A man has a choice of using either an escalator or a lift to move upwards between two floors in a hotel. The escalator takes $20\,\text{s}$ to transport the man from one floor to the other. The useful work done against gravity is $W$. The useful power developed is $P$. The lift takes $30\,\text{s}$ to transport the same man between the same two floors. What useful work against gravity is done by the lift, and what useful power is developed by the lift?
- Auseful work done against gravity by lift: more than $W$; useful power developed by lift: less than $P$
- Buseful work done against gravity by lift: more than $W$; useful power developed by lift: $P$
- Cuseful work done against gravity by lift: $W$; useful power developed by lift: less than $P$
- Duseful work done against gravity by lift: $W$; useful power developed by lift: $P$