The collar has a weight of 8 lb. If it is released from rest at a height of h = 2 ft from the top of the uncompressed spring, determine the speed of the collar after it falls and compressed the spring 0.3 ft.

Answer 1

If the collar is a weight on top of the spring, use conservation of energy.

After falling h = 2 feet, the collar has velocity sqrt (2gh) = sqrt(2*32.2*2) = 11.35 ft/s.

The kinetic energy at that point can be set equal to the sum of the kinetic and potential spin energy, plus the loss of additional gravitational PE, after compressing the spring 0.3 ft. You will need the spring constant to compute the new velocity.