A bucket of sand with a mass of 24.5 kg is lifted using a fixed block, acting on the rope

A bucket of sand with a mass of 24.5 kg is lifted using a fixed block, acting on the rope with a force of 250 N. Calculate the efficiency of the installation.

The efficiency of a mechanism is defined as the ratio of useful work to the work done. Since a stationary block does not give a gain in strength or on the way, in order to lift the load to a height h, it is necessary to pull the rope to such a distance.
Useful work:
A1 = m * g * h;
Work done:
A2 = F * h;
Here
m = 24.5kg
g = 10m / s ^ 2 – acceleration of gravity,
F = 250H.
The efficiency is equal to:
k = (A1 / A2) * 100% = (m * g / F) * 100% = 98%.