves from A to E.

4 Prelim Examination 2025/4Exp/Physics paper 2 [Turn over (a) (i) On Fig. 1.2, mark: • with the letter P one point where the ball accelerates • with the letter Q one point where the ball has constant speed. [2] (ii) Determine the speed of the ball at point X on Fig. 1.2. Show your working. speed = ....................................[2] (b) The speeds of the ball at A, B, C and D are vA, vB, vC and vD respectively. Arrange these four speeds from slowest to fastest. slowest fastest [1]

5 Prelim Examination 2025/4Exp/Physics paper 2 [Turn over 2 Fig. 2.1 shows a uniform plank AB of length 2.0 m suspended from two ropes X and Y. The weight W of the plank is 210 N. The force in rope X is P. The force in rope Y is Q. (a) State, in terms of P, the moment of force P about B. ........................................................................................................................[1] (b) Calculate: (i) the moment of W about B moment = ...........................................................[1] (ii) the force P force P = ...........................................................[2] (iii) the force Q. force Q = ...........................................................[2]

6 Prelim Examination 2025/4Exp/Physics paper 2 [Turn over 3 (a) State what is meant by the principle of conservation of energy. ............................................................................................................................ ........................................................................................................................[1] (b) Fig. 3.1 shows a girl throwing a heavy ball. (i) State the energy changes that take place from when the girl begins to exert a force on the ball until the ball hits the ground and stops moving. ................................................................................................................. ................................................................................................................. ................................................................................................................. ................................................................................................................. ................................................................................................................. .............................................................................................................[2]

7 Prelim Examination 2025/4Exp/Physics paper 2 [Turn over (ii) The mass of the ball is 4.0 kg. The girl exerts a force on the ball for 0.60 s. The speed of the ball increases from 0 m/s to 12 m/s before it leaves the girl’s hand. Calculate the average resultant force exerted on the ball. average resultant force = ..........................................................[2]

8 Prelim Examination 2025/4Exp/Physics paper 2 [Turn over 4 A small aircraft takes off from the horizontal deck of a ship. Before taking off, the aircraft is held in place by a holdback bar. When the holdback bar is released, the aircraft is pulled along the deck by a steam-powered piston as shown in Fig. 4.1. The steam exerts a high pressure on the piston. (a) (i) Explain, using ideas about particles, how the steam creates a pressure on the piston. ................................................................................................................. ................................................................................................................. ................................................................................................................. ................................................................................................................. ................................................................................................................. ................................................................................................................. .............................................................................................................[2] Fig 4.1 (not to scale)

9 Prelim Examination 2025/4Exp/Physics paper 2 [Turn over (ii) Explain why the pressure on the piston increases as the temperature of the steam increases. ................................................................................................................. ................................................................................................................. ................................................................................................................. ................................................................................................................. ................................................................................................................. .............................................................................................................[2] (b) When the pressure is high enough, the holdback bar is released. The steam pushes the piston along the pipe shown in Fig. 4.1. The piston has a cross- sectional area of 0.30 cm2. The pressure of the steam in the tank is 2.1 × 106 Pa. Atmospheric pressure is 1.0 × 105 Pa. Determine the resultant force on the piston caused by the pressure difference. Show your working. force = .................................................... [2]

10 Prelim Examination 2025/4Exp/Physics paper 2 [Turn over 5 The virtual reality headset in Fig. 5.1 contains a display and a lens, as shown in Fig. 5.2. The display is the object for the lens. The lens acts as a magnifying glass and forms a virtual image of the display. (a) (i) Describe where the display must be positioned relati