$2.3.3.$ To test equipment under conditions of extreme acceleration and weightlessness, a container with it is tossed to a height of $125\text{ m}$ by a pneumatic piston device located at the bottom of a vacuum shaft. With what force does the piston act while tossing the container, if it extends by a length $h = 1\text{ m}$ in the process, and the mass of the container with the equipment is $m = 2\text{ t}$?
Solution
The piston device imparts a certain amount of kinetic energy to the equipment, which, according to the law of conservation of mechanical energy (since the shaft is a vacuum), converts into potential energy. Therefore, the work done by the force of the piston device is equal to the change in potential energy: $$Fh = mgH \implies F = mg\frac{H}{h}$$