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## Homework Statement

The two blocks (m = 12 kg and M = 98 kg) in Fig. 6-38 are not attached to each other. The coefficient of static friction between the blocks is μs = 0.37, but the surface beneath the larger block is frictionless. What is the minimum magnitude F of the horizontal force required to keep the smaller block from slipping down the larger block?

## Homework Equations

F=ma

F

_{s}=U

_{s}(Fn)

## The Attempt at a Solution

Not sure how to do this one. So far I got that Sum of F = 0 because the block is ont accelerating.

The big block is moving because it is frictionless at the bottom and it is being pushed by the horizontal force F.

F

_{s}has to > gravity so that gravity doesn't move the small block

So F

_{s}> mg

F

_{n}*U

_{s}> mg

that's all the thoughts I have so far... but it can't be that simple because the big block is moving, so more force has to be applied. But the more force that is applied, the more the big block moves... and my thoughts just end up in circles.

Also, I'm not sure if the horizontal force F includes the normal force already, or do I have to add the normal force when doing sum of forces = 0 ?