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?
Incorrect
Correct
Incorrect
Incorrect
Incorrect

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