Calculating Coefficient of Friction for Two Blocks

[cosmoo]

Homework Statement

We have two block of mass that rest upon each other. A force is applied to the top block and that cause both of the blocks to accelerate at different rates. What are the coefficient of friction needed to achieve this, assuming that bottom block rest on a frictionless surface.

Homework Equations

- Basic force equations.

The Attempt at a Solution

We are not sure where to start because we are not unsure how mass of two blocks will effect the question. Also unsure of how the force will apply to the bottom block. Would this be the Force multiplied by the coefficient of friction?

 

[Delphi51]

The force of friction between the blocks is the "grip" each has on the other.
Just set up a list of forces for each block, including that force of friction for both.