ST5.9 Spring Blocks
Two
4.0 kg blocks are tied together with a compressed spring between
them. They are thrown from the ground with an initial velocity of
35 ms-1,
45∘ above the horizontal. At the highest point of
the trajectory they become untied and spring apart. About how far below
the highest point is the centre of mass of the two-block system
2.0 s
later, before either fragment has hit the ground?