Engineering
Physics
Collision
Question

A piece of wood of mass 0.03 kg is dropped from the top of a 100 m height building. At the same time, a bullet of mass 0.02 kg is fired vertically upward, with a velocity 100 ms–1, from the ground. The bullet gets embedded in the wood. Then the maximum height to which the combined system reaches above the top of the building before falling below is : (g = 10 ms–2)

40 m

20 m

10 m

30 m

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Solution

Tcm From ground =0.03×1000.05=60  m

Vcm=0.02×1000.05=40  m

H=Vcm22g=40×4020=80 m

Height above building = 80 – 40 = 40 m