A boy throws a rubber ball vertically upwards. What kind of work is done. By the force applied by the boy. Support your answer with reason.

What will you do to prevent leaf fall and fruit drop in plants? Support your answer with reason.

A boy of mass 40 kg climbs vertically upwards on a coconut tree to a height of 10m. Calculate the work done by the boy.

What is the work done by the force of gravity on a satellite moving round the earth ? Justify your answer.

A pebble of mass 0.07 kg is thrown vertically upwards. Give the direction and magnitude of the net force on the pebble:- at the highest point where it is momentarily at rest. Do your answers change if the pebble was thrown at an angle of 45^@ with the horizontal direction? Ignore air resistance.

A boy travelling in an open car moving on a levelled road with constant speed tosses a ball vertically up in the air and catches it back. Sketch the motion of the ball as observed by a boy standing on the footpath . Give explanation to support your diagram.

A ball of mass 100 g moving with a velocity of 10ms^-1 is stopped by a boy in 0.25sec. Calculate the force applied by the boy to stop the ball.