ACJC 2022 Prelim P1

This paper consists of 16 printed pages Anglo-Chinese Junior College Physics Preliminary Examination Higher 2 PHYSICS Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet 9749/01 14 September 2022 1 hour READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name and index number on the Answer Sheet provided. There are thirty questions in this section. 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 Question Paper. The use of an approved scientific calculator is expected, where appropriate.

2 Anglo-Chinese Junior College 2022 J2 H2 9749 Paper 1 Preliminary Examination DATA AND FORMULAE Data speed of light in free space, c = 3.00  108 m s−1 permeability of free space, o = 4  10−7 H m−1 permittivity of free space, o = 8.85  10−12 F m−1 (1/(36))  10–9 F m–1 elementary charge, e = 1.60  10−19 C the Planck constant, h = 6.63  10−34 J s unified atomic mass constant, u = 1.66  10−27 kg rest mass of electron, me = 9.11  10−31 kg rest mass of proton, mp = 1.67  10−27 kg molar gas constant, R = 8.31 J K−1 mol−1 the Avogadro constant, NA = 6.02  1023 mol−1 the Boltzmann constant, k = 1.38  10−23 J K−1 gravitational constant, G = 6.67  10−11 N m2 kg−2 acceleration of free fall, g = 9.81 m s−2

3 [Turn over Anglo-Chinese Junior College 2022 J2 H2 9749 Paper 1 Preliminary Examination Formulae uniformly accelerated motion, s = ut + 2 1 at 2 v 2 = u 2 + 2as work done on/by a gas, W = p V hydrostatic pressure, p =  g h gravitational potential,  = − Gm r temperature T/K = T/oC + 273.15 pressure of an ideal gas p = 21 3 Nm c V  mean translational kinetic energy of an ideal gas molecule, E = 3 2 kT displacement of particle in s.h.m., x = xo sin t velocity of particle in s.h.m., v = vo cos t =   22 oxx − electric current I = Anvq resistors in series, R = R1 + R2 +  resistors in parallel, 1/R = 1/R1 + 1/R2 +  electric potential, V = 4 o Q r alternating current/voltage, x = xo sin t magnetic flux density due to a long straight wire B = 2 o d   I magnetic flux density due to a flat circular coil B = 2 oN r  I magnetic flux density due to a long solenoid B = on I radioactive decay, x = xo exp(−t) decay constant,  = 12 ln2 t

4 Anglo-Chinese Junior College 2022 J2 H2 9749 Paper 1 Preliminary Examination 1 Which estimate is not realistic? A The power of a computer laptop is 50 W. B The kinetic energy of a car is 100 MJ. C The mass of a sheet of A4 paper is 5 g. D The heating element of an iron has a temperature of 500 K. 2 A cannon ball is launched at an angle  above the horizontal with an initial kinetic energy E. Assume air resistance is negligible. What is the kinetic energy of the cannon ball at the top of its trajectory? A E cos  B E sin2  C E cos2  D E 3 In the presence of air resistance, a cyclist and his bicycle of total mass 80.0 kg is able to coast down a smooth slope at a constant speed of 1.4 m s–1 as shown below. The air resistance is directly proportional to the cyclist’s speed. What is the additional force that the cyclist must apply in order to descend the same slope at a steady speed of 5.5 m s–1? A 200 N B 340 N C 2200 N D 3800 N 5°

5 [Turn over Anglo-Chinese Junior College 2022 J2 H2 9749 Paper 1 Preliminary Examination 4 A light spring of natural length 10.0 cm is attached to the floor of a container. A mass is placed on top of the spring. When the container is lifted upwards at a constant speed, the length of the spring is 7.5 cm. The container then moves upwards with a constant deceleration of 2.0 m s−2. What is the new length of the spring? A 7.0 cm B 8.0 cm C 12.0 cm D 13.0 cm 5 A ball of mass 140 g is moving towards the ground at an angle of 25°. It hits the ground at 20 m s−1 and bounces off with a speed of 15 m s−1 at an angle of 20°. What is the magnitude of the impulse exerted on the ball? A 1.9 N s B 2.0 N s C 4.9 N s D 32 N s 6 Three blocks X, Y and Z of masses m, 2m and 3m respectively, are accelerated along a smooth horizontal surface by a force F applied to block X as shown in the diagram below. What is the force exerted on Y by X? A 1 6 F B 2 1 F C 5 6 F D F X Y Z F

6 Anglo-Chinese Junior College 2022 J2 H2 9749 Paper 1 Preliminary Examination 7 A uniform beam of 10 kg is resting against a rough wall at an angle of 60° to it as shown in the figure below. It is attached to an inextensible string which is fixed to the wall at an angle of 30° to the vertical. What is the tension T in the string? A 85 N B 110 N C 130 N D 170 N 8 A small mass is placed at point P on the in ner surface of a smooth hemisphere as shown in the diagram below. It has an initial gravitational potential energy E and is released from rest at point P. The mass has a speed of 4.0 m s−1 when it reaches the lowest point at T. Take the gravitational potential energy at T to be 0. The diagram shows the speeds of the mass at points Q, R and S as it slides down. Assuming air resistance is negligible, at which point does the mass possess 75% of its initial gravitational potential energy? A Q B R C S D None of the points wall string beam 60° 30°

7 [Turn over Anglo-Chinese Junior College 2022 J2 H2 9749 Paper 1 Preliminary Examination 9 A tape unwinds with speed v from a roll rotating about a fixed axis with constant angular velocity. The radius of the roll r is decreasing at a steady rate. Which of the following graphs best represents the variation with time t of the speed v of the tape? A B C D 10 A satellite of mass 150 kg is launched into a geostationary orbit around the Earth. The Earth has a radius of 6.4  103 km and a mass of 6.0  1024 kg. Which statement is correct? A The satellite need not be above the equator. B The satellite is launched in the westerly direction. C The height of the orbit from the surface of the Earth is 4.23  107 m. D All geostationary satellites must have the same orbital radius and linear speed. v r t 0 v t 0 v t 0 v t 0 v

8 Anglo-Chinese Junior College 2022 J2 H2 9749 Paper 1 Preliminary Examination 11 A binary star is a system of two stars that orbit around each other with angular velocity  about their centre of mass. The stars have masses M and 3 M respectively and the distances of stars from their centre of mass are d and D respectively. Not to scale Which expression gives the total kinetic energy of the two stars? A 2 3 8 GM D B 2 2 GM D C 2 3 2 GM D D 2 2GM D 12 A 50 g piece of wood placed next to a 100 g steel bar is at the same temperature as the steel bar. The steel bar is in thermal equilibrium with a 5.0 g piece of paper placed some distance away from it. A student who touched the three objects remar