7. Friction, Inclines, Systems

When stacking identical uniform blocks of length $L$ on top of each other at the edge of a table, what is the maximum total overhang achievable before the stack becomes unstable?

Which of the following statements about stacking blocks to form stable structures is correct?

A 4kg block sits on top of a 6kg block which is on a frictionless surface. The coefficients of friction between the two blocks are μ_s=0.5 and μ_k=0.3. Calculate the maximum force you can pull on the bottom block with so that the objects move together.