A motor is employed to raise a load straight upwards. The load has weight $W$. The motor gives a useful power output $P$. The load moves upwards at constant velocity $v$. Which expression shows the time needed for the motor to lift the load vertically upwards by a distance $d$?
- A$\frac{P}{Wd}$
- B$\frac{Wv}{P}$
- C$\frac{Wd}{P}$
- D$\frac{Pv}{W}$