NJC H2 Physics Prelim P2 Ans

[Turn over NATIONAL JUNIOR COLLEGE SENIOR HIGH 2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME SUBJECT CLASS REGISTRATION NUMBER PHYSICS Paper 2 Structured Questions Candidate answers on the Question Paper. No Additional Materials are required. 9749/02 24 August 2023 2 hours READ THE INSTRUCTION FIRST Write your subject class, registration number and name on all the work you hand in. Write in dark blue or black pen on both sides of the paper. You may use a 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. Answers all questions. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use 1 / 10 2 / 10 3 / 8 4 / 6 5 / 6 6 / 10 7 / 10 8 / 20 Total (80m)

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4 1 A sphere is projected horizontally. The sphere is photographed at intervals of 0.10 s. The images of the sphere are shown against a grid in Fig 1.1. Air resistance is negligible. (a) Use data from the diagram to determine the acceleration of free fall. acceleration = ……………. m s-2 [2] g = 2s/t2 s = 1.75 m, t = 0.6 s C1 g = 9.7 m s-2 A1 (b) Explain how your choice of the data point from Fig 1.1 helps to improve the reliability of your calculation in (a). …………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………………. …………………………………………………………………………………………………………………... [2] Fig 1.1

5 [Turn over % uncertainty = absolute uncertainty/ data point. M1 Hence the larger the data point, the smaller the % uncertaintiy since the absolute uncertainty is fixed. Hence more reliable. A1 (c) Determine the speed of the sphere 1.2 s after release. speed = ………………. m s-1 [4] horizontal speed = 3.2 m s-1 C1 use of v = gt or s = 1/2 gt2 vertical speed = 11.6 or 11.7 m s-1 C1 use of Pythagoras’ theorem; M1 speed = 12 m s-1 A1 (d) On the grid, draw the path of the sphere assuming air resistance is not negligible. [2] line always to left of spheres; B1 becoming more vertical/ steeper; B1 [Total: 10]

6 2 (a) A prototype space shuttle attached to a rocket stands vertically on its launching pad. The total mass of the spaceship and rocket (inclusive of the mass of a man in it and its fuel) is 8.5 × 10 4 kg. On ignition, gas is ejected from the rocket at a speed of 6.0 × 103 m s–1 relative to th