EK physics question!! Help!

[jade1013]

I'm not so great at torque and I was working through question 60 in lecture 3 of the exam krackers book for physics. The answer says that the clockwise torque is the weight of the board times 0.3m. Where is the 0.3m coming from? Please help me!! Thank you!

---

Members don't see this ad.

 

[Muscles00GT]

Might be more helpful if you post the question...Not everyone has the same EK book

 

[mvenus929]

They chose the point where the Tension is as their point of rotation. We know that the center of mass of the board is in the middle of it, since it is a uniform density board. The question also says that the board is a meter long. Thus, the center of gravity of the board is 0.5m from the end of the board, or 0.3m from the point of rotation.