2024 MSH SC(PHY) PRELIM P2

O Level Centre Number/ Index Number Class Name MARIS STELLA HIGH SCHOOL PRELIMINARY EXAMINATION SECONDARY FOUR SCIENCE (PHYSICS, CHEMISTRY) 5086/02 Paper 2 Physics 22 August 2024 1 hour 15 minutes Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your class, index number and name on all the work you hand in. You may use an HB pencil for any diagrams, graphs, tables or rough working. Write in dark blue or black pen. Do not use staples, paper clips, glue or correction fluid. 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. Section A Answer all the questions. Write your answers in the spaces provided on the question paper. Section B Answer one question. Write your answers in the spaces provided on the question paper. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use Section A 55 Section B 10 Total 65 This document consists of 19 printed pages inclusive of this cover page.

2 Section A Answer all questions in the spaces provided. 1 Fig. 1.1 shows a child sitting on a sledge on a snow-covered hill of constant slope. Fig. 1.1 (not to scale) At time t = 0 s, the child and the sledge begin to move down the hill in a straight line. When the child sees a wall ahead, he applies the brake. The child and sledge continue to travel in a straight line until they come to a stop. (a) Fig. 1.2 shows the child’s speed throughout his descent. Complete the speed-time graph of the child in Fig. 1.2 using the points provided. [2] Fig. 1.2

3 (b) At t = 26 s, the front of the sledge is 35 m from the wall and the child and sledge begin to decelerate. The mass of the child is 46 kg and the mass of the sledge is 9.0 kg. (i) Calculate the energy in the child’s kinetic store at t = 26 s. energy in kinetic store = J [2] (ii) Determine the size of the child’s deceleration. deceleration = m/s2 [2] (iii) Calculate the resultant force on the child and the sledge as they decelerate. resultant force = N [2] (iv) State the energy transfer that is taking place as the child and sledge decelerate. [2] [Total: 10]

4 2 A student sets up the following apparatus in Fig. 2.1 to measure the density of an unknown liquid A. The liquids do not mix. Fig. 2.1 XY is the horizontal line at the same height as the junction between liquid A and water. The cross-sectional area of the U-tube is 2.5 × 10-4 m2, the density of water is 1000 kg/m3 and the gravitational field strength is 10 N/kg. (a) Calculate (i) the mass of water above line XY. mass of water above XY = kg [2] (ii) the pressure due to the water above line XY. pressure = N/m2 [2]

5 (b) The pressure due to liquid A above line XY is the same as the pressure due to water above line XY. Calculate the density of liquid A. density of liquid A = kg/m3 [2] (c) The set up has a risk of toppling over. Suggest how the set up can be modified to increase its stability. [1] [Total: 7]

6 3 A student invents a machine to measure the force of the wind. A large piece of light-weight material is used as a wind-catcher and is attached to the top of a mast. An instrument A is used to measure the turning force and is attached to the bottom of the mast. Instrument B (not shown in figure) is used to measure the heights of the wind-catcher to the pivot and instrument A to pivot respectively. The mast is free to rotate about a pivot as shown in Fig. 3.1 Fig. 3.1 (not to scale) (a) Suggest the instruments A and B used in the machine. (i) instrument A [1] (ii) instrument B [1] (b) Instrument A is attached 0.25 m from the pivot. On a windy day, the reading on instrument A is 52.0 N when the mast is vertical. (i) State the principle of moments. [2]

7 (ii) The wind-catcher is attached 5.0 m from the pivot. Calculate the force from the wind when the mast is vertical. force from the wind = N [2] [Total: 6] 4 Fig. 4.1 shows the structure of a water cooler that is used to supply cold water to the workers in a hot office. Fig. 4.1 When the tap is opened, water at room temperature from the reservoir flows down into the tank. Cold water from the tank flows through the plastic pipe and out of the tap. Cold liquid from the refrigeration unit is pumped through the copper pipe and thermal energy passes through the copper to this liquid. (a) State the method of heat transfer through the copper pipe and suggest why copper is a suitable material for the pipe. [2]

8 (b) Water in the plastic container remains at room temperature. Explain why the refrigeration unit is positioned near the top of the tank. [2] (c) Describe the motion of the molecules in a liquid as temperature of the liquid decreases. [2] [Total: 6]

9 5 The apparatus shown in Fig. 5.1 is used to find the speed of sound in air. Fig. 5.1 Two microphones 2.0 m apart are connected to an electronic timer. The metal block is hit with a hammer to produce a short ‘pulse’ of sound containing different frequencies and wavelengths. Microphone 1 detects the pulse of sound and starts the electronic timer. Microphone 2 detects the pulse of sound and stops the timer. The electronic timer measured 5.88 ms. (a) (i) Calculate the speed of sound in air using the following equation: 𝑠𝑝𝑒𝑒𝑑 = 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑡𝑖𝑚𝑒 speed of sound in air = m/s [1] (ii) One of the waves produced has a frequency of 485 Hz. Calculate the wavelength of this wave. wavelength = m [2]

10 (iii) All the waves within this pulse of sound reach microphone 2 in the same amount of time. Explain why. [1] (b) The set up is modified such that a block of metal 2.0 m wide is placed between the two microphones and both microphones are touching each end of the metal block. The experiment is then repeated. Explain if the timer would have a reading greater than or smaller than what was measured in Fig. 5.1. [1] [Total: 5]