Another Equilibrium Example
: If the mass of the girls is 75 kg, what is the maximum tension in the guy’s arms?
: Assume girls make 45o angle with horizontal, and c.g. 2/3 of way from feet to shoulders. Choose axis at feet and use St= 0.
Notes:
We looked at this cartoon before, assuming it was static friction that limited the girls’ ability to apply tension to the guy’s arm. Now we assume that the girls can “dig in their heels”, and find that the requirements of static equilibrium also constrain their ability to pull.
Basically, we find, by setting sum of torques to zero,
-3Tsin(45) + 2 Wsin(45) =0