4.  Two children hang by their hands from the same tree branch. The branch is straight, and grows out from the tree trunk at an angle of 27.0° above the horizontal. One child, with a mass of 44.0 kg, is hanging 1.30 m along the branch from the tree trunk. The other child, with a mass of 35.0 kg, is hanging 2.10 m from the tree trunk. What is the magnitude of the net torque exerted on the branch by the children? Assume that the axis is located where the branch joins the tree trunk and is perpendicular to the plane formed by the branch and the trunk.

The Drawing shows the relationships and distances are.  The net torque is the sum of the torques created by each child.

 

 

I am going to use the perpendicular distances which are shown above.  Given the way gravity pulls down that makes both of the children’s torque be Counter-Clockwise.  So

 

 

 

 

 

 

 

 

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This page last updated on January 11, 2020