Posted by Ansermi on .
An elevator operates on a very slow hydraulic jack. Oil is pumped into a cylinder that contains the piston. The piston lifts the elevator as the internal cylinder pressure (P2) rises in comparison to the outside pressure (P1=101,325 Pa or about 14.7 psi). If the piston can lift 22 kN (about 5000 lb) a vertical distance of 6 m (about 20 ft) in 30 seconds then:
a. Calculate the output power of the piston while it is lifting its maximum load
b. If the efficiency of the piston is 0.9, what is the input power required?
c. What must be the maximum internal pressure (P2) if the total volume of oil required is 0.150 m^3?

Physics 
drwls,
a. Output Power = (weight lifted)(height lifted)/time
b. Input power = (Output power)/0.9
c. (P2  P1)*V = (input power)* time