2021 Prelim Phy P2

Name : Centre/Index Number: Class: DUNMAN HIGH SCHOOL Preliminary Examination Year 6 H2 PHYSICS Paper 2 Structured Questions Candidates answer on the Question Paper 9749/02 17 September 2021 2 hours READ THESE INSTRUCTIONS FIRST Write your centre number, index number, name and class at the top of this page. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Answer all questions in the spaces provided on the question paper. The use of an approved scientific calculator is expected, where appropriate. You may lose marks if you do not show your working or if you do not use appropriate units. The number of marks is given in brackets [ ] at the end of each question or part question. © DHS 2021 9749/02 [Turn over This document consists of 25 printed pages and 1 blank page.This document consists of 21 printed pages and 1 blank page. For Examiner’s Use 1 9 2 9 3 9 4 7 5 10 6 11 7 9 8 16 Total 80

2 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 © DHS 2021 9749/02

3 Formulae uniformly accelerated motion, s = ut + 1 2 at2 v2 = u2 + 2as work done on/by a gas, W = pV hydrostatic pressure, p = gh gravitational potential,  = −Gm/r temperature, T/K = T/oC + 273.15 pressure of an ideal gas, p = 21 3 Nm cV   mean translational kinetic energy of an ideal gas molecule, E = kT2 3 displacement of particle in s.h.m., x = x0 sin t velocity of particle in s.h.m., v = v0 cos t =  22 xxo  electric current, I = Anvq resistors in series, R = R1 + R2 + . . . resistors in parallel, 1/R = 1/R1 + 1/R2 + . . . electric potential, V = r Q o4 alternating current / voltage, x = x0 sin t magnetic flux density due to a long straight wire, B = 0 2 d I  magnetic flux density due to a flat circular coil, B = 0 2 N r I magnetic flux density due to a long solenoid, B = 0nI radioactive decay, x = x0 exp(t) decay constant,  = 1 2 ln2 t © DHS 2021 9749/02 [Turn over

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5 Answer all questions in the spaces provided. 1 (a) Length, mass and temperature are all SI base quantities. State two other SI base quantities. 1. ………………………………………….……………………………………………………. 2. ……………………………………………………………….…………………………… [2] (b) A small frictionless trolley of mass m is attached to a fixed point A by means of a spring, as shown in Fig. 1.1. Fig. 1.1 The trolley is then displaced horizontally 5.0 cm and released. The period T of the oscillations of the trolley is given by where k is the spring constant of the spring. Data for the oscillation is shown in Fig. 1.2. Fig. 1.2 © DHS 2021 9749/02 [Turn over trolley A quantity magnitude uncertainty k / N m-1 25 ± 8 % m / kg 200 × 10–3 ± 2 %

6 (i) Determine the period T of the oscillations, with its uncertainty. Give your answer to an appropriate number of significant figures. T = ........................... ± ........................... s [4] (ii) 1. Derive an expression for total energy of the trolley in terms of T. [2] 2. Calculate the total energy of the trolley using the period calculated in b(i). total energy = ……………………J [1] © DHS 2021 9749/02

7 2 (a) State the principle of conservation of momentum. ………………………………………………………………………..……………………………... ………………………………………………………………………………………..……………... ………………………………………………………….……………………………………….. [2] (b) Two blocks, A and B, are on a horizontal frictionless surface. The blocks are joined together by a spring, as shown in Fig. 2.1. Block A has mass 4.0 kg and block B has mass 6.0 kg. The two blocks are held apart so that the spring has an extension of 8.0 cm.The elastic potential energy of the spring at an extension of 8.0 cm is 0.48 J. The blocks are released from rest at the same instant. When the extension of the spring becomes zero, block A has speed vA and block B has speed vB. For the instant when the extension of the spring becomes zero, (i) use the conservation of momentum to show that [3] (ii) use the information in (b)(i) to determine the kinetic energy of block A. It may be assumed that the spring has negligible kinetic energy and that air resistance is negligible. © DHS 2021 9749/02 [Turn over Fig. 2.1 block A mass 4.0 kg block B mass 6.0 kgsprin g horizontal frictionless surface

8 kinetic energy of block A = ……………………J [2] (iii) The blocks are released at time = 0. On Fig. 2.2, sketch a graph to show the variation with time of the momentum of block A, until the extension of the spring becomes zero. Numerical values of momentum and time are not required. [2] 3 (a) A block of mass 0.40 kg slides in a straight line with a constant speed of 0.30 m s −1 along a horizontal surface, as shown in Fig. 3.1. © DHS 2021 9749/02 Fig. 2.2 time momentum 0 0 spring 0.30 m s-1block of mass 0.40 kg

9 The block hits a spring and decelerates. The speed of the block becomes zero when the spring is compressed by 8.0 cm. (i) Calculate the initial kinetic energy of the block. kinetic energy = ……………………J [1] (ii) The variation of the compression x of the spring with the force F applied to the spring is shown in Fig. 3.2. Use your answer in (a)(i) to determine the maximum force FMAX exerted on the spring by the block. Explain your working. © DHS 2021 9749/02 [Turn over Fig. 3.1 x / cm 8.0 0 0 F FMAX Fig. 3.2

10 FMAX = ……………………N [3] (iii) Calculate the maximum deceleration of the block. deceleration = ……………………m s-2 [1] (iv) State and explain whether the block is in equilibrium 1. before it hits the spring, ………………………………………………………………………. ………………....... ........................................................................................................................... [1] 2. when its speed becomes zero. ……………………………………………………………………………...................... ........................................................................................................................... [1] (b) The mass m of the block in (a) is now varied. The initial speed of the block remains constant and the spring continues to obey Hooke’s law. On Fig. 3.3, sketch the variation of the maximum compression x0 of the spring with the mass m. [2] 4 (a) Sketch, on Fig. 4.1, a standing wave with 4 antinodes only. © DHS 2021 9749/02 x0 0 0 m Fig. 3.3