# Determining an expression for acceleration

1. Oct 3, 2012

### kobylorat

1. The problem statement, all variables and given/known data

Here is the question: http://i1110.photobucket.com/albums/h459/granolup/Untitled.png [Broken]

It is assumed that the blocks are not moving.

2. Relevant equations

F=ma
N=mg
friction = umg

3. The attempt at a solution

I have started out drawing free-body diagrams for each of the three wedges.
For m1, there is a force due to gravity pointing downwards, a normal force pointing to the top right.
For m2, there is a force due to gravity pointing downwards, a normal force pointing to the bottom left, and the force of kinetic friction pointing to the top left.
For m3, there is a force due to gravity pointing downards, and a normal force pointing upwards.

Last edited by a moderator: May 6, 2017
2. Oct 3, 2012

### tiny-tim

welcome to pf!

hi kobylorat! welcome to pf!
ok so far (but isn't there also a friction force from the ground, and between 2 and 3?) …

now write out the equations of motion, including a purely geometric equation which specifies that block 2 stays on block 1