Question

A towboat pulls a ship with a horizontal force of 6.00⋅103N, moving the ship through the harbor 3.00km. If the boat does this in 15 min, how much power does the towboat use?

Answer 1

The towboat moves the ship by a distance
$d=3.00 km=3000 m$
so the work done by the towboat to move the ship is the product between the force applied and this distance:
$W=Fd=(6.0 \cdot 10^3 N)(3000 m)=1.8 \cdot 10^7 J$

The time taken for this process is
$t=15 min \cdot 60 s/min = 900 s$
So the power used by the twoboat is the ratio between the work done and the time taken
$P= \frac{W}{t}= \frac{1.8 \cdot 10^7 J}{900 s}=2.0 \cdot 10^4 W$