Hydraulic problem, need help

1. Dec 13, 2004

foggy

hydraulic problem, need help!!!

a hydraulic chamber in which a spring (spring constant = 1456 N/m) is attached to the input piston, and a rock of mass 39.4 kg rests on the output plunger. The piston and plunger are at the same height, and each has a negligible mass. By how much is the spring compressed from its unstrained position?

output plunger=65cm^2
input plunger=15cm^2

i have no clue how to get it started, can anyone help!

2. Dec 13, 2004

thursdaytbs

Well you have the equation:
$$\frac{F_{1}}{A_{1}} = \frac{F_{2}}{A_{2}}$$

The output plunger has an Area of $$65cm^2$$ and a force downward of the rock (Mass*Gravitational Accelertaion = Force)

And you know the area of the input plunger.

Also, the force on the spring is $$F=kx$$

Solve using that information. Good luck.

3. Dec 13, 2004

foggy

thanks

thank you so much that really helped a whole lot.

-foggy