1. If the linear momemtum of the body is increased by 50% the KE will be increased by
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
A spring is streched by 2cm, it's potential energy is U. If the spring is streched by 10cm its potential energy is
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 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