2025 TKGS Pure Physics Prelim P2

Tanjong Katong Girls’ School 2 Sec 4 Preliminary Examination 2025 Section A Answer all questions in this section. 1 Fig 1.1 shows an arrow about to be released. When the bowstrings are stretched to the extent shown in Fig. 1.1, the tension in each of the bowstrings is 80 N, while the angle between the bowstring and arrow is 45°. Draw a scaled vector diagram to determine the magnitude of the resultant force acting on the arrow due to the bowstrings just before it is released. scale = .............................................. magnitude of resultant force = ..............................................[4] [Total: 4] 2025 Phy Set 7

Tanjong Katong Girls’ School 3 Sec 4 Preliminary Examination 2025 2 Fig. 2.1 shows a child sliding down a slope on a snow sledge. Fig 2.1 At time t = 0, the child and the sledge begin to move down the hill. When the child sees a wall ahead, he applies the brake and eventually comes to a stop. Fig. 2.2 shows the velocity time graph of the journey. Fig 2.2

Tanjong Katong Girls’ School 4 Sec 4 Preliminary Examination 2025 (a) Explain, using ideas of forces, why the speed varies in the way shown in Fig 2.2 between t = 0 s and t = 26 s. ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………[3] (b) Explain how the graph shows that the child and the sledge reach terminal velocity. ………………………………………………………………………………………………… ………………………………………………………………………………………………[1] (c) At t = 26 s, the front of the sledge is 35 m away from the wall. Determine if the child is able to come to a stop before hitting the wall. ………………………………………………………………………………………………… ………………………………………………………………………………………………[2] (d) State the main energy changes during time t = 24 s to t = 26 s. ………………………………………………………………………………………………… ………………………………………………………………………………………………[1] (e) At t = 26 s, when the brakes are first applied, the child jerks forward on the sledge. Explain why this happens. ………………………………………………………………………………………………… ………………………………………………………………………………………………[1] [Total: 8]

Tanjong Katong Girls’ School 5 Sec 4 Preliminary Examination 2025 3 Fig 3.1 shows a crane with a boom angle of 30° used on construction sites to lift heavy loads. The length of the crane boom is 45.0 m and the perpendicular distance of the load to the pivot X is 22.0 m. Fig 3.1 Table 3.1 shows the maximum load the crane can support at different boom angles. boom angle / ο maximum load / N 30 11 500 45 14 000 60 20 000 Table 3.1 . (a) Explain why the maximum load increases as the boom angle increases. …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………[2] pivot

Tanjong Katong Girls’ School 6 Sec 4 Preliminary Examination 2025 (b) (i) Calculate the maximum moment that the crane can support when the boom angle is 30o. maximum moment = …………………………[2] (ii) Given that the counterweight is 5.0 m away from pivot X when the boom angle is 30o, calculate the weight of the counterweight. weight = ……………………[2] Total: [6]

Tanjong Katong Girls’ School 7 Sec 4 Preliminary Examination 2025 4 Fig. 4.1 shows a U-tube which contains mercury being used as a manometer to measure the pressure from a gas supply in a container. One end of the tube is connected to the gas supply and the other end is open. Fig. 4.1 (a) Describe how gas molecules create a pressure with the gas supply. ………………………………………………………………………………………………… ………………………………………………………………………………………………[1] (b) Explain why the mercury level moves down on the left side of the U-tube when the gas supply is connected. ………………………………………………………………………………………………… ………………………………………………………………………………………………[1] (c) Given that the density of mercury is 13 600 kg/m 3 and the atmospheric pressure is 760 mm Hg, calculate the pressure of the gas supply in pascal. pressure = ……………………………. [2]

Tanjong Katong Girls’ School 8 Sec 4 Preliminary Examination 2025 (d) The gas supply is made to cool down to a lower temperature. Describe and explain the effect on the difference in the mercury levels between the left and right side of the U-tube. ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………[3] [Total: 7]

Tanjong Katong Girls’ School 9 Sec 4 Preliminary Examination 2025 5 In a company that manufactures frying pans, a researcher wishes to select a new material that can be used for the base of the pan. Table. 5.1 shows four possible materials and their properties. Table 5.1 material melting point / °C specific heat capacity / J/(kg °C) A 2350 900 B 950 480 C 1600 480 D 7800 130 (a) The researcher carries out a series of experiments on the materials. (i) In one of the experiments, a 2.0 kg sample of material A is heated by an electrical heater of power 450 W. The initial temperature of the sample is 25 °C. Calculate the time taken for the temperature of the sample to rise to 100 °C. time taken = …………………[2] (ii) Using the data in Table 5.1, discuss which material is the most suitable to be used for the base of the frying pan. Give one reason to support your choice. …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………[2]

Tanjong Katong Girls’ School 10 Sec 4 Preliminary Examination 2025 (b) 2.3 kg of hot water at boiling point is poured into the frying pan. 5 190 000 J was supplied to convert all the water into steam. Calculate the specific latent heat of vaporisation of water. specific latent heat of vaporisation= ……………………[2] [Total: 6]

Tanjong Katong Girls’ School 11 Sec 4 Preliminary Examination 2025 6 A water wave is travelling from left to right across the water surface of a pond at a speed of 24 cm/s. Fig 6.1 shows a snapshot of the wave at a certain instant. R and S are two water particles on the water surface. R makes 45 complete oscillations in one minute. Fig 6.1 (a) State the type of wave generated. Explain your answer. ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………[2] (b) Calculate (i) the time taken for R to reach the highest point, time taken = ……………………………. [2] (ii) the distance between R and S. distance = ……………………. [2] [Total: 6]