Question

3 masses connected by identical springs hang in an elevator accelerating downward, what is the net force on the MIDDLE mass?

Answer 1

can you draw the situation first?

Answer 2

http://www.smartphysics.com/Content/Media/Images/Mechanics/05/masseshangingfromsprings2smaller.png

Answer 3

Consider m3 first, mg-k*dx3=ma
a is not known?

Answer 4

acceleration is 1.5 m/s^2 downward

Answer 5

then you can find k*dx3,

Answer 6

whats k*dx3? :s

Answer 7

k is spring constant time, what is dx3?

Answer 8

dx3 is extension of spring 3,

Answer 9

how do you find that? is it m3g?

Answer 10

Find k*dx3 as a whole first.
mg-k*dx3=ma

Answer 11

i dont understand how im calculating dx3 though

Answer 12

three masses (m1 = 2.7 kg, m2 = 8.1 kg and m3 = 5.4) hang from three identical springs in a motionless elevator. The springs all have the same spring constant k=299. the elevator is moving downward with a velocity of v = -3.2 m/s but accelerating downward at an acceleration of a = -1.5 m/s^2. What is the magnitude of the net force on the middle mass?

Answer 13

thats the full question to give you a better understanding.