(ACJC) 2024 J2 H2 Physics Prelim P2

This paper consists of 26 printed pages Anglo-Chinese Junior College Physics Preliminary Examination Higher 2 CANDIDATE NAME CLASS CENTRE NUMBER S 3 0 0 4 INDEX NUMBER PHYSICS Paper 2 Structured Questions Candidates answer on the Question Paper. No Additional Materials are required. 9749/02 22 August 2024 2 hours READ THESE INSTRUCTIONS FIRST Write your name, class and index number in the spaces at the top of this page. Write in dark blue or black pen on both sides of the paper. You may use an HB pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, glue or correction fluid. The use of an approved scientific calculator is expected, where appropriate. Answer 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 Examiners’ use only 1 / 6 2 / 9 3 / 7 4 / 12 5 / 12 6 / 14 7 / 20 Total / 80

2 Anglo-Chinese Junior College 2024 J2 H2 9749 Paper 2 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 2024 J2 H2 9749 Paper 2 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   magnetic flux density due to a flat circular coil B = 2 oN r  magnetic flux density due to a long solenoid B = on radioactive decay, x = xo exp(−t) decay constant,  = 12 ln2 t

4 Anglo-Chinese Junior College 2024 J2 H2 9749 Paper 2 Preliminary Examination For Examiner’s Use Answer all the questions in the spaces provided. 1 (a) Distinguish between precision and accuracy. ……………………………………………….……….…………………………………… ……………………………………………….……….…………………………………… ……………………………………………….……….…………………………………… ………………………………………………………….……………………………… [2] (b) A simple pendulum consist s of a mass attached to a light inextensible string of length L. The pendulum is secured to a fixed point and made to undergo oscillations when displaced by a small angle. The acceleration of free fall g can be found by the following equation: 2 LT g= where T is the period of oscillation. The following data is given: L = 50.0 ± 0.2 cm T = 1.42 ± 0.01 s (i) Determine g with its associated uncertainty. Give your answer to an appropriate number of significant figures. g = …………..……… ± …………..……… m s−2 [3]

5 [Turn over Anglo-Chinese Junior College 2024 J2 H2 9749 Paper 2 Preliminary Examination For Examiner’s Use (ii) When finding period T using a stopwatch, it is a good practice to time a large number of oscillations such that the total time taken is more than 20 seconds. Explain why this should be done. ….…………………………………………………………………………………… ….…………………………………………………………………………………… …………………………………………………………………………………… [1] [Total: 6]

6 Anglo-Chinese Junior College 2024 J2 H2 9749 Paper 2 Preliminary Examination For Examiner’s Use 2 A stone is projected vertically at a velocity of u from the edge of a building. The stone reaches a maximum height of 27 m above the top of the building and falls down to the ground below. Take the upward direction as positive. Fig. 2.1 (a) (i) Assume that air resistance is negligible. 1. Show that u is 23 m s−1. [2]

7 [Turn over Anglo-Chinese Junior College 2024 J2 H2 9749 Paper 2 Preliminary Examination For Examiner’s Use 2. The stone hits the ground after 6.0 s. On Fig. 2.2, sketch the variation with time t of the velocity v from the time the stone is projected at t = 0 s until t = 6.0 s . Label the axes with appropriate values. Fig. 2.2 [2] (ii) In reality, air resistance is not negligible. On Fig. 2.2, sketch the variation with time t of the velocity v of the stone till 6.0 s. Label the graph R. [2] .

8 Anglo-Chinese Junior College 2024 J2 H2 9749 Paper 2 Preliminary Examination For Examiner’s Use (b) An elastic net is now placed on top of the ground to catch the stone, so that it does not hit the ground. To simplify the analysis, Fig. 2.3 shows two identical springs and a rigid container which are used to model the elastic net. Assume the masses of the springs and rigid container to be negligible. The stone hits the rigid container when the springs are at length x0 and subsequently, the springs stretch by a maximum extension of xs. Fig. 2.3 On Fig. 2.4, sketch graphs of the following quantities to show the variation with extension x of the spring. (i) (ii) (iii) The kinetic energy of the stone and container. Label this graph K. The gravitational potential energy (GPE) of the stone and container. Take GPE to be zero at the lowest point of the motion. Label this graph G. The elastic potential energy of the spring. Label this graph E. Fig. 2.4 [3] [Total: 9]

9 [Turn over Anglo-Chinese Junior College 2024 J2 H2 9749 Paper 2 Preliminary Examination For Examiner’s Use 3 A uniform, rectangular canopy is 1.30 m wide. It is kept horizontal and in equilibrium by two steel cables. Fig. 3.1 shows the canopy fixed to the wall by a hinge. Fig. 3.1 (not to scale) One end of each cable is attached to the canopy at a distance of 0.800 m from the wall. The other ends are attached to the wall at a distance of 0.600 m above the canopy. The tension in each cable is 47.5 N. (a) State the two conditions for an object to be in equilibrium. 1. ………………………………………………………………………………………….. …………………………………………………………………………………………….. 2. ………………………………………………………………………………………….. ……………………………………………………………………………...………….. [2] (b) Determine the mass of the canopy. mass = …………..……… kg [3]

10 Anglo-Chinese Junior College