A jack requires 808 J of work to be done in raising a load, and ideally would do this amount of useful work. However, internal friction reduces the jack’s efficiency to 0.625. How much useful work is done by the jack?

Amass weighing 24 pounds, attached to the end of a spring, stretches it 4 inches. initially, the mass is released from rest from a point 8 inches below the equilibrium position. find the equation of motion. (use g = 32 ft/s2 for the acceleration due to gravity.)