MJC_H1_PHY_P1_Answers

Meridian Junior College Solutions to H1 Prelim Paper 1 JC2 Preliminary Examinations 2016 2 Proposed solutions to H1 Physics Prelim Paper 1 1 B 16 C 2 B 17 B 3 D 18 B 4 C 19 A 5 D 20 A 6 B 21 B 7 C 22 D 8 D 23 C 9 C 24 D 10 D 25 C 11 D 26 B 12 D 27 A 13 C 28 C 14 A 29 A 15 A 30 A 1 Ans: (B) 2 21 F=BIL Fm aB= =IL IL kg m sBase unit of B A m kg s A      2 Ans: (B) A Both vectors B Magnetic flux density: vector, kinetic energy: scalar C Both scalars D Both scalars 3 Ans: (D) 0.5 0.01 2.0 1.89 2 (1s.f.)2.0 0.30 0.30 VR I RVI RVI R            

Meridian Junior College Solutions to H1 Prelim Paper 1 JC2 Preliminary Examinations 2016 3 4 Ans: C Let the total distance be S and the total time t. Since the stone falls 0.75S in the last two seconds of its fall, it travels 0.25S in the first (t-2) seconds. 2 22 22 1 (2 ) 0 . 2 5 S2 11 (2 ) 0 . 2 5 ( )22 (2 ) 0 . 2 5 20 . 5 4.0sec      gt gt g t tt tt t 5 Ans: D Since the stone takes 2.0 s to reach its highest point, at 4.0 s it will have reached the point of S = 0. Taking upwards as positive, Option A incorrect – Stone is on its upwards motion. The displacement and velocity is positive and the acceleration is negative. For option B and C, the stone is on its downwards motion but has not reach the point of S = 0. Hence displacement is positive, velocity and acceleration are negative. Option D correct – the stone is on its downward motion (having passed the point of S = 0) with negative displacement. Velocity and acceleration are negative. 6 Ans: B Total distance travelled = estimated area under the speed-time graph = 6 big squares = 10(20)6 = 1200 m Average speed = total distance travelled/ total time taken = 1200 m / 100 s =12 m s -1

Meridian Junior College Solutions to H1 Prelim Paper 1 JC2 Preliminary Examinations 2016 4 7 Ans: C 21 2 1 1 Using force diagram and resolving horizontally and vertically, sin30 (1) cos30 (2) (1) :t a n 3 0(2) (Alternative: Using vector triangle) tan30 15tan30 8.66 8.7 (2s.f.) NN NW N W NW      8 Ans: D When reading is more than F, means that upward force by spring balance on mass is greater than weight of mass. Net force upwards – acceleration directed upwards. 9 Ans: C The collision must be inelastic since a “loud sound” was produced (conversion of kinetic energy into sound energy). Option A: The carts may move in opposite directions even for an inelastic collision. Option B: Violates principle of conservation of momentum. Option D: This is only true if collision is elastic. 10 Ans: D Since particle Y is stationary (no KE nor momentum), Initial KE of system is E, initial momentum of system is p. Collision is inelastic – final kinetic energy of system should be less than E (Option C or D) Momentum of any collision must be c onserved, final momentum of system should be still p. Full working: Conserva