2022 JSS Phy Prelims P2

O JURONG SECONDARY SCHOOL 2022 GRADUATION EXAMINATION 2 SECONDARY 4 EXPRESS CANDIDATE NAME CLASS INDEX NUMBER PHYSICS 6091/02 Paper 2 Theory 26 August 2022 1 hour 45 min Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Do not open this booklet until you are told to do so. Section A Answer all questions. Write your answers in the spaces provided on the Question Paper. Section B Answer all questions. Question 11 has a choice of parts to answer. Write your answers in the spaces provided on the Question Paper. At the end of the examination, fasten all your work securely together. The number of marks is given in the brackets [ ] at the end of each question or part question. For Examiner’s Use Paper 1 (30%) MCQ [40 marks] Paper 2 (50%) SECTION A [50 marks] SECTION B [30 marks] SUB-TOTAL [80 marks] Paper 3 (20%) PRACTICAL [40 marks] OVERALL % [100 %] This document consists of 25 printed pages including this page.

2 6091/2/GE2/22 [Turn over] Section A [50 marks] Answer all the questions in this section. 1 A boy rides a sled down a slope. W is the combined weight of the boy and the sled. N is the normal reaction force from the slope on the sled and the boy. R is the resistive force on the boy and the sled. Fig. 1.1 (a) Describe the force that forms an action-reaction pair with N. ………………………………………………………………………………………...... [1] (b) As the boy descends the slope, his velocity increases. Using ideas about forces, explain the effect this has on his acceleration. ……………………………………………………………………………………………… ……………………………………………………………………………………………... ……………………………………………………………………………………..…… [2] (c) The boy wants to go faster down the same slope on his sled. Without modifying the sled, suggest how he can go faster. ………………………………………………………………………………………..…..… ………………………………………………………………………………………..… [1]

3 6091/2/GE2/22 [Turn over (d) The combined weight of the boy and sled is 600 N. The boy is traveling at a constant speed down the slope. By means of a scaled diagram, determine the magnitude of R. force R = …………………………… [3]

4 6091/2/GE2/22 [Turn over] 2 A student is sitting on a chair as shown in Fig. 2.1. Fig. 2.1 The student tips his chair back to the position shown in Fig. 2.2. Fig. 2.2 (a) Explain how the pressure exerted by the chair on the floor in Fig. 2.1 compares with the pressure exerted by the chair in Fig. 2.2. ………………...……………………………………………………………………..…….. ……………………………………………………………………………………..……….. ………………………………………………………………………………………...... [2] (b) Explain why the chair in Fig. 2.2 is unstable. …………………………………………………………………………………………….... ……………………………………………………………………………………..……….. …………………………………………………………………………………….……. [2] (c) In the second experiment, the student blows into a U-tube manometer to measure

5 6091/2/GE2/22 [Turn over the pressure of his breath. Atmospheric pressure is 1.0 x 105 Pa. Density of mercury is 13 600 kg/m3. Gravitational field strength is 10 N/kg. Fig. 2.3 shows the manometer when he is blowing into the manometer. Fig. 2.3 Determine the pressure of his breath. pressure = …………………………… [2] 3 The setup in Fig. 3.1 can be used to investigate the loss of energy when a ball is dropped 0.05 m U-tube manometer mercury

6 6091/2/GE2/22 [Turn over] from a certain height. Fig. 3.1 The ball of mass 1.5 kg is dropped from height h. The following graph showing the motion of the ball is obtained. Fig. 3.2 (a) Describe the energy change of the ball between time = 0 to 0.6 s.

7 6091/2/GE2/22 [Turn over ……………………………………………………………………………..……………….. ………………………………………………………………………………..…………….. ………………………………………………………………………………….………. [2] (b) Take gravitational field strength g = 10 N/kg. From Fig. 3.2, determine (i) the gravitational potential energy of the ball before it is released. gravitational potential energy = ……………………. [2] (ii) the power of the ball on its first impact with the floor. power = ………….……………. [1] (c) Ignoring air resistance, explain why the graph during the fall of the ball is not linear. …………………………………………………………………………..………………….. …………………………………………………………………………….……………. [1]

8 6091/2/GE2/22 [Turn over] 4 A balloon containing some gas is placed inside a chamber as shown in Fig. 4.1. Fig. 4.1 (a) Explain, using ideas about molecules, how the gas inside the balloon exerts a pressure on its inner surface. ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ………………………………………………………………………………………….. [2] (b) Air is now pumped out. Explain, using ideas about molecules, why the volume of the balloon increases. ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ………………………………………………………………………………………….. [2]

9 6091/2/GE2/22 [Turn over 5 Fig. 5.1 represents the electromagnetic spectrum. (a) State the name of the component that has a greater frequency than B. ………………………………………………………………………………………….. [1] (b) Describe one use of X-rays and its effect on living tissues and cells. ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ………………………………………………………………………………………….. [2] Fig. 5.1

10 6091/2/GE2/22 [Turn over] (c) Ultrasound and X-rays are both used in medical imaging. To produce the image of an unborn child, an ultrasound emitter and receiver are placed close together on the mother’s skin. Fig. 5.2 shows pulses detected by the receiver. Fig. 5.2 Pulse A is the emitted pulse and pulse B is the first pulse that returns from the unborn child. The average speed of ultrasound in human tissue is 1500 m/s. Calculate the distance between the emitter and the child. distance = ......................................................... [3]