A body of mass 1kg is thrown vertically upwards with initial KE of 98J. The hieght at which it is reduced to half will be
A spring is streched by 2cm, it's potential energy is U. If the spring is streched by 10cm its potential energy is
An electric motor pumps 75 litres of water pre second to a hieght of 5m. If it consumes a power of 5 kw, its efficiency is
1. If the linear momemtum of the body is increased by 50% the KE will be increased by
A chain of mass m is placed on a smooth table with 1/7th part of its length l hanging over the edge. The workdone in pulling the chain back to the surface of the table is
If the length of the barrel of a rifle is cut by 5cm, the speed of the bullet reduces from 21m/s to 19m/s. if the mass of the bullet is 50gm, then the force acting on the bullet is
A ball falling freely from a hieght of 4.9m strikes a horizontal plane. If the coefficient of restitution is 3/4, the ball will strike the plane again after
A body of mass 5kg strikes another body of mass 2.5kg initially at rest. The bodies after collision coalesce and begin to move as a whole with a kinetic energy of 5J. The KE of the first body before collision is
What power a sprinter must develop from the start if has to impart his body (m=65kg) a speed of 9m/s in 3s
An electric motor winds a cable of tension 4500N at the rate of 2 m/s. Its power is