Part 1/4
a massless spring with force constant
502 n/m is fastened at its left end to a vertical
wall, as shown below.
(picture 1)
the acceleration of gravity is 9.8 m/s^2
initially, the 8 kg block and 4 kg block rest
on a horizontal surface with the 8 kg block in
contact with the spring (but not compressing it) and with the 4 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
0.2 m, and held in place while the 4 kg block
remains at rest as shown below.
(picture two)
determine the elastic energy u stored in
the compressed spring.
answer in units of j.

part 2/4
the 8 kg block is then released and accelerates
to the right, toward the 4 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 4 kg block.
answer in units of m/s.

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

part 4/4
find the horizontal distance the blocks move
before coming to rest.
answer in units of m.