2024 ACJC J2 H1 Physics Prelim P1 AS

Anglo-Chinese Junior College 2024 J2 Preliminary Exam Paper 1 Guide H1 (8867) Physics JC2 2024 Page 1 of 5 Qn Ans Discussion 1 C base units of P = base units of ( A v n) (kg m s2)(m s1) = (kg m3)(m2)( m s1)n kg m2 s3 = kg m3+2+n sn Comparing the indices for s, n = 3 2 D Density 3 3 where m V r dV    Δ Δ Δ 100% 3 100% 0.1 0.043 100%32.5 1.87 6.7% m d m d                           3 C o o o o 15cos20 6.0 sin40 17.95 18.0 N 15sin20 6.0cos 40 0.5340 0.534 N x y F F         4 B At highest point, vertical component of the velocity is zero. Hence the ratio is sin sinv v   . 5 A Option A – Non-linear gradient indicates largest change in velocity with time Option B – Almost constant gradient indicates almost constant velocity with no acceleration. Option C – Constant gradient indicates constant velocity with no acceleration Option D – Zero velocity 6 D 2 2 2 2 1 2 2 2 1 1 2 2 ( ) Using sin , 2 ( )sin s ut at ha t t g a hg t t          7 B When the bucket is moving at uniform speed, 0T mg T mg    When the bucket is decelerating uniformly,   ' ' mg T ma T m g a vm g t          Difference in tension = T’  T vm g mgt mv t       

Anglo-Chinese Junior College 2024 J2 Preliminary Exam Paper 1 Guide H1 (8867) Physics JC2 2024 Page 2 of 5 8 A 2 2 2 2 2 2 2 ( )Rate of change of momentum ( vol of water expelled) ( ) 1000 0.012 10 45 N rel rel rel mv t mv t v t r hv t hv r t v r v r v                    9 C Assume Charlie throws the ball to the right and take rightwards as positive. Consider Charlie and the ball as 1 system, Before throwing the ball,   before throw after throw 1 0 0 (1.5)(2.5) (60)( ) 0.0625 m s ball ball Charlie Charlie Charlie Charlie p p m u m u u u         Charlie is moving to the left with speed 0.0625 m s1 after throwing the ball. Consider the returning ball and Charlie as 1 system now, before catch after catch after catch 1 after catch (60)( 0.0626) (1.5)( 2.5) (61.5)( ) 0.122 m s p p v v        10 D A collision is elastic if relative speed of approach equals relative speed of separation. 1 2 2 1 1 2 2 1 ( )u u v v u u v v        Options A and B are wrong. An elastic collision is also one in which K.E. is conserved. total initial K.E. of system = total final K.E. of system 2 2 2 2 1 2 1 2 2 2 2 2 1 2 1 2 1 1 1 1 2 2 2 2mu mu mv mv u u v v       11 C cos18 520 550 Ncos18 T W T 