Bedok Green Prelim P2

© BGSS 2024 [Turn Over 2 For examiner’s use SECTION A [ 70 marks ] Answer all questions in this section. 1 Fig. 1.1 shows three forces acting on an object and keeping it in equilibrium. Fig. 1.1 Given that F1 is perpendicular to the vertical, determine the forces F1 and F2. Include a labelled scaled vector diagram in your answer. scale: ………………………………….. F1 = ……………………….. F2 = ………………………..[4] 30° F2 F1 10 N vertical

© BGSS 2024 [Turn Over 3 For examiner’s use 2 Car A is travelling at a uniform speed of 10 m/s. The driver sees an obstacle at time = 0 s and applies the brakes. Fig. 2.1 shows the speed time graph of car A, starting from the time he first sees the obstacle. Fig. 2.1 (a) Determine (i) the reaction time of the driver in car A, reaction time = …………………..[1] (ii) the deceleration of car A. deceleration = ……………………[2] speed / m/s time / s A B

© BGSS 2024 [Turn Over 4 For examiner’s use (b) At time = 0 s, the driver of car B, travelling at an initial speed of 15 m/s applies the brakes immediately when he first sees the obstacle. The speed-time graph of car B is shown in Fig. 2.1. (i) State which car travelled a longer distance before coming to a complete stop. Give an explanation for your answer. …………………………………………………………………………….. …………………………………………………………………………….. …………………………………………………………………………….. ……………………………………………………..……………………[2] (ii) Using the graph in Fig. 2.1, explain the changes in the braking force exerted by car B. …………………………………………………………………………….. …………………………………………………………………………….. …………………………………………………………………………….. ……………………………………………………..……………………[2]

© BGSS 2024 [Turn Over 5 For examiner’s use 3 Fig. 3.1 shows the presence of gas molecules, in a cylinder. Fig. 3.1 Using the kinetic model of matter, explain the following: (a) When the piston is pushed into the cylinder, the gas pressure increases. …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………[2] (b) The piston is pushed out of the cylinder as temperature of the cylinder increases. …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………[2] gas piston cylinder

© BGSS 2024 [Turn Over 6 For examiner’s use 4 Fig. 4.1 shows ultrasound being used to find the distance between a submarine and an underwater object. Fig. 4.1 Fig. 4.2 shows the trace of the pulse sent from the submarine and the reflected pulses that