A motor is employed to raise a load of $40\,\text{N}$. The motor has a power of $40\,\text{W}$, and the system is $20\%$ efficient. How much time is needed for the motor to lift the load by $0.50\,\text{m}$?
- A$0.50\,\text{s}$
- B$2.5\,\text{s}$
- C$5.0\,\text{s}$
- D$25\,\text{s}$