Question

Now, three masses (m1 = 3.1 kg, m2 = 9.3 kg and m3 = 6.2) hang from three identical springs in a motionless elevator. The springs all have the same spring constant given above.
Now the elevator is moving downward with a velocity of v = -2.9 m/s but accelerating upward at an acceleration of a = 3.6 m/s2. (Note: an upward acceleration when the elevator is moving down means the elevator is slowing down.)
What is the magnitude of the net force on the middle mass?
I got 33.48 by using F=ma and that was wrong, so was the negative answer.

Answer 1

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Answer 2

https://www.jiskha.com/questions/1775371/Now-three-masses-m1-3-1-kg-m2-9-3-kg-and-m3-6-2-hang-from-three-identical#1777035