A traditional physics textbook – both heavy and
expensive – is released from rest at position 1 above a spring. It falls and contacts the spring at position 2. The spring reaches maximum compression at position 3. suppose the textbook has a mass M and is dropped from a height y1 above the ground. The spring has a spring constant of k and an uncompressed length of y2. The book strikes the spring with a speed v2 at position 2; at position 3, the spring is compressed a distance d.