Final answer:
The work done in lifting a 50 lb box a distance of 3 feet is 150 lb-ft.
Step-by-step explanation:
When calculating the work done in lifting an object, the formula Work = Force × Distance is applied. In this specific scenario, a 50 lb box is being lifted over a distance of 3 feet. The calculation involves multiplying the force (50 lb) by the distance (3 feet), resulting in 150 lb-ft of work. This relationship is based on the concept that 1 pound-force is equivalent to 1 lb-ft of work done per foot of displacement. Therefore, lifting the 50 lb box a distance of 3 feet results in a total work done of 150 lb-ft.