An ore car of mass 37000 kg starts from rest
and rolls downhill on tracks from a mine. At
the end of the tracks, 9.9 m lower vertically,
is a horizontally situated spring with constant
3.9 × 10
5
N/m.
The acceleration of gravity is 9.8 m/s
2
.
Ignore friction.
How much is the spring compressed in stopping the ore car?
Answer in units of m