Apitcher is in 85° of abduction, holding a 1.4 n baseball at point c, 65 cm from the joint axis at point o • the center of gravity of his arm is 25 cm from the joint axis of shoulder abduction at point o • the weight of the arm w is 0.06 of the pitcher’s weight of 100 n • deltoids muscles are at an angle θ of 15° with respect to the humerus and insert 15 cm from the joint axis at point a • determine the force applied by the deltoid muscles and the joint reaction force at the shoulder joint and its orientation β

I attached a Diagram for this problem.

We star considering the system is in equlibrium, so

Fm makes with vertical

Fm makes 70 with vertical

Applying summatory in X we have,

We know that W is equal to

Substituting,

For the second part we know that the reaction force Fj on deltoid Muscle is equal to Fm, We can assume also that

lol

explanation:

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.