Q4) A block of mass m hits a spring with a spring constant of k at x=0 as shown in the figure below. The maximum compression of the spring is D. The coefficient of friction is non-uniform and given by = Be-ax where and a are positive constants. Find a) The speed of the block, vo as it hits the spring b) The speed of the block, vr, when it comes back to x = 0 again, m www x=0