2022 9749 H2 Physics P1 MS EJC Suggested Solutions

©EJC 2022 9749/H2 PHYSICS 2022 PHYSICS SUGGESTED MARK SCHEME Maximum Mark: 190 9749 October/November 2022 Paper 1 Multiple Choice Question Key Question Key Question Key 1 A 6 C 11 A 2 C 7 B 12 C 3 B 8 C 13 B 4 B 9 C 14 C 5 D 10 D 15 A 16 D 21 D 26 A 17 B 22 B 27 B 18 B 23 C 28 A 19 A 24 D 29 C 20 A 25 B 30 C 1 Since vectors are initially in opposite directions, the initial (X − Y) yields the largest magnitude, eliminate B and D 180∘ means that Y is rotated half-round only, where magnitude of (X − Y) will not return to original value. 2 took 1 sec for vertical component of velocity to be zero ( ) ( )( ) 1 1 1 50 50 m s . 9 1 m s . 0 9.81 t 1 9 81 .81 5 an tn 11 1 0a xy xx x x yy yy y x u uu u t s su t at at u u v uv u  − − − = = = =+ = − =  + == = =  = −− =

2 ©EJC 2022 9749/H2 PHYSICS 2022 3 by conservation of linear momentum ( ) ( ) ( ) ( ) ( ) ( ) 1 e 5 l 2 a 0 s . t 2 i . c 05 2.5 _____ 1 0.5 2 0 1.5 5 3 o so m s fr m 1 : P p Q Q P Q Q Q Q QP Q v v v m m m mm v vm m − + = − + − = −= = = = − 4 consider free body diagram of buoy: ( ) ( ) ( ) ( ) water submerged 3141030 0.5 200 9.8123 683 N U W T T U W V g mg    − =+ = − = − =   = 5 consider free body diagram of mass in translational equilibrium: ( ) ( )( ) ( ) ( )( ) ( ) ( ) horizontally: sin 36 25 0.06 vertically: cos 36 25 0.06 cos 36sin 36 2.06 N T kx TW W  = = =  =  = 6 mean density so assume earth is uniform sphere: ( )( ) 2 3 6 11 3 9.81 44 33 4 3 4 6.37 10 6.67 103 5512 kg m GMg g G r g r rG r MG      − − = == = =  = 7 by conservation of energy, loss of GPE = work done against air resistance: ( ) ( ) ( )( )( ) 02 0.2 0.2 loss in GPE 0.6 0.6e 0.4 9.81 0.6 1 e 0.427 J 2n mg h h mg − − =− =− − = = = T W Upthrust T W Fspring 36∘

3 ©EJC 2022 9749/H2 PHYSICS 2022 8 all points along a radius have the same angular speed (the linear speed of the point on the circumference is the max and the linear speed at the centre is zero) 9 Eliminate A and B as all geostationary satellites, regardless of their mass, has to be at a fixed distance away from centre of Earth Eliminate D, the satellite will have the same angular velocity as the point on Earth’s surface directly below them but the satellite will have far more linear velocity (see reasoning in Q8) 10 gravitational potential is a scalar sum so: ( )   P due to M due to 4M 2 10 2 4 142 GMGM GM GM dd dd   =+         +     =−          −= − −=+ 11 ideal gas so internal energy is purely KE and is directly proportional to thermodynamic temperature: ( ) new new old old 2 new new 2 oldold new new old old 1 KE KE 160 2 80 273.15 73.15350 388 m s c c c T c T T T T T − = = += = = + 12 ideal gas so internal energy is purely KE and is directly proportional to thermodynamic temperat