NJC 2022 Prelim P1

[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 14 September 2022 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 Answer Sheet in the spaces provided unless this has been done for you. 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 Answer Sheet. Read the instructions on the Answer Sheet 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. The OAS index number is in a 5-digit format. The 5-digit format is as follows: 2nd digit and the last four digits of the Reg Number. e.g. 2005011 becomes 05011 This document contains 15 printed pages and 1 blank pages.

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4 1 Which of the following is the best estimate of the kinetic energy of an average National Junior College sprinter? A 25 J B 1500 J C 3500 J D 11000 J 2 A student makes measurements from which he calculates the speed of sound as 327.66 m s –1. He estimates that his result is accurate to ± 3%. Which of the following gives his results reduced to the appropriate number of significant figures? A 300 m s–1 B 320 m s–1 C 328 m s–1 D 330 m s–1 3 A car accelerates uniformly from rest for 16 s along a straight track. What is the ratio distance travelled between 8 s and 16 s distance travelled between 0 s and 8 s ? A 1 B 2 C 3 D 4 4 An object is projected with velocity 35 m s –1 at an angle of 40 o to the horizontal. Air resistance is negligible. What is the speed of the object after 4.0 s? A 26 m s–1 B 32 m s–1 C 67 m s–1 D 70 m s–1 height distance 35 m s–1 40o 0 0

[Turn over 5 5 A trolley of mass 0.50 kg moves with a certain acceleration down a runway which is inclined to the horizontal at 15. If the angle of inclination is increased to 20 , the acceleration of the trolley would be doubled. What is the frictional force, assumed to be the same in both cases, acting on the trolley? A 0.12 N B 0.41 N C 0.86 N D 4.9 N 6 A 5.00 kg object moves at 15.0 m s−1 makes a head-on collision with a 10.0 kg object which was at rest. Both the objects coalesce and move off with a common velocity. How much kinetic energy is lost in the collision? A 188 J B 375 J C 563 J D 702 J 7 Oxygen is compressed in the sealed end of a long J -tube by means of a column of mercury open to the atmosphere, as shown. Mercury has density 13.6 × 103 kg m−3 and atmospheric pressure 1.01 × 105 Pa. What is approximate value of pressure of oxygen pressure of atmosphere ? A 1.5 B 2.0 C 2.5 D 3.0

6 8 To inspect the engine of a car, the bonnet, hinged at H, is held open by a strut. The weight of the bonnet acts through its centre of gravity G. Which arrow best represent the approximate direction of the force on the bonnet at the hinge H? 9 A body of mass m moves at constant speed v for a distance s against a constant F. What is the power required to sustain this motion? A mv B ½ mv2 C ½ F s D Fv 10 A mass of 2 kg rotates at a constant speed in a horizontal circle of radius 5 m and the time for one complete revolution is 3 s. The force acting on the mass is A 20π2 3 N B 20π2 9 N C 40π2 9 N D 100π2 9 N

[Turn over 7 11 Two stationary particles of masses M1 and M2 are a distance d apart. A third particle of mass m, lying on the line joining the particles, experiences no resultant gravitational force. What is the distance of this particle of this mass from M1? A d √ M1 M2 B d ( M1 M1+M2 ) C d ( √M1 √M1+√M2 ) D d √ M1 M1+M2 12 The diagram shows two points X and Y at distance L and 2L, respectively, from the centre of the Earth. The gravitational potential at X is – 8 kJ kg–1. What is the gain in gravitational potential energy of a 2 kg mass when it is moved from X to Y? A – 8 kJ B – 4 kJ C + 4 kJ D + 8 kJ 13 Which of the following statements is not correct? A The microscopic potential energy of an ideal gas is zero. B Two bodies in thermal equilibrium have no heat flow between them. C During the melting of ice, there is no increase in temperature. D The average kinetic energy of a gas molecule is proportional to its thermodynamic temperature. Earth X L 2L Y

8 14 An ideal gas is enclosed in a cylinder by a gas -tight, frictionless piston. The gas then undergoes changes along the path as shown in the figure below (not to scale). Which of the following statement is valid? A There is no change in the internal energy of the gas. B Work is done on the gas. C The average kinetic energy of the gas molecules is the same at both states A and B. D Heat is gained by the gas. 15 Which statements about internal energy is correct? A The internal energy of a system depends only on its temperature. B The internal energy of a system can be increased without heating. C When the internal energy of a system is increased, its temperature always rises. D When two systems have the same internal energy, they must be at the same temperature. Pressure /105 Pa Volume /10−2 m3 6 2 3 4 0 A B

[Turn over 9 16 A particle is moving such that the force F on it changes with the distance r from a fixed point as shown. Which graph best shows the relationship between the potential energy Ep of the particle and the distance r? A B C D 17 A sound wave of frequency 400 Hz is travelling in air at a speed of 320 m s−1. What is the difference in phase between two points on the wave 0.2 m apart in the direction of travel? A π 4 rad B π 2 rad C 2π 5 rad D 8π 5 rad

10 18 Water waves of wavelength 2.0 m are produced by two generators, S1 and S2, placed 4 m apart. Each generator, when operated by itself, produces waves which have an amplitude of A at point P as shown in the diagram. When the generators are operating in antiphase, the amplitude of the oscillation at P is A 0 B ½ A C A D 2 A 19 A student blows gently across the top of a piece of glass tubing, the lower end of which is closed by his finger so that the tube gives its fundamental note of frequency f. While blowing, he removes his finger from the lower end. The note he then hears will have a frequency of approximately A 𝑓 4 B 𝑓 2 C 2𝑓 D 4𝑓 20 The diagram shows point charges, each of magnitude Q placed at three corners of a square. What is the direction of the resultant electric field at the fourth corner? –Q –Q –Q A B C D S1 S2 P 4.0 m 3.0 m