Power is the rate at which energy is transferred or work is done. One watt means one joule transferred per second. Use P = E/t or P = W/t; convert minutes to seconds and kilowatts to watts. Example: A motor transfers 18 kJ in 2 minutes. Calculate power. 18 kJ = 18 000 J and 2 min = 120 s; P = 18 000/120 = 150 W. Use the stated equation and consistent units to obtain a numerical result, then check whether its size and direction fit the physical situation. Explain the result. Check your reasoning.