Thanks. This one too.
http://img94.imageshack.us/img94/7417/blahfu.png
Answer : 1.4m/s^2
LOL at the image name "Blahfu"

There are two forces acting here, the force of gravity acting on the block, and the force of friction, which is 6N.
The force pulling the weight down is,

Therefore, the net force is,

Now, when doing these calculations, there is uniform acceleration, because the acceleration of the 8 KG box is the same as the acceleration of the 2 KG box.
So,

a)

