Question

2. A 20.0-kg block is connected to a 30.0-kg block by a
string that passes over a light frictionless pulley. The 30.0-
kg block is connected to a spring that has negligible mass
and a force constant of 250 N/m, as shown in the Figure.
The spring is upstretched when the system is as shown in
the figure, and the incline is frictionless. The 20.0-kg block
is pulled 20.0 cm down the incline (so that the 30.0-kg block
is 40.0 cm above the floor) and released from rest. Find the
speed of each block when the 30.0-kg block is 20.0 cm
above the floor (that is, when the spring is upstretched)