Posted by Akbar on .
In a hydraulic lift, the radii of the pistons are 2.93 cm and 10.1 cm. A car weighing W = 11.0 kN is to be lifted by the force of the large piston.
(a) What force Fa must be applied to the small piston? N
(b) When the small piston is pushed in by 10.4 cm, how far is the car lifted?
mm
(c) Find the mechanical advantage of the lift, which is the ratio W / Fa.
I really don't understand how to do this please explain step for step how to do this! I would really appreciate it, thank you.

Physics 
Elena,
a.
F1/A1 =F2/A2,
A =πR^2,
Fa = W•(r/R)^2 = 11000•(2.93/10.1)^2 = =925.7 N
b.
h2 = h1•(A1/A2) = h1•(r/R) = 3.02 cm
b.
MA = W/Fa = 11000/925.7 =11.9 
Physics to Elena 
Akbar,
Thanks for your help, I really appreciate it! The only thing I was wondering about is part b) it says its wrong i know it's 3.02 cm, but the answer has to be in mm i got that that would be 30.2 mm, but still its wrong can you please say why I am getting it wrong?