Struggling with Torque Problems in Static Equilibrium?

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stonecoldgen
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1. Homework Statement

I need help with #2 and #5.

#2 just aks what is the mass of m1, in order for the system to be in static equilibrium

#5 aks what angle will the disk spin when pushed to go up that step. It also asks what is the minimum force needed in order for the disk to go up.
3. The Attempt at a Solution
I tried solving #2 just like i did with #1. They are giving me 2 sets of distances (in #1 just one) i also tried with the other set of distances and it didnt work. I even tried combinating the 2 sets of distances and not even that works.

For #5 tried combinating some formulas:

∑F
_______________ = a/r = ΔΘ/Δt
∑m

but all of those unkowns ''freak me out''
EDIT: and you can see that my teacher has an answer bank, i know that Θ is obviously 30, but i don't know how to get there
 
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  • Handwritten worksheet titled Newton's Laws: Torque with several static-equilibrium problems, including a beam with masses, a board on a support, a person on a platform, a ladder-like incline with friction, and a disk on a step with forces labeled.
    angular acceleration0001.jpg
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For #2, can you identify all the masses that are exerting torques about the pivot point? What are they, and where are their centers of mass located?
 
gneill said:
For #2, can you identify all the masses that are exerting torques about the pivot point? What are they, and where are their centers of mass located?

i keep getting 130kg, which is not on the answer bank, I am i doing it wrong or did the teacher made a mistake with the answer bank?
 
stonecoldgen said:
i keep getting 130kg, which is not on the answer bank, I am i doing it wrong or did the teacher made a mistake with the answer bank?

You'll have to show your work before we can comment on why or where you might be making a mistake. What choices does the answer bank give?
 
gneill said:
You'll have to show your work before we can comment on why or where you might be making a mistake. What choices does the answer bank give?

no don't worry about it, i finally got the right answer, i just saw things from another perspective (because i don't know about you, but i tend to commit the same error more than once) and got it