2019 RI Prelims Paper 3 Sect B QP

This document consists of 8 printed pages. © Raffles Institution [Turn over Centre Number Index Number Name Class S3016 RAFFLES INSTITUTION 2019 Preliminary Examination PHYSICS Higher 2 Paper 3 Longer Structured Questions 9749/03 27 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. Section A Answer all questions. Section B Answer one question only and circle the question number on the cover page. You are advised to spend one and half hours on Section A and half an hour on Section B. The number of marks is given in brackets [ ] at the end of each question or part question.  This booklet only contains Section B. For Examiner’s Use Section B (circle 1 question) 8 / 20 9 / 20

2 © Raffles Institution Section B Answer one question from this Section in the spaces provided. 8 (a) State Newton’s Second Law. [2] (b) A toy truck of mass 1.0 kg is moving in a straight line on a horizontal surface as shown in Fig. 8.1. The toy truck has a cargo compartment at the back with an open top. Air resistance is negligible. (i) If the engine of the toy truck delivers a c onstant driving force of 0.0050 N, calculate the impulse of the drivin g force for a duration of 30 s. impulse = N s [1] (ii) The toy truck was moving with a speed of 0.20 m s −1 when it started to rain. The rain droplets fall vertically and collect in the cargo compartment. Show that the horizontal momentum of the truck and the rain droplets collected 30 s after the rain started is 0.35 N s. horizontal momentum = N s [1] open top direction of motion horizontal surface Fig. 8.1

3 © Raffles Institution [Turn over (iii) The rain droplets collect in the cargo compartment at a rate of 0.0325 kg s −1. 1. Calculate the total mass of the toy truck and the droplets collected at the end of the 30 s duration. total mass = kg [1] 2. Using your answer in (b)(ii), show that the final speed of the truck is 0.177 m s−1. [1] 3. Hence, state and explain the direction of the average acceleration of the toy truck. [2] 4. By considering the forces acting on the toy truck, explain why it slows down despite a forward driving force.