Differential force equations for two-mass spring-damper system

[erezb84]

Homework Statement

Hi,
i need to write the differencial force equation for the system attached,
and i am not sure if what i do is right.

when:
F- externa power
m1,m2 - mass
x1,x2 - mas location

The Attempt at a Solution

This is what i got:
for m1:
F-k*(x1-x2)-D*(x1'-x2')=m*x1''
for m2:
k*(x1-x2)+D*(x1'-x2')=m*x2'

what do you think?
thanks!

 

[LawrenceC]

Looks fine except you left of the double prime for acceleration on the second equation.

 

[erezb84]

ok, thanks!