A vertical spring with a spring constant of 460 N/m is mounted
on the floor. From directly above the spring, which is unstrained,
a 0.26-kg block is dropped from rest. It collides with and sticks
to the spring, which is compressed by 3.8 cm in bringing the block
to a momentary halt. Assuming air resistance is negligible, from
what height above the compressed spring was the block dropped?