(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

How much torque must the pin exert to keep the rod from rotating ?

2. Relevant equations

3. The attempt at a solution

Tnet=0= -(.500kg)(9.80)(.80m) - (2.0kg)(9.80)(.40m) + torque of pin

Torque of pin = 11.76 Nm which is correct, but I am confused about something

To get this answer I found the torque about the pin and said that the torque exerted by the pin must equal that. But I thought that for static equilibrium, the torque around each point had to be zero, and it is not 0 around the pin in this case. Why is this?

For other problems, my book suggests to pick a point as the pivot point. Then the torque of the forces at that point becomes zero and the sum of the torques of the other forces around this pivot must equal zero. This is what bothers me about this question. If I pick the pin as the pivot, shouldn't sum of torques exerted by gravity on the rod & mass = 0?

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# Homework Help: Quick Torque Question

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