A block of mass m moving at a velocity v collides with another block of mass 2m at rest. The lighter block comes to rest after collision. Find the coefficient of restitution.
A small mass attached to a string rotates on a frictionless table top as shown. If the tension on the string is increased by pulling the string causing the radius of the circular motion to decrease by a factor of 2, the kinetic energy of the mass will
(a) Increase by a factor of 4 (b) Decrease by a factor of 2
(c) Remain constant (d) Increase by a factor of 2