Question

K constant= 347.454
Now, three masses m1 = 3.9 kg, m2 = 11.7 kg and m3 = 7.8 kg hang from three identical springs in a motionless elevator. The springs all have the same spring constant that you just calculated above.
Now the elevator is moving downward with a velocity of v = -2 m/s but accelerating upward with an acceleration of a = 5.2 m/s2. (Note: an upward acceleration when the elevator is moving down means the elevator is slowing down.)
What is the force the bottom spring exerts on the bottom mass?

I think I may be able to solve this question if I could figure out how to get a.

Answer 1

I don't know which mass is the bottom one. But I think that you can just get \(a\) from the problem. It's given! The mass will be, on average, experiencing that same acceleration, despite it's velocity :)

So, I think \(F_\text{net}=m\ a\) is appropriate.

Answer 2

Hmmm, wait...

Answer 3

I guess I should specify,

\(F_\text{net}=F_g+F_s\), right?

That should let you find the spring force, right?