1. The problem statement, all variables and given/known data A spring of unstretched length l has a mass m with one end fixed to a rigid support. Assuming spring to be made of a uniform wire, the kinetic energy possessed by it if its free end is pulled with uniform velocity v is? 2. Relevant equations potential energy stored in a spring is 1/2kx^2 3. The attempt at a solution the free end is pulled by a velocity v but that is not constant through out,and it is the equivalent velocity that is to be considered.since kinetic energy changes with length,we can use integration to find the total kinetic energy,we can consider an element dm and find it's kinetic energy but i don't know what is the relation between velocity of the element and the distance of that element from rigid end.if this is know i can calculate the kinetic energy.