Physics

Problem

4.0\,\text{kg}

crate is pushed along a horizontal surface by a constant horizontal force of

30\,\text{N}

. The coefficient of kinetic friction between the crate and the surface is

0.25

. The crate starts from rest. What is the instantaneous net power delivered to the crate after

3.0\,\text{s}

of pushing? (Use

g = 9.8\,\text{m/s}^{2}

.) a)

9.1\times10^{2}\,\text{W}

3.1\times10^{2}\,\text{W}

1.5\times10^{2}\,\text{W}

4.5\times10^{2}\,\text{W}