DHS 2021 JC1 MYE Physics (Solutions)

DUNMAN HIGH SCHOOL 2021 PHYSICS H2 (YEAR 5) 1 Answers to Mid-Y ear Exam Section A 1 2 3 4 5 6 7 8 9 10 B B B C B C A A B C 11 12 13 14 15 D D D C A 1 B Airbus A330: 870 km h−1 Boeing 737-300: 780 km h−1 2 B Let the top mark be and lower mark be . Let the time the ball passes the top mark be and when it passes the lower mark, . 270Hence the speed of the ball is 2.00 a b ba b ab t t bavv tt ttv ba v ba −= = − ∆ +∆∆ ∆ +∆= + − 2 mm 0.04 s 2 0.04 270 mm 2.00 s 270 2.00 a batt = += +− 3 B The gradient of the displacement-time graph gives the velocity. Car M is accelerating as it has an increasing velocity (since gradient increases). Car N is not accelerating as it has a constant velocity (since gradient is constant). Statement is incorrect. 4 C 2 2 1 2 1 0.5 For 1st half, 0.5 0.5 --- (1) For entire journey, 0.5 --- (2) Solve (1) and (2) 0.71 s ut at L at L aT tT = + = = = 5 B By Newton’s 3 rd Law of Motion, action and reaction forces are equal in magnitude and opposite in direction and they act on different bodies.

DUNMAN HIGH SCHOOL 2021 PHYSICS H2 (YEAR 5) 2 6 C 7 A 8 A Since all cuboids are fully submerged, volume of displaced water is the volume of cuboid which is the same for all cuboids. Since upthrust is the volume displaced water x density of water x g, upthrust is the same on all cuboids. 9 B Gain in GPE = 400 x 9.81 x 1200 = 4.7 MJ Power output = Work/time = 4.7 x 10 6 / 120 = 39kW Power input = 39/0.8 = 49kW From Newton’s 2nd Law of Motion, T – mg = ma (1) Mg sinθ – T = Ma (2) Adding the equations gives Mg sinθ – mg = (m + M)a Since the right hand side is positive, then Mg sinθ – mg > 0 or sinθ > m/M a a T Mg sinθ T mg extension e spring length/ cm 3 0 The corresponding extension of spring is shown on graph. From graph, spring constant k = F/e = 5/3 N cm-1 When force = 7 N, F = ke 7 = (5/3) e so extension e = 4.2 cm

DUNMAN HIGH SCHOOL 2021 PHYSICS H2 (YEAR 5) 3 10 C Since body is moving up the track with constant velocity, there is no change in its K.E. power supplied = rate of increase in G.P.E. + rate at which work is done against the resistive forces ( ) ( )( ) ( )70 9.81 20sin30 120 20 9267 9300 W mg h Fd tt ∆= + = °+ = = 11 D ( ) 22 1 1 2 2 2 minimum tension occurs at the top: 5.00.30 12.5 N0.60 9.6 N maximum tension occurs at the bottom: 12.5 15.4 N vTWm r T vTWm r T += = = ⇒= −= = ⇒= 12 D mE 22 Smm SE Sm 2 S force on the Earth due to the Moon for