12_SMSS 2010 Prelim P1 P2_Ans

Secondary 4 Express Paper 1 Paper 2 1 (a) ]1[s010.0t ]1[t)0.800(2 140.0 t)vu(2 1s = += += (b) ]1[s/m8000a ]1[)010.0(a00.80 atuv 2= += += 1 D 11 A 21 B 31 C 2 C 12 C 22 A 32 A 3 C 13 A 23 D 33 A 4 B 14 C 24 B 34 D 5 B 15 B 25 C 35 B 6 C 16 D 26 A 36 D 7 D 17 D 27 D 37 C 8 B 18 C 28 A 38 A 9 C 19 C 29 A 39 C 10 B 20 C 30 D 40 D PHYSICS 5058/01 & 02 St. Margaret’s Secondary School Preliminary Examinations 2010

2 0 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 0.22 t/s speed/ m/s 80 leaves bow hits target (c) 2 marks for correct shape graph with clearly labelled values 1 mark for correct labelling of graph (leaves bow & hits target) 1 mark for correct calculation of distance travelled by arrow during flight (0.40 m for acc portion; 15.6 m for the 80 m/s portion) 2 (a) Upward forces at A and B. [1] (b) W = mg = 10.8 x 10 = 108 N [1] (c) ⊥ distance of W from B = (70.0 cos 45°) - 12.0 = 37.5 cm [1] Taking moments about the B, ]1[N5.67F ]1[5.371080.60F ACMCM A A = ×=× = F B = 108 – 67.5 = 40.5 N [1] 3 (a) P = (120 x 1000 x 10) [1] = 1200000 Pa [1] (b) Pressure increases with depth [1] so a thicker base is needed to withstand the greater force per unit area at the base. [1] (c) (i) loss in GPE = gain in KE mgh = ½ mv 2 10 × 100 = ½ × v2 [1] v = 44.7 m/s [1]

3 (ii) Power generated = 3600 x 10 x 100 x 60% [1] = 3600000 x 60% = 2160000 W [1] 4 (a) The dust are kept in suspension as they are continuously hit by the air molecules/particles [1] which are at constant random motion and moving at high speeds. [1] (b) (i) As the gas is heated, the gas molecules gain K.E/speed up and hit the piston with a greater force and more often [1], hence pushing the piston outwards. (ii) As the piston moves outwards the volume of the gas increases and the rate of collision decreases, hence pressure decreases. [1] The piston stops moving when the pressure inside equals the pressure outside. [1] 5 (a) ]1[23r ]1[rsin 35sin47.1 rsin isinn °= = = (b) Both have the same refractive indices [1] therefore the speed of light does not change when it reaches the interf ace and no bending will be observed.[1] (c) (d) No. [1] The incident ray from air can only enter the corn oil at max. 90 °, this will give a refracted angle = critical angle of corn oil. [1] But for total internal reflection to occur, the incident angle at P needs to be greater than the critical angle of corn oil. [1] 6 (a) positive charges on the inside and negative charges on the outside of the can. (equal number must be drawn.) [1] 35° [1]

4 (b) The can will be positively charged. [1] The excess electrons will move from the can to the earth. [1]