2020 ASRJC H1 Physics Prelims P2 Questions

1 8867/02/ASRJC/2020Prelim [Turn Over Name: _____________________________ ( ) Class: 20 / ______ 2020 JC2 Preliminary Examination PHYSICS Higher 1 8867/02 Paper 2 Structured Questions Thursday 17 September 2020 2 hours Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, class index number and class in the spaces provided above. Write in dark blue or black pen on both sides of the paper. You may use an HB pencil for any diagrams or graphs. The use of an approved scientific calculator is expected, where appropriate. Section A Answer all questions. Section B 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. This document consists of 19 printed pages and 1 blank page. For Examiner’s Use Paper 1 (30 marks) Paper 2 (80 marks) 1 /10 2 / 8 3 / 5 4 / 7 5 /14 6 /16 7 /20 deductions Paper 2 Total (80 m) ANDERSON SERANGOON JUNIOR COLLEGE

2 8867/02/ASRJC/2020Prelim Data speed of light in free space, c = 3.00 × 108 m s−1 elementary charge, e = 1.60 × 10−19 C 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 the Avogadro constant NA = 6.02 × 1023 mol−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 + 1 2 at 2 v2 = u2 + 2as resistors in series, R = R1 + R2 + … resistors in parallel, 1/R = 1/R1 + 1/R2 + …

3 8867/02/ASRJC/2020Prelim [Turn Over Section A Answer all the questions in this section. 1 (a) A marble is projected up a smooth ramp with an initial speed of 2.0 m s−1. The ramp makes an angle of 30° with the ground and the height of the ramp is 0.13 m as shown in Fig. 1.1. Fig. 1.1 (not to scale) The marble then leaves the ramp and first hits the ground at a distance d from the edge of the ramp. (i) By using energy consideration or otherwise, show that the speed of the marble when it reaches the top of the ramp is 1.2 m s−1. [2] (ii) Hence, calculate the distance d. d = ……………………………. m [2] 0.13 m 2.0 m s−1 ramp ground marble path of marble d 30°

4 8867/02/ASRJC/2020Prelim (b) Along a horizontal frictionless surface, ball A moves with speed v towards a stationary ball B as shown in Fig. 1.2. Ball A has mass 4.0 kg and ball B has mass 12 kg. The balls collide and then move apart as shown in Fig. 1.3. Ball A has velocity 6.0 m s−1 at an angle of  to the direction of its initial path. Ball B has velocity 3.5 m s−1 at an angle of 30° to the direction of the initial path of ball A. (i) By considering the components of momentum at right−angles to the direction of the initial path of ball A, show that  is 61°. [2] (ii) Hence, determine the initial speed v of ball A. v = ……………………………. m s−1 [2] (iii) By calculation of kinetic energies, state and explain whether the collision is elastic or inelastic. ……………………………………………………………………………………………….. ……………………………………………………………………………….………….... [2] [total: 10] Fig. 1.2 Fig. 1.3

5 8867/02/ASRJC/2020Prelim [Turn Over 2 (a) A climber rests against a vertical wall supported by a light rope with one end fixed to a point P on the wall, as shown in Fig. 2.1. Fig. 2.1 The weight W of the climber is 520 N. The rope makes an angle of 18° to the vertical and has a tension T. The contact force R on the climber at the wall is at an angle 25° from the horizontal. (i) Complete Fig. 2.2 by drawing a labelled vector triangle to represent the forces acting on the climber. Fig. 2.2 [2] wall P T W R 25° 18° W

6 8867/02/ASRJC/2020Prelim (ii) Hence, or otherwise, calculate the tension T. T = ……………………………. N [2] (b) An oil drop of mass 2.6 × 10−14 kg has a charge equivalent to that of 8 electrons. It remains stationary between two metal plates A and B at different electric potentials, as shown in Fig. 2.3. Fig. 2.3 (i) State and explain which plate is at higher electric potential. ………………………………………………………………………………………………. ………………………………………………………………………………………………. ………………………………………………………………………………………………. …………………………………………………………………………………………….[2] (ii) Determine magnitude of the electric field strength between the plates. electric field strength = ……………………………. N C−1 [2] [total: 8] oil droplet metal plate A metal plate B

7 8867/02/ASRJC/2020Prelim [Turn Over 3 A 2.0 kg mass sits on a light platform supported by a spring of force constant 1400 N m−1 within a column, as shown in Fig. 3.1. A force is exerted on the mass causing a total compression of 10 cm of the spring. Fig. 3.1 (a) Calculate the elastic potential energy stored in the spring. elastic potential energy = ……………………………. J [1] (b) The force is then removed and the mass moves up the column, comes to an instantaneous rest within the column before falling back onto the platform. The mass experiences an average frictional force of 3.0 N as it moves up the column. (i) Determine the maximum height h0 reached by the mass measured from its point of released. h0 = ……………………………. m [2] spring platform 2.0 kg mass column fixed support

8 8867/02/ASRJC/2020Prelim (ii) Explain whether the compression in the spring will be 10 cm when the mass next comes to a stop after falling back onto the platform , assuming that there is no loss in mechanical energy when the mass collides with the platform. ………………………………………………………………………………….................... ………………………………………………………………………………….................... ………………………………………………………………………………….................... ……………………………………………………………………………….………….....[2] [Total: 5] 4 (a) Explain, using Newton’s law of motion, why a body travelling in a circle with constant speed will experience a force. …………………………………………………………………………………............................. …………………………………………………………………………………............................. …………………………………………………………………………………............................. ……………………………………………………………………………….…………..............[2] (b) Fig. 4.1 shows a merry-go-round, a ride consisting of a circular rotating platform found in playgrounds. Fig. 4.1 centre of rotation circular rotating platform railing

9 8867/02/ASRJC/2020Prelim [Turn Over At a particular playground, some children sit at different distances from the centre of the merry-go-round of diameter 6.5 m as shown in Fig. 4.2. The merry-go-round turns 5.5 revolutions per minute. Fig. 4.2 (i) Explain whether all the children have the same linear speed. ………………………………………………………………………………........................ ………………………………………………….……………………………....................... …………………………………………………………………………………..................... …………………………………………………………………………………….............[2] (ii) Calculate the angular speed of the merry-go-round. angular