2021 RI Promo Sect C QP

© Raffles Institution 9749   Name: ( ) CT Group: 22S0 RAFFLES INSTITUTION 2021 YEAR 5 PROMOTIONAL EXAMINATION 30 September 2021 H2 PHYSICS RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFL ES 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 INSTITUTION RAFFLES INSTITUTION RAFFL ES 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 INSTITUTION RAFFLES INSTITUTION RAFFL ES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES Section C INSTRUCTIONS TO CANDIDATES Write your name, index number and CT Group. Write your answers to Section C in the spaces provided on the question paper. For Examiner’s Use Section C 6 / 15 7 / 15 This document consists of 10 printed pages.

2 © Raffles Institution 9749 [Turn over     Section C (30 marks) 6 (a) (i) Define gravitational potential at a point. [1] (ii) Explain why gravitational potential in a gravitational field is negative. [2] (b) The variation with distance r of the gravitational potential  from the centre of a planet is shown in Fig. 6.1. Fig. 6.1 r / 108 m / 108 J kg–1 -10.0 -8.0 -6.0 -4.0 -2.0 0.0 0.0 2.0 4.0 6.0 8.0 10.0 12.0

3 © Raffles Institution 9749 [Turn over     (i) Using Fig. 6.1, show that the mass of the planet is 271.9 10 kg . [1] (ii) Fig. 6.2 shows the planet and two points, X and Y, in its gravitational field. Points X and Y are 88.0 10 m and 82.0 10 m from the centre of the planet respectively. Fig. 6.2 1. Determine the orbital speed of an object that is orbiting the planet with a radius of 82.0 10 m . Explain your working. orbital speed = 1m s [3] X Y planet

4 © Raffles Institution 9749 [Turn over     2. As a space stone approaches the planet, it passes through point X with a speed of 413.5 10 m s  and continues to pass through point Y. The direction in which the space stone passes through point Y is parallel to a tangent to the planet’s surface as shown in Fig. 6.3.