Question

The velocity ratio of a pulley system is 2. If its efficiency is 75%, what is its mechanical advantage? If the load is 120 N, what is the size of the effort? What work is done by the effort if the load is lifted 0.5 m? How much energy is wasted?

A. 0.5, 160 N, 80 J, 20 J
B. 1, 120 N, 60 J, 30 J
C. 2, 60 N, 30 J, 60 J
D. 1.5, 80 N, 40 J, 20 J

Answer 1

The mechanical advantage of the pulley system is 2, the size of the effort is 60 N, the work done by the effort is 30 J, and the energy wasted is 7.5 J.

Step-by-step explanation:

To find the mechanical advantage of the pulley system, you can use the formula MA = Load/Effort. Since the velocity ratio is given as 2, the mechanical advantage must also be 2. Therefore, the mechanical advantage is 2.

To find the size of the effort, you can use the formula Effort = Load/MA. Substituting the given values, we get Effort = 120 N / 2 = 60 N.

To find the work done by the effort, you can use the formula Work = Effort x Distance. Substituting the given values, we get Work = 60 N x 0.5 m = 30 J.

Finally, to find the energy wasted, you can use the formula Energy Wasted = Work - Useful Work. The efficiency of the pulley system is given as 75%, which means the useful work is 75% of the total work. Substituting the given values, we get Energy Wasted = 30 J - (0.75 x 30 J) = 7.5 J.