How Does Friction Affect the Acceleration in a Pulley System?

[algar32]

Homework Statement

A system comprised blocks, a light frictionless pulley, and connecting ropes is shown in the figure. The 9.0-kg block is on a perfectly smooth horizontal table. The surfaces of the 12-kg block are rough, with \mu_k = 0.30 between the block and the table. If the 5.0-kg block accelerates downward when it is released, find its acceleration.

the figure looks like this picture (except M= 5kg):
http://www.cramster.com/answers-feb-11/physics/system-comprising-blocks-system-comprising-blocks-light-frictionless-pulle_1126069.aspx?rec=0

14 minutes ago
- 4 days left to answer.

Homework Equations

The Attempt at a Solution

I want to say it is 1.6 m/s^s but I am not sure If I did it right.
I just added the force friction to the force tension and then divided by the weights (9+5).
Not sure if this is correct or not.

 

[tal444]

Looks right to me.

 

[emailanmol]

This is very similar to the earlier problem you asked.

Use those equations to find the answer :-)

 

[tal444]

Looks right to me.

EDIT: I was doing this question wrong earlier, refer to emailanmol's posts in your other thread.