2022 NCHS Phy Prelims P2

1 Name: Register Number: Class: NAN CHIAU HIGH SCHOOL PRELIMINARY EXAMINATION 2022 SECONDARY FOUR EXPRESS PHYSICS 6091/02 Paper 2 23 Aug 2022 Tuesday 1 hour 45 mins Candidates answer on the Question Paper. No additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, class and register number in the spaces provided on the question paper. You may use an HB pencil for any diagrams, graphs, tables or rough working. Write in dark blue or black pen. Do not use staples, paper clips, highlighters, glue or correction fluid or tape. The use of an approved calculator is expected, where appropriate. You may lose marks if you do not show your working or if you do not use appropriate units. Section A: 50 marks Answer all questions. Section B: 30 marks Answer all questions. Question 12 has a choice of parts to answer. The total mark for this paper is 80. Take gravitational field strength of Earth = 10 N kg-1 and acceleration due to gravity = 10 m s-2. This question paper consists of 20 printed pages, including this cover page. For Marker’s Use Parent’s Signature: ________________

2 Section A Answer all the questions in this section 1 Fig. 1.1 (not drawn to scale) shows the side view of a steel ball 2.0 kg suspended by 2 strings attached to the ceiling. String 1 and string 2 are 35o and 55o from the vertical respectively. The tensions in strings 1 and 2 are T1 and T2 respectively. Fig. 1.1 (Side view) (a) State and explain if the ball is at equilibrium. [2] ………………………………………………………………………………………………………. ………………………………………………………………………………………………….….... …………………………………………………………………………………………………...….. (b) Calculate the weight of the ball. [1] (c) Draw the weight and label it as W in Fig. 1.1. [1] 2.0 kg T2T1 ceiling 35 º 55 º

3 (d) By drawing a scaled vector diagram below, determine the magnitudes of tension T1 and tension T2. [3] Tension T1 = _____________ Tension T2 = _____________

4 2 A rock is travelling in a straight line downwards at high speed in air when it enters a deep pond. Fig. 2.1 shows the speed-time graph of the rock from time t = 0 s to time t = 50 s. Fig. 2.1 (a) On Fig 2.1, mark on the graph with a point and label it D, when the rock has increasing deceleration. [1] (b) Calculate the deceleration of the rock at t = 25 s. [2] (c) Describe and explain what happens to the motion of the rock at t = 40 s. [2] …………………………………………………………………………………………………….…. ………………………………………………………………………………………….……………. Speed / mm s-1 time t/s

5 3 Fig. 3.1 shows a 600 N man standing on the second rung of a 25 N ladder. (a) State the Principle of Moments. [2] ………………………………………………………………………………………………………. ………………………………………………………………………………………………………. (b) Calculate the normal reaction force RB. [2] (c) The man climbs up the ladder. State what happens to the position of the centre of gravity and the stability of the man-ladder system. [2] ………………………………………………………………………………………………………. .…………………………………………………………………………………………………….... 25 N Fig. 3.1 90 cm 600 N 40 cm RB 80 cm

6 4 Fig. 4.1 shows an experiment to analyse the motion of a 5.0 kg stone dropping from rest from two very different heights from the ground. In this experiment, air resistance is assumed to be negligible. (a) Define gravitational field strength. [1] ………………………………………………………………………………………………………… (b) The stone is dropped from a height of 40 m from the ground. On the axes given in Fig. 4.2, sketch the graph of the (i) gravitational potential energy, label it as P, of the stone against the height, h from ground, and (ii) kinetic energy, label it as K, of the stone against the height, h from the ground. [3] The graphs drawn should clearly show the relationship between P and K. No numerical value is required for the graphs. (c) The gravitational field strengths of the Earth at heights of 40 m and at 40 km are 10 N kg-1 and 9.7 N kg-1 respectively. Calculate the change in potential energy of the stone when it falls from 40 km to 40 m. [2] stone Fig. 4.1 h Fig. 4.20 h /m Energy / J

7 5 Fig. 5.1 shows the landscape of a mountain. The reading of a mercury barometer at the foot of the mountain is 76.0 cmHg. On point P, the summit of the mountain, its reading drops to 70.0 cmHg. The density of mercury is 13 600 kg m-3 and the density of air is 1.23 kg m-3. (a) Calculate the height of the mountain. [3] (b) Explain in terms of molecules, why the boiling point of pure water is not 100 oC at point P. [2] …………………………………………………………………………………………………………... …………………………………………………………………………………………………………… …………………………………………………………………………………………………………… …………………………………………………………………………………………………………… …………………………………………………………………………………………………………… P Fig. 5.1

8 6 Fig. 6.1 shows an uncalibrated mercury thermometer first placed in a plastic box with 300 ml of crushed ice. After 10 seconds, the height of the mercury column was marked with a thick blue marker. The uncalibrated thermometer was then placed in 500ml of hot water heated over a stove at a constant 80 °C. When the height of the mercury column had stabilised after 2 minutes, the new height of the mercury column was marked with a thick red marker. The length between both markings were then divided into divisions of 10 °C and marked accordingly. Suggest three ways you can improve this calibration process. [3] ……………………………………………………………………………………………..………….….. …………………………………………………………………………………………………………….. …………………………………………………………………………………………………………….. …………………………………………………………………………………………………………….. …………………………………………………………………………………………………………….. …………………………………………………………………………………………………………….. …………………………………………………………………………………………………………….. …………………………………………………………………………………………………………….. Hot water at 80 °C Crushed ice at 0 °C Fig. 6.1 Mercury column

9 7 Fig. 7.1 shows a negative charged metal plate X, an uncharged metal plate Y and a connection to earth. Plate X and Plate Y are on insulating stands. (a) Explain what is meant by electrostatic induction. [1] ……………………………………………………………………………………………………..… ……………………………………………………………………………………………………….. (b) Explain why insulators cannot be charged by electrostatic induction. [1] ………………………………………………………………………………………………..………. …………………………………………………………………………………………………..……. ………………………………………………………………………………………………..………. (c) With the aid of the apparatus shown in Fig 7.1, describe clearly the steps to obtain a positively-charged plate Y. [2] ………………………………………………………………………………………………………... …………………………………………………………………………………………………….….. ………………………………………………………………………………………………….…….. ……………………………………………………………………………………………….……….. ……………………………………………………………………………………………….……….. ……………………………………………………………………………………………….………