2023 HCI Prelim P1 AS

2023 HWA CHONG INSTITUTION (COLLEGE SECTION) C2 © Hwa Chong Institution 1 2023 C2 H1 Physics Prelim Exams Paper 1 Suggested Solutions 1 A 6 C 11 B 16 D 21 C 26 D 2 D 7 B 12 C 17 D 22 B 27 B 3 B 8 D 13 C 18 B 23 B 28 D 4 B 9 B 14 A 19 C 24 C 29 D 5 C 10 C 15 A 20 C 25 B 30 C 1 A unit of magnetic flux density, B = unit of (F/IL) T = (kg m s-2) A-1 m-1 = kg s-2 A-1 2 D intensity I = Power P / surface area A     2 22 4 4 4 2.0 0.25 12.566 W P r P r        I I 2 0.05 0.12 0.312.566 0.25 2.0 4W P r P r P P                 I I 3 B Student electronic charge, e / x 10-19 C mean value spread A 1.62 1.59 1.59 1.61 1.60 1.60 0.03 B 1.57 1.63 1.64 1.58 1.59 1.60 0.07 C 1.59 1.60 1.58 1.57 1.57 1.58 0.03 D 1.58 1.62 1.65 1.59 1.66 1.62 0.08 Student B’s results have mean value = 1.60 x 10-19 C, which are accurate. However, his results have the largest spread (random errors), thus are least precise. 4 B Total displacement by car = [(10)(3.0)] + [-(5)(6.0)] = 0 m Average velocity of toy car = total displacement 0 total time taken 15 = 0 m s-1 5 C Sketch the v-t graph for train. Let tstations be the time taken by the train to travel between the two stations. Total distance travel by train between the two stations = 3000 m [(0.5(20)(100))]+[(20)( tstations – 150)]+[(0.5)(20)(50)] = 3000 tstations = 225 s = 230 s (2 s.f.) 6 C The speed of the projectile is the magnitude of the resultant velocity of the horizontal and vertical components velocities. As the projectile rises to the highest point, its speed decreases. As the projectile falls from the highest point, its speed increases. At the highest point, the speed is not zero as the projectile still has horizontal component velocity.

2 © Hwa Chong Institution 2 7 B The acceleration is downwards as the lift is ascending (i.e. velocity vector is upwards). Thus resultant force is downwards. The magnitude of the force exerted on the block by the floor (upwards) is always less than the magnitude of his weight (downwards). 8 D Constant force F = ma, thus acceleration is constant. Using equation of motion, v2 = u2 + 2as Since it starts from rest, u = 0, 2v ad Momentum p = mv = 2m ad Thus p is directly proportional to the square root of d. 9 B Let cross-sectional area of the stream of water be A, Rate of mass of water hitting wall 1000 8.0 8000    A A kg ( ) 8000 (0 8.0) 64000 N       f im v vpF A At t Pressure, 64000 64000 Pa = 64 kPa  F AP A A 10 C Redrawing the forces into a vector triangle Recognize it is a 6-8-10 right-angled triangle. (similar to a 3-4-5). Analysing the horizontal components in equilibrium: 6.0 cos 