Materials For this paper you must have: • a pencil and a ruler • a scientific calculator • a Data and Formulae Booklet • a protractor. Instructions • Use black ink or black ball-point pen. • Fill in the boxes at the top of this page. • Answer all questions. • You must answer the questions in the spaces provided. Do not write outside the box around each page or on blank pages. • If you need extra space for your answer(s), use the lined pages at the end of this book. Write the question number against your answer(s). • Do all rough work in this book. Cross through any work you do not want to be marked. • Show all your working. Information • The marks for questions are shown in brackets. • The maximum mark for this paper is 35. • You are expected to use a scientific calculator where appropriate. • A Data and Formulae Booklet is provided as a loose insert. Please write clearly in block capitals. Centre number Candidate number Surname Forename(s) Candidate signature I declare this is my own work. A-level PHYSICS Paper 3 Section B Engineering physics Time allowed: The total time for both sections of this paper is 2 hours. You are advised to spend approximately 50 minutes on this section. 2 *02* IB/M/Jun24/7408/3BC There are no questions printed on this page DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED Do not write outside the box 3 *03* Turn over ► IB/M/Jun24/7408/3BC Do not write outside the Section B box Answer all questions in this section. 0 1 A heavy turntable is mounted on a fixed base. The turntable can rotate freely on a low-friction bearing. 0 1 . 1 Figure 1 shows a propeller unit fixed to the centre of the turntable. The propeller unit consists of a motor-driven propeller and a battery. The propeller and the turntable have a common axis of rotation. Figure 1 At first, the turntable and the propeller are at rest. The propeller motor is switched on and the propeller quickly reaches a high final angular speed. The propeller rotates clockwise when viewed from above. Compare, with reference to angular momentum, the motions of the turntable and the propeller. [3 marks] Question 1 continues on the next page 4 *04* IB/M/Jun24/7408/3BC Do not write outside the 0 1 box . 2 Figure 2 shows an arrangement used to determine the moment of inertia of the turntable. Figure 2 A small steel mass is held by an electromagnet above the top surface of the turntable. The diameter of the turntable is about half a metre. The turntable rotates freely at an initial angular speed ω1. The switch is opened so that the mass falls and sticks to the surface of the turntable. This changes the angular speed of the turntable to ω2. The steel mass can be considered to be a point mass. Describe how to determine the moment of inertia of the turntable using observations of ω1 and ω2. In your answer you should: • suggest how ω1 and ω2 are measured • state any other measurements needed and name the equipment used to make them • explain how the moment of inertia of the turntable is determined from the measurements. [6 marks] 5 *05* Turn over ► IB/M/Jun24/7408/3BC Do not write outside the box 9 6 *06* IB/M/Jun24/7408/3BC Do not write outside the There are no questions printed on this page box DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED 7 *07* Turn over ► IB/M/Jun24/7408/3BC Do not write outside the 0 2 box Figure 3 shows an excavator. Figure 3 The bucket position can be changed by moving the boom and arm and by rotating the platform about the vertical axis of rotation. For the purposes of this question, assume that the excavator tracks do not move.