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## Homework Statement

A block with mass m1 = 9.4 kg is on an incline with an angle θ = 31.0° with respect to the horizontal.

Now a new block is attached to the first block. The new block is made of a different material and has a coefficient of static friction μ = 0.9. What minimum mass is needed to keep the system from accelerating?

## Homework Equations

Ft,1 = Ft,2

Fg,1 = m1*g

Fg,2 = m2*g

Fn,1= Fg,1*cos 31

Fn,2 = Fg,2*cos 31

Ff,s,2 = Fn*.9

## The Attempt at a Solution

Ft,1 = Ft,2

Fg,1 = m1*g = 92.12N

Fg,2 = m2*g = m2*9.8

Fn,1= Fg,1*cos 31

Fn,2 = Fg,2*cos 31

Ff,s,2 = Fn*.9

I'm not really sure what to do after this. I have some free-body diagrams set up, but since I can't post them here, I can't show them.

I had a value for the coefficient of static friction, but that was for a system with a spring (.292), so I don't think that'll work here. I also have one for kinetic friction (.212), but that might not apply here. After that, I'm stuck.