what is the efficiency of a pulley if 5000 joules of energy results in 3000 joules of work
Efficiency is defined as the ratio of useful output work to the input energy.
In this case, the useful output work is 3000 joules, and the input energy is 5000 joules.
Therefore, the efficiency of the pulley is calculated as:
Efficiency = (Useful output work / Input energy) * 100
= (3000 / 5000) * 100
= 0.6 * 100
= 60%
So, the efficiency of the pulley is 60%.