Question

A block and tackle is used to lift an engine that weighs 925 lb and is raised 1.5 ft. The operator pulls with a force of 150 lb over a distance of 10 ft. a. Calculate the input and output work. b. Calculate the efficiency of the block and tackle?

Answer 1

The input work of the block and tackle system is 1500 ft-lb, the output work is 1387.5 ft-lb, and the efficiency of the system is 92.5%.

Step-by-step explanation:

To calculate the input and output work of the block and tackle system, we can use the following formulas:

Input work = force x distance

Output work = weight x distance

In this case, the input work is 150 lb x 10 ft = 1500 ft-lb. The output work is 925 lb x 1.5 ft = 1387.5 ft-lb.

To calculate the efficiency of the block and tackle system, we can use the formula:

Efficiency = (output work / input work) x 100%

Substituting the values, we get efficiency = (1387.5 ft-lb / 1500 ft-lb) x 100% = 92.5%.