A bucket of sand with a mass of 24.5 was raised using a fixed block not 10 m high

A bucket of sand with a mass of 24.5 was raised using a fixed block not 10 m high, acting on the rope with a force of 250N. Calculate the efficiency of the installation.

Let us find the perfect work Ac, if a bucket of sand with a mass of m = 24.5 kg was lifted with the help of a stationary block to a height of H = 10 m:
Ac = m * g * H = 24.5 * 10 * 10 = 2450 J.
Let us find the expended work Az, if a force F = 250 H was applied to raise the bucket:
Az = F * H = 250 * 10 = 2500 J.
Let’s find the efficiency of the block:
Efficiency = Ac * 100% / Az = 245000/2500 = 98%.
Answer: The efficiency of the fixed block is 98%.