2022 RI Yr 5 CT Sect B QP

© Raffles Institution [Turn over Name: ( ) CT Group: 23S0 RAFFLES INSTITUTION 2022 YEAR 5 JULY COMMON TEST H2 PHYSICS RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFL ES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITU TION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFL ES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES I NSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFL ES INSTITUTION I Section B INSTRUCTIONS TO CANDIDATES Write your name, index number and CT Group. Write your answers to Section B in the spaces provided in this booklet. For Examiner’s Use Section A MCQ / 15 Section B 16 / 9 17 / 10 18 / 10 19 / 10 20 / 10 21 / 11 22 / 20 Deductions Total / 95 There are 18 printed pages, inclusive of the cover page, in this booklet.

2 © Raffles Institution 16 Drag coefficient is a quantity used to quantify the drag force acting on an object in a fluid environment. A smaller drag coefficient indicates that an object has less aerodynamic drag. The drag coefficient Cd of a steel ball of diameter d and mass m when it falls through a fluid of density ρ at terminal speed v is given by the expression 22 8 d mgC vdπρ= where g is the acceleration of free fall. (a) Determine the SI base units of Cd. SI base units of Cd = [2] (b) In an experiment to determine the drag coefficient of a steel ball falling through air, the following measurements are made: d = (9.6 ± 0.1) mm m = (3.64 ± 0.01) g g = (9.81 ± 0.03) m s−2 ρair = (1.23 ± 0.02) kg m−3 v = (39.8 ± 0.1) m s−1 (i) State the instrument that was used to measure d. [1] (ii) Determine Cd, with its actual uncertainty. Give your answer to an appropriate number of significant figures. Cd = ± [4]

3 © Raffles Institution [Turn over (iii) Suggest two methods to reduce the uncertainty in the measurement of the diameter of the steel ball. 1 2 [2]

4 © Raffles Institution 17 In an attempt to chase his enemy, Captain America rides his motorbike up a ramp inclined at an angle of 30° to jump over 14 identical crates of length 1.5 m and height 1.5 m as shown in Fig. 17.1. The motorbike leaves the ramp at a speed of 15 m s−1. (a) Determine the horizontal and vertical components of the initial velocity of the motorbike. horizontal component of initial velocity = m s−1 vertical component of initial velocity = m s−1 [2] (b) Show that the motorbike will be able to go over all the 14 crates without hitting the crates. [3] Fig. 17.1 30° 2.5 m 1.5 m 1.5 m ground 15 m s−1 …… 14 crates

5 © Raffles Institution [Turn over (c) Determine the velocity of the motorbike just before it lands on the ground. magnitude of velocity = m s−1 direction of velocity = [3] (d) In another chase, Captain America rides his motorbike up another ramp that is inclined at a greater angle of 35° as shown in Fig. 17. 2. He leaves the ramp with a velocity that has the same horizontal component as calculated in (a). Without any calculation, state and explain whether the horizontal displacement of the motorbike when it lands on the ground is greater than, smaller than or equal to that of the first chase. [2] Fig. 17.2 35° 2.5 m 1.5 m 1.5 m ground …… 14 crates

6 © Raffles Institution 18 A metal sphere A of mass 0.050 kg is suspended from a fixed point. It is pulled aside and released so that it swings and collides head- on with another identical metal sphere B at its lowest point as shown in Fig. 18.1. (a) Identify the external forces acting on the system of the two spheres during their collision. You may ignore air resistance. [1] (b) Explain why, despite the presence of external forces, the principle of conservation of momentum may still be applied to determine the speeds of the two spheres immediately after the collision. [2] Fig. 18.1 A B

7 © Raffles Institution [Turn over (c) The variation with time t of the force exerted by sphere A on sphere B during the collision is shown in Fig. 18.2. Estimate the impulse exerted by sphere A on sphere B during the collision. impulse = N s [2] force / N t / s 0 15.0 0.01 0.02 0.03 10.0 5.0 0 Fig. 18.2

8 © Raffles Institution (d) The velocity of sphere A just before collision is 4.0 m s−1. Determine the speeds of the two spheres immediately after the collision. speed of sphere A = m s−1 speed of sphere B = m s−1 [2] (e) (i) With reference to Fig. 18.2, state the value of t during the collision at which the two spheres move with a common speed. t = s [1] (ii) Determine the value of this common speed. common speed = m s−1 [2]

9 © Raffles Institution [Turn over 19 Fig. 19.1 shows a window panel that is hinged at its top end to a wall and supported by a rod. The window panel of weight 240 N is at an angle of 30° to the vertical. The rod exerts a force of 80 N perpendicular to the window panel at a distance of 150 cm from the hinge. (a) Explain two conditions required for the window panel to be in a state of equilibrium. 1 2 [2] (b) State what is meant by the centre of gravity of the window panel. [1] (c) Use the principle of moments to determine the distance between the centre of gravity of the window panel and the hinge. distance = cm [2] window panel wall 80 N hinge 30° Fig. 19.1 240 N rod

10 © Raffles Institution (d) On Fig. 19.1, draw an arrow to indicate the direction of the force on the window panel at the hinge. [2] (e) Determine the magnitude of the force acting on the window panel at the hinge. magnitude of force = N [3]