NTSS Prelim P2 Ans

NEW TOWN SECONDARY SCHOOL PRELIMINARY EXAMINATION 2024 Secondary 4 Express NAME CLASS INDEX NO. PHYSICS 6091 [Revised]/02 Paper 2 22 Aug 2024 1 hour 45 minutes Candidates answer on the Question Paper. 0800 – 0845 Additional Materials: NIL READ THESE INSTRUCTIONS FIRST Write your name, index number and class on all the work you hand in. Write in dark blue or black pen on both sides of the paper. Do not use staples, paper clips, highlighters, glue or correction fluid. Section A (70 marks) Answer all questions. Section B (10 marks) Answer any one question. Candidates are reminded that all quantitative answers should include appropriate units. The use of an approved scientific calculator is expected, where appropriate. Candidates are advised to show all their working in a clear and orderly manner, as more marks are awarded for sound use of Physics than for correct answers. The number of marks is given in brackets [ ] at the end of each question or part question. For Marker’s Use Section A Section B Total This document consists of 24 printed pages and 0 blank page.

2 Section A (70 marks) Answer all the questions in the spaces provided. 1 A man stands at the edge of a vertical cliff and he projects a stone vertically upwards. The stone reached its greatest height, fell past the man and hit the bottom of the cliff. The motion of the stone is represented by the velocity-time graph shown in Fig. 1.1. Fig. 1.1 (a) Explain how Fig. 1.1 shows that air resistance has negligible effect (C) on the motion of the stone. Stone has a constant acceleration (E) indicating free-fall acceleration (R). OR Graph has a constant gradient indicating free-fall acceleration. -Accept: a= 10m/s2 which is acceleration due to gravity -Majority wrote ‘constant acceleration/ gradient’ (E) without the (R) [1] (b) Based on the data shown in Fig. 1.1, determine the greatest height achieved by the stone. Greatest height = area under v-t graph (first 2.0 s) = ½(2.0)(20) [1] = 20 m [1] Most did well greatest height = ………………………. [2] [Total: 3 marks]

3 2 Fig. 2.1 shows the vertical forces acting on a weather balloon just after lift-off. Fig. 2.1 The balloon experiences an upward force of 95 N. The total weight of the balloon and its contents is 61 N. (a) Determine the total mass of the balloon and its contents. The gravitational field strength g is 10 N/kg (F) m = W / g (S) = 61/ 10 (AU) = 6.1 kg [1] total mass = ………………………. [1] (b) Calculate the initial vertical acceleration of the balloon. Fnet = 95 – 61 = 34 N a = Fnet / m = 34/ 6.1 =5.57 m/s2 [1] acceleration = ………………………. [1]