RVHS 2022 Prelim P2

River Valley High School Page 1 of 22 H2 Physics 9749 2022 JC 2 Preliminary Examinations RIVER VALLEY HIGH SCHOOL JC 2 PRELIMINARY EXAMINATIONS H2 PHYSICS 9749 / 2 PAPER 2 12 SEPTEMBER 2022 2 HOURS CANDIDATE NAME CENTRE NUMBER S INDEX NUMBER CLASS 2 1 J INSTRUCTIONS TO CANDIDATES DO NOT OPEN THIS BOOKLET UNTIL YOU ARE TOLD TO DO SO. Read these notes carefully. Write your name, centre number, index number and class in the spaces at the top of this page and on all work you hand in. Write in dark blue or black pen on both sides of the paper. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. The use of an approved scientific calculator is expected where appropriate. Candidates answer on the Question Paper. No Additional Materials are required. Answer all questions. The number of marks is given in brackets [ ] at the end of each question or part question. FOR EXAMINERS’ USE Paper 2 1 / 5 2 / 7 3 / 10 4 / 6 5 / 12 6 / 8 7 / 12 8 / 20 Deduction Paper 2 / 80 This document consists of 22 printed pages.

River Valley High School Page 2 of 22 H2 Physics 9749 2022 JC 2 Preliminary Examinations Data speed of light in free space, c = 3.00  108 m s–1 permeability of free space, 0 = 4   10–7 H m–1 permittivity of free space, 0 = 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

River Valley High School Page 3 of 22 H2 Physics 9749 2022 JC 2 Preliminary Examinations Formulae uniformly accelerated motion 2 2 1 atuts += 22 2v u as=+ work done on / by a gas W p V= hydrostatic pressure p gh= gravitational potential  = − GM / r temperature T / K = T / C + 273.15 pressure of an ideal gas = 2 3 1 cV Nmp mean translational kinetic energy of an ideal gas molecule kTE 2 3= displacement of particle in s.h.m., x = x0 sin t velocity of particle in s.h.m., v = v0 cos t = )( 22 0 xx − electric current, I = Anvq resistors in series, 12R R R= + + resistors in parallel, 121/ 1/ 1/R R R= + + electric potential, r QV 04= alternating current/voltage, x = x0 sin t magnetic flux density due to a long straight wire, dB   2 0I= magnetic flux density due to a flat circular coil, r NB 2 0 I= magnetic flux density due to a long solenoid, InB 0= radioactive decay, x = x0 exp (−t) decay constant, 2 1 2ln t=

River Valley High School Page 4 of 22 H2 Physics 9749 2022 JC 2 Preliminary Examinations Answer all the questions in the space provided. 1 (a) State what is meant by a random error? …………..…….…………………………………………………………………............. ……………………………………………………………………………………… [1] (b) A ship at sea is travelling with a velocity of 13 m s–1 in a direction 35° east of north in still water, as shown in Fig. 1.1. Fig. 1.1 (i) Calculate the north component of the ship’s velocity. north component of velocity = ........................ m s−1 [1] (ii) The ship’s velocity is measured with an uncertainty of ± 10 %. Its direction is measured with an uncertainty of ± 1o. Determine the north component of the velocity with its associated uncertainty. north component of velocity = ........................ ± .............. m s−1 [3] velocity 13 m s−1 N 35o

River Valley High School Page 5 of 22 H2 Physics 9749 2022 JC 2 Preliminary Examinations 2 (a) Explain what is meant by a system is in equilibrium. …………..…….…………………………………………………………………............. …………..…….…………………………………………………………………............. ……………………………………………………………………………………… [2] (b) In a children’s game, small balls are thrown at wood blocks in order to turn them over. One such block, of mass 300 g, with each side of length 10 cm, is shown in Fig. 2.1 below. Fig. 2.1 Fig. 2.2 In order to turn the block over, the centre of gravity C must be raised such that that C is vertically above the corner A, as shown in Fig. 2.2. Fig. 2.3 The block is struck by a ball of mass 15 g travelling horizontally 1.0 cm below the top surface of the block as shown in Fig. 2.3. The collision is perfectly elastic and, without sliding, the block turns about the corner A. (i) Label on Fig. 2.3, the forces acting on the block when the ball just hits the block causing it to turn about corner A. [2] 10 cm 10 cm

River Valley High School Page 6 of 22 H2 Physics 9749 2022 JC 2 Preliminary Examinations (ii) Hence or otherwise, determine the minimum force needed for ball to act on the block in order for the block to turn about A. force = ........................ N [3] 3 Fig. 3.1 shows a frictionless piston-cylinder with a built-in heater. Fig. 3.1 Before the heater is switched on, the cylinder contains 0.60 m3 of helium gas at pressure 101 kPa and temperature of 28 oC. When the heater is switched on for 15 minutes, the gas expands at constant pressure and its temperature rises to 57 oC. A heat loss of 7000 J to the surrounding occurs during the process. Assume the gas behaves like an ideal gas and the heater is rated at 24 W and 120 V. (a) (i) Using the kinetic theory of gases, explain why the volume of the gas expands when it is heated at constant pressure. ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ............................................................................................................... [2] heater helium gas piston cylinder

River Valley High School Page 7 of 22 H2 Physics 9749 2022 JC 2 Preliminary Examinations (ii) On Fig. 3.2, sketch the pressure -volume graph for the process. Label the graph with appropriate values of pressure and volume. Fig. 3.2 [2] (iii) Using first law of thermodynamics, determine the change in internal energy of the helium gas. change in internal energy = ........................ J [3] pressure / kPa volume / m3

River Valley High School Page 8 of 22 H2 Physics 9749 2022 JC 2 Preliminary Examinations (b) The thermodynamic temperature of a gas T is a measure of the average translational kinetic energy of a molecule in the gas. The pressure p of an ideal gas is related to its microscopic quantities by the relationship pV = 21 3 Nm c where V : volume occupied by the gas N : total number of gas molecues m : mass of each gas molecule 2c : mean square speed of the gas molecules. (i) By comparing the above relationship with pV = Nkt, where k is the Boltzmann constant, show that the average kinetic energy of the molecules is 3 2E kT= .