MI 23M1PrelimQP (H2 PHYSICS P2)

Class Adm No Candidate Name: This document consists of 25 printed pages and 1 blank page. [Turn over 2023 Preliminary Examinations Pre-University 3 H2 PHYSICS 9749/02 Paper 2 Structured Questions 14 September 2 hours Candidates answer on the Question Paper No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Do not turn over this page until you are told to do so. Write your full name, class and Adm number in the spaces at the top of this page. Write in dark blue or black pen on both sides of this booklet. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. The use of an approved scientific calculator is expected, where appropriate. Answer all questions. The number of marks is given in brackets [ ] at the end of each question or part question . For Examiner’s Use 1 / 6 2 / 7 3 / 7 4 / 8 5 / 9 6 / 9 7 / 14 8 / 20 Presentation Total / 80

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4 Answer all questions in the spaces provided. 1 (a) The final velocity v, initial velocity u, acceleration a and displacement s of a body moving in a straight line at uniform acceleration is related by the equation Show that this equation is homogenous. [2] (b) A student measures the three dimensions of a solid cube: width = 1.99 cm ± 1%, length = 1.95 cm ± 1%, height = 2.02 cm ± 1%. The manufacturer of the cube quotes the density of the material used for the cube as (1.24 ± 0.05) g cm−3. Determine the mass of the cube. Express the mass of the cube together with its uncertainty. mass = ( ± ) g [4]

5 [Turn over [Total: 6] 2 A skateboarder starts from rest at point A as shown in Fig. 2.1. Fig. 2.1 The skateboarder reaches a speed of 17 m s–1 at point B. Consider the skateboarder to be a point mass of 65 kg and ignore the effects of friction and air resistance. (a) Calculate the height difference, h, between point A and point B. h = ……………………… m [1] (b) The skateboarder takes off at point B, travelling horizontally with a velocity of 17 m s– 1. He lands at point C after being in the air for 1.6 s. (i) Calculate vv, the vertical component of his velocity, just before landing at point C.

6 vv = …………………… m s-1 [2] (ii) On Fig. 2.2, sketch the variation with time of the vertical component of the velocity vv of the skateboarder from point B to point C. Fig. 2.2 [ 1 ] (iii ) Show that the magnitude of the resultant velocity just before landing at point C is 23 m s-1. [ 1 ] (c) Explain why it is safer for the skateboarder to land on a downward slope than on a horizontal surface. [2]

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8 3 (a) (i) State Archimedes’ principle. ……………………………………………………………………………………………. ……………………………………………………………………………………………. ………………………………………………………………………………………….[1] (ii) Explain why an object submerged in a fluid experiences upthrust. ……….…………………………………………………………………………………… ……………………………………………………………………………………………. ……………………………………………………………………………………………. ………………………………………………………………………………………….[2] (b) A mini submarine has a mass of 4800 kg and total volume 5.0 m3. To dive into the sea, it takes on mass in the form of seawater into its ballast tank. Fig. 3.1, Fig. 3.2 and Fig. 3.3 show a simplified cross sectional diagram of the mini submarine when it is at the surface of the sea, diving and submerged respectively. Fig. 3.1 Fig.3.2 Fig. 3.3 seawater air ballast tank ballast tank are open and water enters

9 [Turn over Calculate the mass of seawater that the fully submerged mini submarine must take on if it is to descend at a constant speed, when the average resistive force acting on it is 1100 N. Assume the density of seawater is 1030 kg m−3. mass of seawater = ……………………………… kg [3] (c) Calculate the pressure at a sea depth of 200 m. Assume the atmospheric pressure is 1.01 × 105 Pa. pressure = ……………………………… Pa [1] [Total: 7]

10 4 A cyclist made a left turn on a rough level road surface at a constant speed v, as shown in Fig. 4.1. The total mass of the bicycle and rider is m and their combined centre of gravity is at G. Fig. 4.1 (a) In Fig. 4.1, draw and label all the forces acting on the system of the cyclist and his bicycle. Ignore forces parallel to the direction of motion. [2] (b) If the rider is negotiating a turn with a radius of curvature of 55 m, the total mass of the rider and bicycle is 80 kg, and the friction provided by the road surface is 70 N, calculate the speed with which he is turning. speed = ………………….. m s−1 [1]