Rotational dynamics/Rigid objects in equilibrium

[giant016]

Homework Statement

Homework Equations

Net force of the Y vector: -F1 + F2 - weight = 0

The Attempt at a Solution

I tried to solve the equation thinking that m could = torque (torque=force X length of lever arm) but I couldn't figure out how to fit in that .025m spot in between the joint and the muscle. Not sure if the equation provided will really help. Any help is appreciated!

 

[ShawnD]

The question is tricky because the M force is drawn in the wrong direction. The M force is the blue arrow up, not a black arrow going right. Put an equation equal to 0 where clockwise moments are positive and counterclockwise are negative
0 = (0.025)(M) + (0.15)(22) - (0.3)(111)
M = 1200N

That doesn't seem right. That's equivalent to 122kg, resting on 1 muscle.

 

[giant016]

The question is tricky because the M force is drawn in the wrong direction. The M force is the blue arrow up, not a black arrow going right. Put an equation equal to 0 where clockwise moments are positive and counterclockwise are negative
0 = (0.025)(M) + (0.15)(22) - (0.3)(111)
M = 1200N

That doesn't seem right. That's equivalent to 122kg, resting on 1 muscle.

We have an answer sheet (it's a multiple choice question) and one of the answers is 1.2X10^3, and your equation makes sense, so...Thanks! I'm on some other forums (mostly car junk) and I've never gotten an answer that quick!