A woman lifts a 7.2-kg barbell in each hand with her arm in a horizontal position...

A woman lifts a 7.2-kg barbell in each hand with her arm in a horizontal position at the side of her body and holds it there for 3 s. The deltoid attaches 13 cm from the shoulder joint and makes a 13∘ angle with the humerus. The barbell in her hand is 0.55 m from the shoulder joint, and the center of mass of her 4.0-kg arm is 0.24 m from the joint.

1. Determine the magnitude of the force that the lifter's shoulder joint exerts on her humerus. Express your answer with the appropriate units.

2. Determine the direction of the force (measured clockwise from the positive x-axis) that the lifter's shoulder joint exerts on her humerus. Express your answer with the appropriate units.

I already found the force the deltoid exerts on the humerus (with help) but I am not sure how to even set up these problems. Any help is great, thank you!

Solutions

Expert Solution

b) Angle is,

= Tan^-1[-261/1607]

= -9.225^o with +x axis,

9.225^o Clockwise from +x axis .

I hope you understood the problem and got your answers, If yes rate me!! or else comment for a better solutions.

genius_generous answered 1 week ago

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