ACJC 2023 J2 H2 Physics Prelim P2 2

This paper consists of 25 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 23 August 2023 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 / 8 2 / 8 3 / 8 4 / 10 5 / 8 6 / 8 7 / 10 8 / 20 Total / 80

2 Anglo-Chinese Junior College 2023 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 2023 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 2023 J2 H2 9749 Paper 2 Preliminary Examination For Examiner’s Use Answer all the questions in the spaces provided. 1 A student time s the fall of a small metal ball. Data for the time t taken for a ball of mass m to fall a vertical distance h from rest are given in the table below. h 588 ± 1 cm m 10 ± 1 g t 1.1 ± 0.1 s (a) Use the data to determine a value of the acceleration of free fall, g. g = ………………………… m s –2 [2] (b) The student collects 5 more sets of data at different heights. Explain how the student can use the data to get a more accurate value of g. …………………………………………………………………..………………………… ……………………………………………………………………………..……………… …………………………………………………………………..………………………… …………………………………………………………….....…………………………… ……………………………………………………………………………..………...… [2]

5 [Turn over Anglo-Chinese Junior College 2023 J2 H2 9749 Paper 2 Preliminary Examination For Examiner’s Use (c) Use your answer in (a) to determine the loss in gravitational potential energy U for the ball. loss in gravitational potential energy = ………………………… J [1] (d) Hence, express U to an appropriate number of significant figures with its uncertainty. U = …………………… ± …………………… J [3] [Total: 8]

6 Anglo-Chinese Junior College 2023 J2 H2 9749 Paper 2 Preliminary Examination For Examiner’s Use 2 (a) Car A is traveling along a straight path at a constant speed of 8.5 m s–1. When car A passes car B at t = 0 s, car B accelerates uniformly from rest at 2.5 m s–2. (i) Determine the distance travelled by car B when it overtakes car A. distance = ………………………… m [2] (ii) On Fig. 2.1, sketch a well labelled graph to show the variation with time of the displacement of car A and car B. Fig. 2.1 [2]

7 [Turn over Anglo-Chinese Junior College 2023 J2 H2 9749 Paper 2 Preliminary Examination For Examiner’s Use (b) After overtaking car A, car B is traveling at a speed of 11.5 m s–1 just before it falls off a cliff of height 6.5 m. The effect of air resistance is negligible. (i) Determine the angle θ car B makes with the horizontal just before it hits the ground. θ = ………………………… ° [2] (ii) Car A subsequently falls off the same cliff as car B. State and explain how the angle it makes with the horizontal will differ, if any, with that of car B found in (b)(i). …………………………………………………………….………………………… ………………………………………………………………..……..……………… …………………………………………………………..……..…………………… ……………………………………………………….....………..………………… ………………………………………………………………..……….……...… [2] [Total: 8]

8 Anglo-Chinese Junior College 2023 J2 H2 9749 Paper 2 Preliminary Examination For Examiner’s Use 3 (a) Explain what is meant by upthrust. ……………………………..……………………………………………………………. ……………………………..……………………………………………………………. .………………………………………………………..……………………………... [1] (b) Weather balloons are an important tool for meteorologists. They provide data that is used to improve weather forecasts and to understand the atmosphere. Fig. 3.1 shows a helium inflated weather balloon tethered to the ground by a rope. The balloon is spherical in shape and has a diameter of 1.5 m. Fig. 3.1 (i) On Fig. 3.1, draw and label the forces acting on the balloon. [2] (ii) The density of the air surrounding the balloon is 1.3 kg m –3. The mass of the helium filled balloon is 300 g. Determine the tension of the rope. tension = ………………………… N [2] (c) The rope is cut and the balloon rise to an equilibrium altitude of up to 30 km.

9 [Turn over Anglo-Chinese Junior College 2023 J2 H2 9749 Paper 2 Preliminary Examination For Examiner’s Use Explain how the balloon rises and reaches this height. ……………………………………………………………………..…………………… ……………………………………………………………………..…………………… ……………………………………………………………………..…………………… ……………………………………………………………………..…………………… ……………………………………………………………………..…………………… ……………………………………………………………………………..…………… …………………………………………………………………………………….……[3] [Total: 8]

10 Anglo-Chinese Junior College 2023 J2 H2 9749 Paper 2 Preliminary Examination For Examiner’s Use 4 (a) Using energy considerations, distinguish between electromotive force (e.m.f.) and potential difference (p.d.). ……………………………………………..……………………………………………… ……………………………………………………..……………………………………… ……………………………………………..……………………………………………… ……………………………………………………..…………………………