A ball of mass 1 kg is dropped from a tower. Find power of gravitational force at time `t=2s`. Take `g=10m//s^(2).
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At `t=2s,` velocity of the ball, `v=g t=10xx2=20m//s` . Gravitational force on the ball, `F=mg=1xx10=10N` , (downwards) `:.` Instantaneous power, `P=F.v=Fcostheta` `=(10)(20)cos0^@` `=200W`.
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