2021 RI Promo Sect B 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 B INSTRUCTIONS TO CANDIDATES Write your name, index number and CT Group. Write your answers to Section B in the spaces provided on the question paper. For Examiner’s Use Section A MCQ / 15 Section B 1 / 10 2 / 10 3 / 10 4 / 8 5 / 12 Section C 6 / 15 7 / 15 Deductions Total / 95 % This document consists of 12 printed pages.

2 © Raffles Institution 9749 [Turn over     Section B (50 marks) 1 A sphere of mass 0.040 kg and density 38910 kg m is suspended by a thin string and submerged in a tall container of liquid of density 3 k11 0 g m4  as shown in Fig. 1.1. Fig. 1.1 The string is cut and the sphere begins falling from rest through the liquid, where it experiences a drag force F D such that DFv  where v is the speed of the sphere and  is a constant with a value of 10.26 kg s . After falling for 2.0 s, the sphere reaches terminal velocity. The sphere then continues to fall at terminal velocity for another 2.5 s. (a) (i) Show that the upthrust on the sphere is 0.062 N. [1] (ii) Determine the terminal velocity of the sphere. terminal velocit y = m s –1 [2] sphere liquid string container

3 © Raffles Institution 9749 [Turn over     (iii) Determine the magnitude of the average fo rce acting on the sphere during the first 4.5 s of its motion through the liquid. average force = N [2] (b) On Fig. 1.2, sketch the variation with time t of the displacement s of the sphere for the first 4.5 s of the sphere’s motion through the liquid. At t = 0, the string is cut and s = 0. Take the downwards direction to be positive. Fig. 1.2 [2] (c) The setup sh