How much momentum will a dumb-bell of mass 10 kg transfer to the floor if it falls from a height of 80 cm and does not rebound? Take its downward acceleration to be 10ms−2
A
40kgms−1
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B
20kgms−1
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C
80kgms−1
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D
120kgms−1
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Solution
The correct option is A40kgms−1 Mass of dumb-bell, m=10kg; initial velocity, u=0; final velocity, v=?; distance, s=80cm=0.8m; acceleration, a=10ms−2 We know v2−u2=2as v2−(0)2=2×10×0.8 v2=16 v=√16=4ms−1 ∴ Momentum of dumb-bell transferred to ground =mv=10×4=40kgms−1