Answer
(a) 180 W (b) 6300 J
Work Step by Step
(a) To find the power, use the formula $$P=Fv$$ The force of friction is equal to $F=\mu_kmg$. Substituting this into the power equation yields $$P=\mu_kmgv$$ Substituting known values of $\mu_k=0.55$, $m=67kg$, $g=9.8m/s^2$, and $v=0.50m/s$ yields a power of $$P=(0.55)(67kg)(9.8m/s^2)(0.50m/s)=180W$$ To find the work done, use the relation that $$P=\frac{W}{\Delta t}$$ Solving for $W$ yields $$W=P\Delta t$$ Substituting known values of $P=180W$ and $\Delta t=35s$ yields a work of $$W=(180W)(35s)=6300J$$
