SJI 2020 Year 3 EOY Physics 6091 P2

Section A 1 2 3 4 5 6 7 8 Section B 9 10 11 For Examiner’s Use Sect. A / 40 Sect. B / 30 Total / 70 ST JOSEPH’S INSTITUTION END-OF-YEAR EXAMINATION 2020 (YEAR 3) CANDIDATE NAME CLASS INDEX NUMBER PHYSICS Paper 2 Additional Materials: Nil 6091/02 5 OCTOBER 2020 1 hour 40 minutes (08:00 – 09:40) READ THESE INSTRUCTIONS FIRST Write your name, class and index number on the cover page of this Question Paper and all the work you hand in. Write in dark blue or black pen on both sides of the paper. You may use a soft pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Section A and B Answer all questions on the Question paper. Candidates are reminded that all quantitative answers should include appropriate units. Candidates are advised to show formulae and all their working in a clear and orderly manner, as more marks are awarded for sound use of Physics than for correct answers. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. This document consists of 18 printed pages including this cover page

2 width : 0.594 m length : 0.841m A1 size Section A (40 marks) Answer all questions in this section. 1 In a prac tical session, a student is required to measure the thickness of a piece of graph paper. Fig. 1.1 shows the reading of the micrometer used to measure 100 pieces of graph papers. Fig. 1.1 (a) Determine the thickness of one piece of graph paper in metre and in standard form. thickness = ……………………….. [2] (b) The term GSM (grams per square meter) is a measure of the mass of various types of paper from a sample sheet cut to one square meter. The heavier the paper, the higher the GSM. The student bought a piece of A1 size cardboard rated at 400 GSM as shown in Fig. 1.2. Fig. 1.2

3 (i) Calculate the volume of the cardboard in m 3, given that it has a thickness of 0.22 mm. volume = ……………………….. [2] (ii) Using the GSM of the paper, calculate the mass, and hence the density of the A1 sized cardboard in kg/m3. density = ……………………….. [2]

4 2 In a bungee jump, a fixed rubber cord is fastened to the jumper’s ankles to stop his fall. Fig. 2.1 shows how the velocity of the bungee jumper changes during the first 6.0 s after he made the jump off a cliff. Fig. 2.1 (a) Calculate the acceleration of the jumper between t = 1.0 and 3.0 s. acceleration = ……………………….. [1] (b) Describe how the motion of the jumper changes between t = 3.0 s and 6.0 s. ……………………………………………………………………………………………... ……………………………………………………………………………………………... ……………………………………………………………………………………………... ………………………………………………………………………………………..…[2] (c) Determine the displacement of the jumper at t = 6.0 s, from where he jumped off. displacement = ……………………….. [2]

5 (d) Calculate the average speed of the jumper for the duration of 6.0 s. average speed = ……………………….. [2] (e) Explain why the average speed of the jumper is higher than his average velocity. ……………………………………………………………………………………………... ……………………………………………………………………………………………... …………………………………………………………………………………………..[1] 3 A physicist brought a mercury manometer with him to check the air pr essure in an aircraft’s cabin when he was taking a flight. Fig. 3.1 shows the manometer. The left limb is connected to a gas container while the right limb is exposed to the cabin air. The gas pressure in the container is 40.0 cmHg. The density of mercury is 13 600 kg/m3. The gravitational field strength g = 10 N/kg. Fig. 3.1 (a) Express the gas pressure in the container in Pa. pressure = ……………………….. [1]

6 (b) Determine the air pressure in the cabin in cmHg. pressure = ……………………….. [1] (c) The air pressure in the cabin suddenly dropped during the flight. State and explain how h1 and h2 changed. ……………………………………………………………………………………………... ……………………………………………………………………………………………... ………………………………………………………………………………………..…[2] (d) When the aircraft is flying at a n altitude of 12 000 m, the atmospheric pressure outside the aircraft decreases significantly to 20 000 Pa. To create a safe and comfortable environment for the passengers, the cabin is pressur ised and the air pressure in the cabin is kept at 80 000 Pa. (i) Explain why atmospheric pressure decreases at higher altitude. ……………………………………………………………………………………... ……………………………………………………………………………………... …………………………………………………………………………………..[1] (ii) The area of one panel of the window in the cabin is 875 cm 2, determine the force exerted by the air inside the cabin on the window. force = ……………………….. [2]

7 4 Fig. 4.1 shows a toy car of mass 1.0 kg that is moving towards the edge of a ramp. Fig. 4.1 At the end of the horizontal section of the track, the car acceler ates down the rough surface of the ramp of length 0.90 m , achieving a speed of 2.5 m/s at the end of the ramp. The effect of air resistance is negligible. (a) Explain how the principle of conservatio n of energy is applied as the toy car moves down the ramp. ……………………………………………………………………………………………... ……………………………………………………………………………………………... ……………………………………………………………………………………………... ……………………………………………………………………………………………... ………………………………………………………………………………………..…[2] (b) (i) Calculate the change in gravitational potential energy of the toy car as it moves down the ramp. The gravitational field strength g = 10 N/kg. energy = ……………………….. [1]

8 (ii) Given that the average frictional force between the toy car and the ramp is 0.11 N, determine the speed of the toy car at the top of the ramp. speed = ……………………….. [2] (c) The initial speed of the toy car is now doubled. Explain why this does not result in an increase in the speed of the toy car at the bottom of the ramp to 5.0 m/s. ……………………………………………………………………………………………... ……………………………………………………………………………………………... ………………………………………………………………………………………..…[1] 5 An aluminum can with an opening on the top contains a small amount of water that is heated until the water boils. (a) Explain why the air particles in the aluminium can exert pressure onto the wall of the can. ……………………………………………………………………………………………... ……………………………………………………………………………………………... ……………………………………………………………………………………………... ………………………………………………………………………………………..…[2] (b) Explain why the heated aluminium can finally crumple s when it is completely immersed in cold water, immediately after being heated. ……………………………………………………………………………………………... ……………………………………………………………………………………………... ……………………………………………………………………………………………... ………………………………………………………………………………………..…[2]

9 6 Fig. 6.1 shows the structure of a water cooler that is used to supply cold water. Fig. 6.1 Water in the tank is being cooled before being dispensed through the tap. A cold liquid from the refrigeration unit is pumped through the copper pipe and thermal energy from the water is transferred through the copper pipe to this liquid. (a) Explain, in terms of particles, how thermal energy is transferred th rough the copper pipe. ……………………………………………………………………………………………... ……………………………………………………………………………………………... ………………………………………………………………………………………......[2] (b) The water surrounding the copper pipe is cooled. Explain how this helps to decrease the temperature of the water in the tank. ……………………………………………………………………………………………... ……………