In the example, what are the units used to express the calculated work?

In the example, what are the units used to express the calculated work?

• A. Newtons-Meters
• B. Foot-Pounds
• C. Joules
• D. Watt-Hours

Answer: (B)

Work is found by multiplying a force by the distance it moves. When the force is in pounds and the distance is in feet, the product is expressed in foot-pounds. Since the example uses imperial units (pounds and feet), the calculated work is given in foot-pounds. In contrast, Newton-meters would be the SI counterpart, and joules are the SI unit of work, but the problem’s units are imperial, so foot-pounds is the natural label. Watt-hours measure energy over time (often electrical energy), which isn’t the direct mechanical work of a single force through a distance.

Work is found by multiplying a force by the distance it moves. When the force is in pounds and the distance is in feet, the product is expressed in foot-pounds. Since the example uses imperial units (pounds and feet), the calculated work is given in foot-pounds. In contrast, Newton-meters would be the SI counterpart, and joules are the SI unit of work, but the problem’s units are imperial, so foot-pounds is the natural label. Watt-hours measure energy over time (often electrical energy), which isn’t the direct mechanical work of a single force through a distance.