In a race, 20 balls are placed in a line at intervals of 4 meters, with the first ball 24 meters away from the starting point. A contestant is required to bring the balls back to the starting place one at a time. How far would the contestant run to bring back all balls?

A long a road lie an odd number of stones placed at intervals of 10 meters. These stones have to be assembled around the middle stone. A person can carry only one stone ar a time. A man started the job with one of the end stones by carrying them in succession. In carrying all the stones, the man covered a total distance of 3 kilometers. Then the total number of stones is

Two friends A and B (each weighing 40 kg ) are sitting on a frictionless platform some distance d apart. A rolls a ball of mass 4 kg on the platform towards B which B catches. Then B rolls the ball towards A and A catches it. The ball keeps on moving back and forth between A and B . The ball has a fixed speed of 5 m//s on the platform. a. Find the speed of A after he rolls the ball for the first time. b. Find the speed of A after he catches the ball for the first time. c. Find the speed of A and B after the ball has made five round trips and is held by A . d. How many times can A roll the ball? e. Where is the centre of mass of the system A + B + ball at. the end of the nth trip?

The benches of a gallery in a cricket stadium are 1 m wide and 1 m high. A batsman strikes the ball at a level one meter above the ground and hits a mammoth sixer. The ball starts at 35 m/s at an angle of 53^0 with the horizontal. The benches are perpendicular to the plane of motion and the first bench is 110 m from the batsman. On which bench will the ball hit?

A football ils kicked with a velocity of 20 m/s at an angle of 45^0 wilth the horizontal. A. Find the time taken by the ball to strike the ground. b.Find the maximum height it reaches. C. How far away from the kick dows it hit the ground? Take g=10 m/s^2 .

Two speakers S_(1) and S_(2) derived by the same amplifier and placed at y = 1.0 m and y = - 1.0 m (Fig . 7.9) The speakers vibrate in phase at 600 Hz . A man stands at a point on the x - axis at a very large distance from the origin and starts moving parallel to the Y - axis . The speed of sound in air is 330 m//s . (a). At what angle will the intensity of sound drop to a minimum for the first time ? (b) At what angle will the sound intensity be maximum for the first time ? (c ) If he continues to walk along the line , how many more maxima can he hear ?

A ball, intially at the top of the inclined hill, is allowed to roll down. At the bottom its speed is 4 m/s. Next the ball is again rolled down the hill, but this time it does not start from rest. It has an initial speed of 3 m/s. How fast is it going when it gets to the bottom ?