(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

the hydraulic lift at a car repair shop is filled with oil. the car rests on a 25cm diameter piston. to lift the car, compressed air is used to push down on a 6cm diameterpiston. By how much must the air pressure force b eincreased to life the car 2.0m.

2. Relevant equations

DeltaF = pg(A1+A2)h where p is the density (900 for oil) and h is the height

3. The attempt at a solution

please read this: I didnt use the above equation because it was just stated in the text book with no logic, so i used another equation derived from the logic of previous pages. We know F1/A1 = F2/A2 to keep the car up without lifting it a certain height, and to lift it a certain height, the equation is F1/A1 = F2/A2 + pgh where p is density and h is height. these equation are given in the textbook as well and they make sense. so to find the change in pressure, dont you just arrange the two equations for F1 and subtract them? Why is this wrong!!!!!

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Huge problem on hydraulic lifts

**Physics Forums | Science Articles, Homework Help, Discussion**