2024 CHR Physics Prelim P2

This Question Paper consists of 22 printed pages including this cover page. 1 CHR 2024/Physics 6091/02/O [Turn over CHRIST CHURCH SECONDARY SCHOOL 2024 PRELIMINARY EXAMINATION FOUR EXPRESS PHYSICS 6091/02 Paper 2 20 Aug 2024 1 hour 45 minutes Candidates answer on the Question Paper No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, class register number and class in the spaces p rovided at the top of this paper and all the work you hand in. You may use an HB pencil for any diagrams, graphs. Do not use staples, paper clips, highlighters, glue or correction fluid. Section A Answer all questions. Write your answers in the spaces provided. Section B Answer one question. Write your answers in the spaces provided. Students are reminded that all quantitative answers should include appropriate units. The use of approved scientific calculator is expected where appropriate. Students 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. CANDIDATE NAME CLASS CENTRE NUMBER S INDEX NUMBER

Christ Church Secondary School Secondary Four Express 2024 Preliminary Examination Physics CHR Preliminary Exam 2024 / Pure Physics 6091/02/O 2 1 Section A Answer all the questions in this section. Fig. 1.1 shows a CHRian stationary on a Zipline. Two contact forces, tensions, T1 and T2 are acting on the rope as shown. To keep stationary, a third, non -contact force is acting on this CHRian by the gravitational field of the earth. (a) State what is meant by the gravitational field. ………………………………………………………………………………………………….. ………………………………………………………………………………………………..[1] (b) Given that T1 and T2 are each 850 N and tilted at an angle of 15 from the horizontal, Use a vector diagram, determine the resultant force from these two tensions. State clearly the scale used. scale:….……………………………[1] resultant force =……………………………….[2] Fig. 1.1 (not to scale) T1 T2 15 15

Christ Church Secondary School Secondary Four Express 2024 Preliminary Examination Physics CHR Preliminary Exam 2024 / Pure Physics 6091/02/O 3 2 (c) Explain, by applying Newton’s Law, how the answer to (b) can be used to determine the magnitude and direction of the non-contact force. ………………………………………………………………………………………………….. ………………………………………………………………………………………………….. ………………………………………………………………………………………………….. ………………………………………………………………………………………………..[2] [Total: 6] Fig. 2.1 shows a wind turbine used to generate electricity. (a) The wind blows directly towards the turbine with a speed of 12 m/s. In one second, 65 000 kg of air passes through the circular area swept out by the rotor blades. Calculate the energy in the kinetic store of this mass of air in one second. energy in the kinetic store = …………………….[2] Fig. 2.1 65 000 kg of air passes through this circular area in one second rotor blade [Turn over

Christ Church Secondary School Secondary Four Express 2024 Preliminary Examination Physics CHR Preliminary Exam 2024 / Pure Physics 6091/02/O 4 (b) Given that the efficiency of this wind turbine is 72%. Calculate the amount of electrical power generated. electrical power = ……………………………..[1] (c) Using the principle of conservation of energy and energy stores, describe how energy transfer takes place in the wind turbine. …………………………………………………………………………………………….. …………………………………………………………………………………………….. …………………………………………………………………………………………….. ………………………………………………………………………………………….[2] (d) The potential difference between the electrical turbine is 3.5 MV. Calculate the electric current produced. current = ………………………..[2] [Total: 7]

Christ Church Secondary School Secondary Four Express 2024 Preliminary Examination Physics CHR Preliminary Exam 2024 / Pure Physics 6091/02/O 5 3 Fig. 3.1 shows a toy water rocket. The rocket is half-filled with water and connected by rubber tubing to a pump. Air is then pumped into the rocket so that the pressure in the rocket increases. (a) Explain, using ideas about molecules, why pumping air in the rocket increases the pressure in the rocket. …………………………………………………………………………………………….. …………………………………………………………………………………………….. …………………………………………………………………………………………….. …………………………………………………………………………………………..[2] (b) State and explain, using ideas about molecules, how the pressure of the air in the rocket would change when the temperature of the air in the rocket is increased. …………………………………………………………………………………………….. …………………………………………………………………………………………….. …………………………………………………………………………………………….. …………………………………………………………………………………………..[2] [Total:4] Fig. 3.1 air pump rubber tubing water rocket air [Turn over

Christ Church Secondary School Secondary Four Express 2024 Preliminary Examination Physics CHR Preliminary Exam 2024 / Pure Physics 6091/02/O 6 4 Fig. 4.1 shows a tank with a base area of 5.0 m2 connected at the bottom via a horizontal pipe to a vertical tube of cross-sectional area 0.10 m2. Both the tank and the vertical tube are exposed to the atmosphere. A liquid of density 900 kg/m3 is poured into the tank to a depth of 0.40 m. (a) On Fig. 4.1, clearly show the depth of liquid in the vertical tube. [1] (b) Calculate the mass of liquid in the tank only. (You may ignore the volume of pipe). mass of liquid in the tank = …………………..[2] (c) Calculate the total pressure at point X indicated on Fig. 4.1. Given that the atmospheric pressure is 100 kPa. Take g = 10 N/kg. total pressure = …………………………….[3] [Total: 6] 0.40 m Fig. 4.1 (not draw to scale) 5.0 m2 0.10 m2 vertical tube pipe tank X

Christ Church Secondary School Secondary Four Express 2024 Preliminary Examination Physics CHR Preliminary Exam 2024 / Pure Physics 6091/02/O 7 5 Fig. 5.1 shows a geothermal reservoir. (a) 1500 kg of cold water at a temperature of 25 C is pumped down to the hot rocks. The water rises back up as 50% hot water and 50% steam. Both the stea