NJC 2022 SH1 Promo Paper 2 Qn

1 NATIONAL JUNIOR COLLEGE SENIOR HIGH 1 PROMOTIONAL 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 30 September 2020 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 / 9 2 / 6 3 / 6 4 / 8 5 / 10 6 / 10 7 / 15 8 / 16 Total (80m) This document consists of xx printed pages and x blank page.

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4 Answer all the questions in the spaces provided. 1 (a) (i) Distinguish between random and systematic error. ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… [3] (ii) Explain why using a graph a nd drawing line of best fit for the different points will reduce the random error. ……………………………………………………………………………………………… ……………………………………………………………………………………………… [1] (b) A ball approaches a ramp with an inclination of 30°. It hits the surface of the ramp at a speed of 5.0 m s −1 at 45° to the normal and bounces off with a speed of 5.0 m s−1 as shown in Fig. 1.1. Fig. 1.1 Determine the change in velocity of the ball. magnitude of change in velocity = ……………………… m s−1 [2] direction of change in velocity is ……………………… ° with respect to the horizontal [1]

5 (c) A physical equation is of the form −= 3 12()r P PQk L where k is a constant, r = (1.55  0.03) mm, P1 = (125  1) kPa, P2 = (100  1) kPa, L = (120  5) m. Determine the fractional uncertainty of Q? fractional uncertainty of Q = ……………………… [2] [Total: 9]

6 2 Popcorn is produced in a shallow pan. One piece of popcorn is projected out of the pan from the base of the pan. Fig. 2.1 shows the trajectory of this piece of popcorn. Fig. 2.1 The piece of popcorn reaches a maximum height of 56.0 cm above the base of the pan. You may assume air resistance is negligible. (a) (i) Show that the vertical component uv of the initial velocity of the piece of popcorn is about 3.3 m s-1. [1] (ii) The piece of popcorn lands at the same level as its starting point