Finding Magnitude Homework: Inequality for Moving Blocks Together

[Physicsnoob90]

Homework Statement

Two blocks are stacked one on top of the other with mass m1 on top and m1/m2= 3.0. There is no friction between m2 and the ground, but the coefficient of friction between m1 and m2 are given by μk= 0.40 and μs= 0.50. For what magnitudes of force acting horizontally on m1 do the two blocks move together. (i.e. , no slide on one another), express answer as an inequality.

Homework Equations

The Attempt at a Solution

i already written down all forces acting on both blocks but i am having issues finding the masses since m1/m2 = 3.0

 

[AlephNumbers]

A classic. You have to show your work before anyone can help you. Also list the relevant equations.

 

[haruspex]

i am having issues finding the masses since m1/m2 = 3.0

So write the masses as 3m and m, for some unknown m. Trust the question - the m's will cancel later.