A massless spring with force constant 604 N/m is fastened at its left end to a vertical
wall, as shown below.
The acceleration of gravity is 9.8 m/s2
8 kg 5 kg
604 N/m
Initially, the 8 kg block and 5 kg block rest
on a horizontal surface with the 8 kg block in
contact with the spring (but not compressing
it) and with the 5 kg block in contact with the
8 kg block. The 8 kg block is then moved to
the left, compressing the spring a distance of
0.6 m, and held in place while the 5 kg block
remains at rest as shown below.
8 kg 5 kg
k 0.6 m
Determine the elastic energy U stored in
the compressed spring.
Answer in units of J.

(part 2 of 4)
The 8 kg block is then released and accelerates
to the right, toward the 5 kg block. The
surface is rough and the coefficient of friction
between each block and the surface is 0.5 . The
two blocks collide, stick together, and move
to the right. Remember that the spring is not
attached to the 8 kg block.
Find the speed of the 8 kg block just before
it collides with the 5 kg block.
Answer in units of m/s.

(part 3 of 4)
Find the final speed of both blocks (stuck
together) just after they collide.
Answer in units of m/s.

(part 4 of 4)
Find the horizontal distance the blocks move
before coming to rest.
Answer in units of m.