2019 RI Prelims Paper 2 QP

This document consists of 18 printed pages. © Raffles Institution [Turn over   Centre Number Index Number Name Class S3016 RAFFLES INSTITUTION 2019 Preliminary Examination PHYSICS Higher 2 Paper 2 Structured Questions 9749/02 18 September 2019 2 hours Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your index number, name and class in the spaces at the top of this page. Write in dark blue or black pen in the spaces provided in this booklet. You may use a 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. Answer all questions. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use 1 / 10 2 / 12 3 / 8 4 / 10 5 / 10 6 / 10 7 / 20 Deduction Total / 80

2   © Raffles Institution   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 × 10 23 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  21 2ut at 2v  2 2ua s work done on/by a gas W  p V hydrostatic pressure p  ρgh gravitational potential   Gm r temperature T/K  / C 273.15T  pressure of an ideal gas p  21 3 Nm cV mean translational kinetic energy of an ideal gas molecule E  3 2 kT   displacement of particle in s.h.m. x  0 sinx t velocity of particle in s.h.m. v  0 cosvt  22 0x x  electric current I   Anvq resistors in series R  12 ...RR resistors in parallel 1/ R  121 1 ...RR electric potential V  4 Q r alternating current/voltage x  0 sinx 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  0n I radioactive decay x   0 expxt  decay constant   1 2 ln2 t

3   © Raffles Institution [Turn over   Answer all the questions in the spaces provided. 1 (a) Explain why it is technically incorrect to define speed as “distance travelled per second”. Include in your answer the correct definition of speed. [2] (b) A baseball player throws a ball with an initial speed of 15 m s 1 at an angle  above the horizontal, at a height 2.0 m above the ground. At the maximum height above the ground, the speed of the ball is 7.5 m s1. Ne glecting air resistance, determine (i) the angle ,  = ° [1] (ii) the time of flight tf. t f = s [3]

4   © Raffles Institution   (c) (i) On Fig. 1.1, sketch the variation with time t of the vertical component of velocity vy of the ball and label it Q. Mark on the horizontal axis the instant t1 at which the ball reaches its maximum height. [1] (ii) If air resistance is not negligible, on Fig. 1.1, sketch the variation with t of v y for the entire flight and label it R. [3]    vy / m s1  t / s Fig. 1.1 tf 0

5   © Raffles Institution [Turn over   2 A theme park ride is illustrated in Fig. 2.1. The carriage of mass 450 kg, moving at 1.0 m s 1, slides down the slope and then moves over a small hill. The slope consists of two circular arcs of the same radius 15 m and the hill has a small circular arc of radius 20 m at the top. Assume no resistive force acts on the carriage. Fi g. 2.1 (not to scale) (a) Show that h is 7.0 m. [1] (b) Calculate the speed of the carriage when it reaches point A. speed of the carriage at point A = m s 1 [2] (c) On Fig. 2.2, draw and label the forces acting on the carriage when it is at A. Fig. 2.2 [2] h 40° 40° circular arc of radius 15 m circular arc of radius 15 m small circular arc of radius 20 m A 1.0 m s1 3.5 m small circular arc of radius 20 m small circular arc of radius 20 m

6   © Raffles Institution   (d) Calculate the normal contact force acting on the carriage at A. normal contact force on carria ge at A = N [2] (e) During the entire journey, the carriage experiences varying normal contact force. (i) On Fig. 2.1, mark with an “X” the point at which the carriage experiences the largest normal contact force. [1] (ii) Explain your answer in (e)(i). [2] (f) Determine the maximum speed of the carriage at A such that the carriage does not lose contact with the track. maximum speed of the carriage = m s 1 [2]

7   © Raffles Institution [Turn over   3 (a) Distinguish between longitudinal waves and transverse waves. [2] (b) State a phenomenon associated with transverse waves that is not observed with longitudinal waves. [1] (c) A point source of sound radiates energy uniformly in all directions. At a particular frequency, the intensity of sound 1.5 m away from the source is 1.2  105 W m2, corresponding to an amplitude of oscillation of the air molecules of 84 m. A microphone with a receiving area of 1.3  103 m2 is placed 6.0 m away from the source. Assuming that the sound is propagated without energy loss, determine (i) the intensity of the sound at the microphone, intensity = W m 2 [2] (ii) the power of the sound incident on the microphone, power = W [1] (iii) the amplitude of vibration of the air molecules at the microphone. amplitude = m [2]

8   © Raffles Institution   4 (a) Define electric field strength at a point. [2] (b) Two charged metal spheres A and B, each of di ameter 0.16 m, are isolated in space as shown in Fig. 4.1. Fig. 4.1 (not to scale) The centres of the spheres are separated by a distance of 60 m. Point P is at the mid-point along the line joining the centres of the two spheres. Each sphere carries a charge of 0.040 nC. (i) In Fig. 4.2, sketch the pattern of elec tric field lines in the region surrounding the spheres. Fi g. 4.2 (not to scale) [2] sphere A sphere B P 60 m P sphere A sphere B X 14 m

9   © Raffles Institution [Turn over   (ii) Determine the magnitude and direction of the electric field strength at point X, 14 m from the surface of sphere A along the line joining the centres of the spheres. magnitude of electric field strength = N C 1 direction of electric field strength = [3] (c) (i) Calculate the potential at point P. potential = V [1] (ii) Hence or otherwise, without further calculat ion, sketch on Fig. 4.3 a graph to show the variation with displacement x along the line of centres, of potential V between the centres of the spheres.