NJC H2 Physics Prelim P1 Ans

1 [Turn over NATIONAL JUNIOR COLLEGE SENIOR HIGH 2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME SUBJECT CLASS REGISTRATION NUMBER PHYSICS Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet 9749/01 15 September 2023 1 hour READ THE INSTRUCTION FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, subject class and registration number on the Optical Answer Sheet (OAS) in the spaces provided. There are thirty questions on this paper. Answer all questions. For each question there are four possible answers A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the separate OAS. Read the instructions on the OAS very carefully. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. The use of an approved scientific calculator is expected, where appropriate. Shading of OAS index number OAS index number is in a 5-digit format. The 5 digit format is as follows: 1st digit and the last four digits of the Reg Number. e.g. 2005011 becomes 25011 This document consists of 19 printed pages and 1 blank page.

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4 [Turn over 1 Which definition is correct and uses only quantities rather than units? A Density is mass per cubic metre. B Potential difference is energy per unit current. C Pressure is force per unit area. D Speed is distance travelled per second. Ans: C 2 Which formula could be correct for the speed v of ocean waves in terms of density  of sea- water, the acceleration of free fall g, the height h of the wave and the wavelength ? A v = √gh B v = √g h C v = √g D v = √ g  2 C unit of √g = √(m s-2) m = m s−1 3 A ball, initially at rest, is dropped in the air from a great height. Air resistance is not negligible. Which of the following graphs best shows the variation with time t of the acceleration a of the ball? A B C D 3 C mg – kv =ma As time increases, a drops. Since v is not linear with time because acceleration is not constant therefore must be C

5 [Turn over 4 A lift consists of a passenger car supported by a cable which runs over a light, frictionless pulley to a balancing weight. The balancing weight falls as the passenger car rises. (not drawn to scale) The masses are shown in the table. mass / kg passenger car 1200 balancing weight 1320 passenger 80 What is the magnitude of the force between the passenger and the passenger car when carrying just one passenger and when the pulley is free to rotate? A 12 N B 773 N C 785 N D 797 N 4 D for inextensible cable, the passenger, passenger car and balancing weight moves as one object with the upward motion of the balancing