Force required to move two boxes stacked on top of one another.

[fd25t6]

Homework Statement

Hello, i was just hoping someone could check my work on a problem I am working on.

There are two boxes stacked on top of one another m2 is the bottom box which is sitting on the ground and has a weight of 10N. m1 is on top of it and has a weight of 5N. Directly to the left there is a pulley on a wall guiding a rope which extends straight out to the two boxes connecting them together. The bottom box(m2) is going to move right thus causing the top one to move left. The question asks for the mount of force (pull on box m2) required to cause both boxes to move at a constant speed. friction coefficient of .40 between all surfaces in contact.

Homework Equations

Ff= fn*uk

The Attempt at a Solution

Ok so i did a free body diagram for each one of the boxes individually, and in both cases the sum of all forces are going to be equal to zero because of the constant acceleration.these are all assuming up and right to be positive.
For m1(top box)
the sum of all forces= -Ft+Ff = -Ft+ .4(5) = Ft= 2N

For m2 (bottom box)
the sum of all forces are= Fpull-Ff-Ft= Fpull-10(.4)-2= fpull -4 -2=0... fpull= 6N

a force of 6Newtons is required to get both boxes moving at a constant v?
thanks for the help

 

[gb7nash]

We need more information. What kind of boxes are they?

 

[fd25t6]

sorry my computer was acting weird i edited in the rest of the info.