19. Find the tension T for the system shown in figure :- T T T 1 kg 2 kg 3 kg (1) IgN (2) 2 gN (3) 5 gN (4) 6 gN 20. A ball of mass 0.5 kg moving with a velocity of 2 m/sec strikes a wall normally and bounces back with the same speed. If the time of contact between the ball and the wall is one millisecond, the average force exerted by the wall on the ball is (1) 2000 N (2) 1000 N (3) 5000 N (4) 125 N 21. Find normal reaction force by ground on 10 kg block: [g = 10 m/s] 2kg 3kg 5kg 10kg (1) 100 N (2) 150 N (3) 180 N (4) 200 N 22. A cricket ball of mass 150 g is moving with a velocity of 12 m/s and is hit by a bat. Duration of contact between the ball and the bat is 0.01 sec and average force exerted on the ball by the bat is 480 N. The velocity with which the ball turns back: (1) 12.032 m/s (3) 32 m/s (2) 20 m/s (4) 44 m/s 23. Three equal weights of mass 2 kg each are hanging on a string passing over a fixed pulley as shown in fig. What is the reaction of pulley on the support? (1) 28.6 N (3) 26.8 N A B C (2) 53.33 N (4) 19.6 N