A block of mass m is moving with a constant acceleration a on a rough horizontal plane. If the coefficient of friction between the block and ground is μ, the power delivered by the external agent after a time t from the beginning is equal to

Q:A block of mass m is moving with a constant acceleration a on a rough horizontal plane. If the coefficient of friction between the block and ground is μ, the power delivered by the external agent after a time t from the beginning is equal to
(A) ma2t
(B) μmgat
(C) μm(a+μg)gt
(D ) m(a+μg)at
Sol: Instantaneous power delivered = P = F.v = F v
where, F – f = ma
 F = f + ma
 P = (f + ma) v
Put f = μmg
 P = ( μmg + ma)v = m(a + μg).at

Author: Rajesh Jha

QuantumStudy.com for CBSE|IIT-JEE|NEET

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