2022 ANDSS Phy Prelims P2

This document consists of 26 printed pages. Setter: Mr Richmond Ang O ANDERSON SECONDARY SCHOOL Preliminary Examination 2022 Secondary Four Express CANDIDATE NAME: CLASS: / INDEX NUMBER: PHYSICS Paper 2 Physics Candidates answer on the Question Paper. 6091/02 17 August 2022 1 hour 45 minutes 1110 – 1255 h No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, class and index number on all the work you hand in. Write in dark blue or black pen. You may use a pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid/tape. Section A Answer all questions. Section B Answer all questions. Question 12 has a choice of parts to answer. 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 Examiner’s Use Section A [50] Section B [30] Total [80]

2 PRELIM 4E PHY 2022 6091/2 Section A Answer all the questions in this section. 1 (a) Electric charge can be stated to be either positive or negative. State and explain whether electric charge is a scalar or a vector quantity. ……………………………………………………………………………………. …………………………………………………………………………….….. [1] (b) A potential difference is applied between a pair of horizontal metal plates in a vacuum as shown in Fig. 1.1. Fig. 1.1 A negatively charged particle enters the electric field at point X with a velocity of 0.75 m/s to the right. The particle is deflected by the field and hits the top plate at point Y. (i) Explain why the average velocity of the particle is lower than its average speed as it travels from point X to point Y. ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………... ……………………………………………………………………………... ……………………………………………………………………….…. [2]

3 PRELIM 4E PHY 2022 6091/2 (ii) On Fig. 1.2, draw and label all the forces acting on the particle at point X. Fig. 1.2 [2]

4 PRELIM 4E PHY 2022 6091/2 2 A block of weight 15N hangs by a wire from a remotely controlled aircraft, as shown in Fig. 2.1. Fig. 2.1 The aircraft is used to move the block only in a vertical direction. The force on the block due to air resistance is negligible. The variation with time t of the vertical velocity v of the block is shown in Fig. 2.2. The velocity is taken to be positive in the upward direction. Fig. 2.2

5 PRELIM 4E PHY 2022 6091/2 (a) Determine the displacement of the block from time t = 0 to t = 3.0 s. magnitude of displacement = ……………………… direction of displacement ………………….. [3] (b) (i) Calculate the magnitude of the acceleration of the block at time t = 2.0s. acceleration = …………………… [2] (ii) Use your answer in (b)(i) to calculate the tension in the wire at time t = 2.0s. The gravitational field strength acting on the block is 10 N/kg. tension = …………………[2] (c) The block is removed and replaced by a disc. The force on the disc due to air resistance is not negligible. On Fig. 2.2, draw a possible velocity-time graph of the disc as the aircraft is lifting it until its velocity reaches zero. [1]

6 PRELIM 4E PHY 2022 6091/2 3 Fig. 3.1 below shows a device that can be used to ignite small pieces of combustible material. The device consists of a cylinder containing trapped air and a piston. Fig. 3.1 A small piece of combustible material is placed at the bottom of the cylinder. When the piston is pushed quickly into the cylinder, the trapped air is compressed and heats up. This increase in temperature is enough to ignite the combustible material. The piston is quickly pushed down a distance of 14.5 cm. The average force exerted on the piston is 4.7 N. (a) Calculate the work done on the trapped air when the piston is quickly pushed down. work done = ………….. [2] (b) Suggest why the trapped air does not reach a high enough temperature to ignite the combus tible material if the piston is slowly pushed into the cylinder. ……………………………………………………………………………………. ……………………………………………………………………………………. …………………………………………………………………………….….. [1]

7 PRELIM 4E PHY 2022 6091/2 4 Fig. 4.1 shows a diver using a canister of compressed air so that he can breathe underwater. Fig. 4.1 (a) Describe the motion of the air particles in the canister. ……………………………………………………………………………………. ………………………………………………….…………………………….. [1] (b) A canister of air was tested to find out how the pressure changed when it was used by a diver. • Air was allowed to escape from the canister • The pressure of the air inside the canister was recorded every 5 minutes for 80 minutes. Fig. 4.2 shows the results. Fig. 4.2 (i) Using Fig. 4.2, estimate the atmospheric pressure. atmospheric pressure = …………….. [1]

8 PRELIM 4E PHY 2022 6091/2 (ii) Divers can safely stay underwater as long as the pressure of the air in the canister is higher than the surrounding pressure. Determine the maximum amount of time a diver can stay safe at 40 m below the surface of the sea. The density of sea water is 1025 kg/m3. maximum amount of time= ……………… [2] 5 (a) State the principle of moments. ………………………………………………………………………………........... ………………………………………………………………………………........... ….…………………………………………………………………………........ [2] (b) In a bicycle shop, two wheels hang from a horizontal un iform rod AC, as shown in Fig. 6.1. Fig. 6.1 The rod has weight 19N and is freely hinged to a wall at end A. The other end C of the rod is attached by a vertical elastic cord to the ceiling. The centre of gravity of the rod is at point B. The weight of each wheel is W and the tension in the cord is 22N.

9 PRELIM 4E PHY 2022 6091/2 (i) By taking moments about end A, show that the weight W of each wheel is 14N. [2] (ii) Determine the magnitude and the direction of the force acting on the rod at end A. force at end A = ........................................ [1] 6 (a) In an experiment, a student inserts a wooden r od into the end of a brass tube as shown in Fig. 6.1. Fig. 6.1 She then wraps a paper collar around the joint and heats the apparatus, as shown in the Fig. 6.2. Fig. 6.2 Explain why the paper burns on the wooden rod, but not on the brass tube. ………………………………………………………………………………….….. ………………………………………………………………………………….….. ………………………………………………………………………………….….. ………………………………………………………………………………..… [2]

10 PRELIM 4E PHY 2022 6091/2 (b) A man closes a plastic bag with some ice cubes inside, as shown in Fig. 6.3. Fig. 6.3 (i) Describe briefly the processes on how the ice cubes inside the plastic bag gain thermal energy as they melt. ………………………………………………………………………………... ……………………………………………………………………………..…. ………………………………………………………………………………... ………………………………………………….........…………………… [2] 7 A ray of white light enters into a plastic tube which has a refractive index of 1.55 as shown in Fig. 7.1. (a) What is meant by a refractive index of 1.55? ……………………………………………………………………………………. ……………………………………………………………………………….... [1] (b) Determine the critical ang