Please help! Donnie is working on his car and uses a pulley system that can lift a 1250 N engine up to a height of 2 m by exerting a force of 250 N. How much rope would Donnie need to pull?

Oxygen undergoes an isentropic expansion from 120 degree c and 280 kpa absolute to 140 kpa absolute. determine the final temperature of the oxygen and the amount of work per kg of o_2 produced in the process if it is adiabatic.