2017 RI H2 Physics P2 solutions

2017 Year 6 H2 Physics Prelim Paper 2 Mark Scheme 1 (a) Acceleration is defined as the rate of change of velocity with respect to time. [B1] (b) (i)  1 sin 9.0 ( 9.81 sin26 )(0.70) 5.99 6.0 m s (2 s.f.) vu g t         [M1] [A0] (ii) By the principle of conservation of energy, 22 22 22 gain in GPE loss in KE 1 ()2 2 (9.0) (6.0) 2(9.81) 2.29 2.3 m ( 2.s.f) mgh m u v uvh g      [M1] [A1] (c) (i) y y y 1 tan5.0 6.0 cos26 (tan5.0 )(6.0cos26 ) 0.472 0.47 m s v v v v         x [M1] [A0] (ii) 22 yy y 22 yy 22 2 2 (0.47) (6.0 sin26 ) 2( 9.81) 0.341 0.34 m y vu a s vus a       [M1] [A1] (ii) The momentum of the sphere is not conserved during the collisi on because there is a net force acting on it due to the contact force by t he ceiling and the gravitational force on it by the Earth. [B1] (d) Linear displacement up the slope (must use ruler). Shape of 2 disjointed parabolas (peak must be obvious). [B1] [B1] y/m 0 2.3 x/m 2.64 5 Vx Vy V

2 © Raffles Institution 9749/02 2 (a) Vector quantities have magnitude and direction, whereas scalar quantities only have magnitude. [B1] (b) (i) Drawn to scale, where vi = initial velocity vf = final velocity v = the change in velocity = vf – vi Directions and labels of all vectors are correct. Length of v is correct (accept 4.5 – 4.8 cm) [B1] [B1] (ii) Using cosine rule, Using scale drawing, 22 if i f 22 1 1 1 1 2 ave 2 cos 4.6 cm 50.0 65.0 2 50.0 65.0cos45 46 km h 46.1 km h 12.8 m s 12.8 m s 12.8 0.427 m s30 vv v v v v va t                     [M1] [A1] (c) (i) 12 i 1f 2 25.0 30.050.0 65.060 60 53.33 53.3 km (3 s.f.)     ss v tv t [A1] (ii) 1i 1 1i 1 1i 1 i1 1i 1 i 1 i 1 i1 2f 2 f 2 f 2 12 i 1 ,where 25.0 0.5( ) ( ) 0.5 50.0 60 60 0.208 0.416 0.625 km 30.0 0.5() () () 0 . 5 6 5 . 0 60 60 0.250 0.542 0.792 km ()                         sv t sv tsv t vtsv t v t v tvt sv t v t v t ss v t f2() 0.625 0.792 1.417 1 km (1 s.f.)   vt OR [M1] [M1] [A1] OR N v vi vf v vi

3 © Raffles Institution 9749/02 max min max min 25.5 30.550.5 65.5 54.758 km60 60 24.5 29.549.5 64.5 51.925 km60 60 54.758 51.925 1.417 1 km22        s s sss [M1] [M1] [A1] (iii) Total distance 53 1 km (both values have the same precision) [B1] 3 (a) The principle of conservation of momentum states that the total momentum of a system remains constant, provided no net external force acts on it. [B1] [B1] (b) (i) Taking the velocity to the right as positive. (Statement must be written.) By the principle of conservation of momentum, XX YY X Y