Q: A neutron travelling with a velocity v and K.E. ‘E’ collides perfectly elastically head on with nucleus of an atom of mass number A at rest. The fraction of total energy retained by the neutron is :
A bullet is fired at a target with a velocity of 80 m/s and penetrates 50 cm into it. If this bullet were fired into a target 25 cm thick with equal velocity, with what velocity would it emerge, supposing the resistance is uniform and same in both the cases?
Q: A child on a swing is 1 metre above the ground at the lowest point and 2 metre above the ground at the highest point. The horizontal speed of the child at the lowest point of the swing is (g = 10 m/s2 ) :
Q: A ball is allowed to fall down with initial speed v from a height of 10 m. It loses 50% kinetic energy after striking the floor. It reaches to the same height after collision. What is the value of v ?
(a) 28 m/s
(b) 7 m/s
(c) 14 m/s
(d) it is never possible
To reach same height of 10 m after collision,
Velocity After collision
As energy lost in collision is 50% , velocity becomes v⁄√2
Q: A ball of mass ‘m’ moving with a horizontal velocity ‘v’ strikes the bob of mass ‘m’ of a pendulum at rest. During this collision, the ball sticks with the bob of the pendulum. The height to which the combined mass raises is (g = acceleration due to gravity)