2021 H2 Phy Prelim Paper 2 Question Paper (forJCs)

©YIJC [Turn over YISHUN INNOVA JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME CG INDEX NO PHYSICS Paper 2 Structured Questions Candidates answer on the Question Paper. No Additional Materials are required. 9749/02 1 September 2021 2 hours READ THESE INSTRUCTIONS FIRST This document consists of 21 printed pages and 3 blank pages. For Examiner’s Use Paper 2 1 /8 2 /8 3 /5 4 /6 5 /11 6 /8 7 /11 8 /23 Penalty Paper 2 Total /80 Write your name and class 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 or graphs. Do not use staples, paper clips, highlighters, glue or correction fluid/tape. 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.

2 ©YIJC 9749/02/YIJC/PRELIM/21 [Turn over 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 Formulae uniformly accelerated motion, s = ut + 2 1 at2 v2 = u2 + 2as work done on/by a gas, W = p  V hydrostatic pressure, p =  g h gravitational potential,  = r Gm temperature, T/K = T/°C + 273.15 pressure of an ideal gas, p = 2CV Nm 3 1 mean translational kinetic energy of an ideal gas molecule, E = kT2 3 displacement of particle in s.h.m. x = xo sin  t velocity of particle in s.h.m., v = vo cos  t =   )( 22 xxo  electric current, I = A n v q resistors in series, R = R1 + R2+………. resistors in parallel, R 1 = ........11 21  RR electric potential, V = r Q o4 alternating current/voltage, x = xo sin  t magnetic flux density due to a long straight wire, B = dπ2 o Iμ magnetic flux density due to a flat circular coil, B = r2 No Iμ magnetic flux density due to a long solenoid, B = Ion radioactive decay, x = xo exp(–t) decay constant,  = 2 1t 2 ln

3 ©YIJC 9749/02/YIJC/PRELIM/21 [Turn over Answer all the questions in the spaces provided. 1 (a) State the principle of conservation of linear momentum. ……………………………………………………………………………………………………. ……………………………………………………………………………………………………. ……………………………………………………………………………………………………. …………………………………………………………………………………………….. [2] (b) Two microscopic particles are travelling along the same straight line in the same direction, as shown in Fig. 1.1. Particle X has mass 4.00 u and horizontal velocity 500 m s –1 whereas particle Y has mass 28.0 u and horizontal velocity 340 m s–1. After the two particles collide , X has a horizontal velocity of 220 m s –1 in the same direction as before and Y has horizontal velocity v. (i) Determine the magnitude of velocity v. v = ……………….. m s–1 [2] (ii) Deduce whether the above collision is elastic or not. Show your workings clearly. ……………………………………………………………………………………………... ……………………………………………………………………………………… [2] 4.00 u 500 m s–1 340 m s–1 X 28.0 u Y Fig. 1.1

4 ©YIJC 9749/02/YIJC/PRELIM/21 [Turn over (iii) Use Newton’s third law to explain why, during the collision, the change in momentum of X is equal and opposite to the change in momentum of Y. ……………………………………………………………………………………………... ……………………………………………………………………………………………... ……………………………………………………………………………………………... ……………………………………………………………………………………………... ……………………………………………………………………………………… [2] [Total: 8]

5 ©YIJC 9749/02/YIJC/PRELIM/21 [Turn over centre of circle 2 Fig. 2.1 shows a cross-sectional view of a Formula 1 racing car travelling on a rough track that is banked such that it makes an angle of 30 with the horizontal. At a certain bend along the track, the radius of curvature is 50.0 m. The mass of the car is 1000 kg. Fig. 2.1 (a) Explain briefly how the banked track assists the car in travelling round the bend. ……………………………………………………………………………………………………. ……………………………………………………………………………………………………. ……………………………………………………………………………………………………. …………………………………………………………………………………………….. [2] (b) The driver tries to negotiate the bend at its maximum speed without slipping. (i) In Fig. 2.1, draw a free-body diagram of the forces acting on the car. [3] (ii) Given that t he maximum frictional force between the wheels of the car and the track is 6000 N, calculate this maximum speed. maximum speed = ………………….. m s1 [3] [Total: 8] 50.0 m 30

6 ©YIJC 9749/02/YIJC/PRELIM/21 [Turn over 3 (a) Explain why the internal energy of a fixed amount of real gas is NOT solely dependent on its thermodynamic temperature. ……………………………………………………………………………………………………. ……………………………………………………………………………………………………. …………………………………………………………………………………………….. [2] (b) The pressure of an ideal gas, p, is related to its density, , by the equation 2 3 1 cp  where 2c is the mean square speed of the gas molecules. Using the above equation, show that the internal energy of a fixed amount of ideal gas is directly proportional to its thermodynamic temperature. [3] [Total: 5]

7 ©YIJC 9749/02/YIJC/PRELIM/21 [Turn over 4 A cylinder of constant volume 3.8  104 cm3 contains an ideal gas at pressure 2.5  105 Pa and temperature 181 °C. The gas is heated with 2700 J of t he thermal energy. The final temperature and pressure of the gas are T and p. (a) Calculate (i) the number of molecules N in the cylinder, N = ………………….. [2] (ii) the change in internal energy of the ideal gas. Explain your working. change in internal energy = ………………….. J [2] (b) Use your answer in (a) to determine the final temperature T, in Kelvin, of the gas in the cylinder. T = ………………….. K [2] [Total: 6]

8 ©YIJC 9749/02/YIJC/PRELIM/21 [Turn over 5 (a) A metal wire in a circuit has a damaged part. The resistivity of the metal is unchanged but the cross-sectional area of the wire is reduced over a 4.0 mm length, as shown in Fig. 5.1. Fig. 5.1 The wire has diameter d at cross-section X and diameter 0.72 d at cross-section Y. The current in the wire is 0.50 A. (i) Determine the ratio of average drift speed of electrons at cross-section Y average drift speed of electrons at cross-section X . ratio = ……………………. [2] (ii) If the resistivity of the material of the wire is 1.12  106  m and d = 0.21 mm, determine the resistance of the damaged length. resistance = …………………….  [2] (iii) When current flows through the wire, explain why the damaged part of the wire has a higher voltage per unit length as compared to the rest of the wire. ……………………………………………………………………………………………... ……………………………………………………………………………………………... ……………………………………………………………………………………………... ……………………………………………………………………………………… [1] 0.72 d 4.0 mm

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