A box that weighs 725 N is lifted a distance of 20.0 m straight up by a cable attached to a motor. The job is done in 6.5 s. What power is developed by the motor in watts and kilowatts?
P = FV = 725 * (20 m / 6.5 s. = 2231 W = 2.231 KW.
To find the power developed by the motor, we need to use the formula:
Power = Work / Time
First, let's find the work done on the box. Work is equal to the force applied on an object multiplied by the distance through which the force is applied. In this case, the force is the weight of the box, which is given as 725 N, and the distance is 20.0 m. So,
Work = Force * Distance
Work = 725 N * 20.0 m
Work = 14,500 N·m (or Joules)
Now, we can substitute the work and the time into the power formula:
Power = Work / Time
Power = 14,500 N·m / 6.5 s
To convert this answer to watts, divide by 1. To convert it to kilowatts, divide by 1,000.
Power (in watts) = 2,230.77 W
Power (in kilowatts) = 2.23 kW
Therefore, the power developed by the motor is approximately 2,230.77 watts or 2.23 kilowatts.