YIJC 2024 JC2 PRELIM H2 Phy P1 Soln

©YIJC 9749/01/YIJC/24 2024 YIJC JC2 Preliminary Exam H2 Physics Paper 1 Solution Question Answer Question Answer Question Answer 1 A 11 A 21 D 2 C 12 D 22 B 3 B 13 A 23 C 4 C 14 B 24 B 5 B 15 D 25 C 6 A 16 C 26 A 7 D 17 C 27 C 8 B 18 A 28 B 9 A 19 D 29 C 10 A 20 B 30 C MCQs Solutions Qn Answer Explanation 1 A Surface area of cylinder A = 2rL = 282.7 cm2 20.1 0.1 282.7 10 cm (to 1 s.f.)3.0 15.0 A r L A r L rLAA rL   =+     = + = + =       Therefore A = (280  10) cm2 2 C During free fall, 2 =+ = 0 + (-9.81)(1.0) = 9.81 m s v u at v v −− On hitting the sand, 22 23 32 2 0 ( 9.81) 2 (8.0 10 ) 6.0 10 m s v u as a a − − =+ = − +  =− 

©YIJC 9749/01/YIJC/24 2 3 B Considering car and trailer as a single system to find common acceleration -2 5600 1200 400 4000 N 4000 2.0 m s1500 500 net D car trailerF F f f a = − − = − − = == + Considering only the trailer: ( )500 2.0 1000 N 1000 400 1400 N net trailer net trailer F m a F T f T T = = = =− =− = 4 C Taking moments at P, force at Q must be upwards to balance the larger clockwise moment due to weight. Taking moments at Q, force at P must be downwards to balance the larger clockwise moment due to tension. 5 B ( )( )11 70 0.040 0.020 0.70 J22EPE Fx= = − = 6 A Component of the weight parallel to the slope = W sin30o = (1.0×103)(0.50) = 0.50×103 N Because the barrel is moving at constant v, the applied F = W sin30o WD = Fx = (0.50×103)(5.0) = 2500 J 7 D Useful WD in lifting the weight = (480)(3.5) = 1680 J WD by man in pulling rope = (200)(10.5) = 2100 J 1680Efficiency 100% 80%2100=  = 8 B period of sound wave, 1T f= ( ) 1 rad8 2200 864 rad s8 2 16 fT   − == = = = =  9 A Using 2 GMmKE R= and 2 GMmTE R=− , both satellites will have the same TE if their KE is equal. Hence A is false. Since KE is same, mass of satellite is proportional to R. So, if X has a larger mass, it will have a larger radius of orbit. Option B is valid. Kepler’s 3rd law would suggest that X has a larger period. Since angular velocity is inversely proportional to period, the former is smaller.

©YIJC 9749/01/YIJC/24 3 10 A Work done in moving from X to Z ( ) 1 100 120 20 J 20 2000 1980 J 990 J kg2.0 2.0 X Z X Y Y Z X X Z Z XX X W W W W W W WW → → → → → → −→ → = + = + − =− = + =− + = −= = =− 11 A ( )( ) ( )( )( ) ( )( ) 3 3 3 4 4 Heat supplied by kettle heat absorbed by water heat loss 1.2 10 30 60 0.80 4.2 10 100 25 0.80 2300 10 heat lo ss heat loss 6.8 10 J 6.8 10power loss 38 W30 60 =+   =  − +  + = ==  12 D ( ) ( ) ( ) ( ) ( ) ( ) 2 2 22 22 31 22 constant 330 120% 475 K rms rms rms rms initial final final rms rms final U NkT Nm c T c TT cc T cc T == =         =       =  = 13 A With damping, the amplitude will be lower for all frequencies due to loss in ene