EJC 2022 Prelim P1 Guide

©EJC 2022 9749/J2H2Prelim/2022 EUNOIA JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATIONS 2022 General Certificate of Education Advanced Level Higher 2 PHYSICS MARK SCHEME 9749 Aug/Sep 2022 Paper 1 Multiple Choice Question Key Question Key Question Key 1 B 6 D 11 B 2 A 7 C 12 A 3 C 8 B 13 D 4 C 9 D 14 C 5 A 10 C 15 D 16 D 21 A 26 A 17 A 22 B 27 A 18 B 23 D 28 C 19 D 24 A 29 D 20 C 25 D 30 B 1 mass of electron negligible compared to nucleons question similar to asking for nuclear density: material nucleus mas 4s V = 4 u 3  3 nucleus 27 18 3 4510 10 10 kg m r − − −= 2 0.22EtRs     =  0.22 units of units of kg m EtsR  − =  =   22 m s − ( ) ( ) 2s kg ( ) ( ) 0.2 3 0.25 m m m dimensionless1 − − −    =  = 3 constant acceleration so ( ) 2 1 0 1 22 9 81 3 202 15 7 m s gs ut at t . . u. tu u − =+ −=+ − = =+ 4 upthrust depends on weight of fluid displaced so need to displace a greater volume of fluid, increase either x or z 5 each spring supports 4 N; area under force-extension graph up till 4 N: ( )( ) 21 3 10 4 0.060 J2 −= 6 a counter example is friction between tyres exists, but does not reduce total energy when there is no slippage even as vehicle (the machine) does work (increase KE)

2 ©EJC 2022 9749/J2H2Prelim/2022 7 apply knowledge from Newton’s cradle that transfer of KE between 2 masses is 100% if masses are equal and one mass is initially stationary we model the system as separated blocks doing elastic collisions, take right +ve: consider A and B only: PCLM: relative spe 1ed 0 : 0 A A A A B B BA u m m v mmvv v + = + =− ( )10 m= 4Avm+( )( ) 1 1 10 6m 1 3 5 s 10 4 5 m s 40 0 0 A A A BA v v v vv − − = + =− + + =− = = so A will move left. B will undergo newton’s cradle style collision until E moves to hit F consider E and F only PCLM: relative spee 0 d 4 : 4 E E E E F FE Fum m m v v v v m − + = + = ( )( )44 m=( ) Evm+ ( ) 1 1 12 2.4 3 4 16 m s5 2 6.4 m s 54 5 E E E F v v v v − − =+ + = = + + == so both E and F moves to the right. that leaves B, C and D at rest. 8 sketch in order visualize friction pivot at wall F W W N L N W = = ( ) cos friction2 L +  ( ) sin F LN  = ( ) cos tan2 tan 2 FW WF W N WNN N    = − += A B C D E F W NF NW friction

3 ©EJC 2022 9749/J2H2Prelim/2022 9 tension in string 1 provides centripetal force for 3 masses so must be largest magnitude; eliminate A and C centre of mass of 3 separate masses is at centre i.e. mass 2 so tension in string 1 is equivalent to a string providing centripetal force to a mass of 3m at radius 2r: ( )( ) ( ) 2 1 2 3 1 3 32 3 2 T m r T m r T T   = = = eliminate B or via considering free bodies: T3 provides centripetal force on outer mass ( ) 2 33m r T  =