Question

Two blocks, one 5.0 Kg and the other 2.0 Kg are suspended from a pulley such that the 5.0 Kg block is 4.0 m above the 2.0 Kg block and 5.0 m above the floor. The blocks are released from rest.
a. At the moment that the two blocks pass each other, what are their speeds?
b. Just before the 5.0 Kg block hits the floor, what are their speeds?
c. After the 5.0 Kg block hits the floor, the 2.0 Kg block keeps going up, how far does it go up?

Answer 1

a) the blocks have moved 2m.

Loss of GPE=gain of KE
5g2-2g2=1/2 (2+5)v^2 solve for v.
b. the blocks have moved 5 m
5g5-2g5=1/2 (2+5)v^2 solve for v.
c. the KE of the small block= change PE
1/2 2 v^2= 2 g h solve for h.