# Force problem with three masses and two pulleys

## Homework Statement

For the apparatus in the figure, what is the minimum value of the coefficient of static friction between the block (m3) and the table that would keep the system at rest if m1 = 0.10 kg, m2 = 0.20 kg, and m3 = 0.30 kg? (Assume ideal conditions for the string and pulleys.)

F=ma
a= Fnet/mtotal

## The Attempt at a Solution

This assignment is extra credit since we havent been taught how to solve these problems yet. I watched multiple three mass, two pulley videos.They are all solving for acceleration with the mu value. I tried using what I saw to adjust to my situation.

I attempted using the formula a=Fnet/Mtotal
a=((4kg)(9.8m/s^2)-(1kg)(9.8m/s^2)(mu)-(2kg)(9.8m/s^2))/7kg

I plugged in my known values
a=(39.2−(9.8)(μ)−19.6)/7

I then moved my 7 over to the a
7a=39.2−(9.8)(μ)−19.6

I am assuming that I should be able calculate acceleration with my known values since I'm solving for mu but haven't figured out the steps to do so

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kuruman
Homework Helper
Gold Member
Hi Dayanara Avilez and welcome to PF.

Can you please post the figure? Without it it's hard to check your work.

phinds
Gold Member
2019 Award
Probably be easier to help you if you actually posted the figure you are referencing

Sorry for the delay! I was figuring out how to attach photos once I saw the replies
Probably be easier to help you if you actually posted the figure you are referencing

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