2022 VS Phy Prelims P1&2 Ans

Physics Prelim 2022 Answers 1 2 3 4 5 6 7 8 9 10 B D B C C C A B C B 11 12 13 14 15 16 17 18 19 20 D D C D D A A C A B 21 22 23 24 25 26 27 28 29 30 D B D D A A D D C D 31 32 33 34 35 36 37 38 39 40 B A C A C A A D B C Suggested Solution 1 (a)(i) Density is defined as mass per unit volume. (a)(ii) Mass of a 1 m3 = density x volume cube of limestone = 2.71 x (50)3 g = 340 kg (correct to 2 s.f.) (shown) (b)(i) . (b)(ii) Take y to be the number of identical limestone blocks that can be lifted. Taking moments about the front wheel, Sum of clockwise moments = Sum of anti-clockwise moments (1000) x (1.0) x (10) = (340) x (0.9) x (10) x (y) y = 3.27 blocks Therefore the maximum number of blocks is 3. Suggested Solution 2 (a) Increase in gravitational = mg∆h potential energy of ball = (0.60)(10)(5) = 30 J (b) Kinetic energy at A = Potential energy at B + Kinetic energy at B = 30 J + 8.5 J = 38.5 J Force on rear tyre by ground. Force on front tyre by ground. weight of forklift. force on forklift by limestone

2 © VICTORIA SCHOOL 22/4P/6091/02 (c) The student is incorrect as weight is the only force acting on the basketball after it leaves the student’s hand. And weight is the resultant force that causes the (downwards) acceleration of the basketball rather than an upwards acceleration that explains the motion of the ball upwards. Suggested Solution 3 (a) Pressure at X = (0.76)(13600)(10) = 1.03 x 105 Pa (b)(i) (ii) Pressure of trapped gas= Atmospheric Pressure + Pressure due to 10 cm Hg = 76 cm Hg + 10 cm Hg = (86 x 10-2)(13 600)(10) = 1.17 x 103 Pa Both levels are correctly drawn at 55 cm (c) The pressure at Y is still 76 cm Hg as the additional pressure is due to the reaction force acting downward on mercury column by barometer. Suggested Solution 4 (a) (b) The water particles are in constant random motion and slide over one another. 1. As the liquid is heated, its temperature increases that cause the average speed of the particles to increase. 2. This leads to a higher force per collision and higher rate of collision with the walls of the container. Force exerted per unit area increases causing a rise in pressure. (c) Number of divisions between ice point and steam point = 10 divisions Number of divisions from ice point = 6 divisions Temperature of unknown liquid = 6 10 × 100 °C = 60 °C Or any other relevant mathematical calculations Suggested solution 5 (a) It means there is 2 complete rotations/waves produced per second. (b) f = 2 × 8 = 16 Hz v = f λ 330 = 16 × λ λ = 20.6 m (c) New waveform has half the original amplitude (0.5 d). It will have a period that is doubled. So will show 1.75