Question

A child pushes horizontally on a box of mass m which moves with constant speed v across a horizontal floor. The coefficient of friction between the box and the floor is μ. At what rate does the child do work on the box?

Answer 1

Answer:

Explanation:

Given

mass of box is m

speed of box is v

coefficient of friction $\mu =\frac{1}{4}=0.25$

Box is moving at a constant speed i.e. Net Force on box is zero

i.e. Frictional Force and Force Applied are Equal

$F=f_r=\mu mg$

The Rate at which power is generated is

$P=F\cdot v$

$P=\mu mg\cdot v$

$P=0.25mgv$