Question

For any given single trial of the arms out position, would the linear velocity at the shoulder be greater than, less than, or the same as the linear velocity at the wrist? Is the linear displacement at the shoulder greater than, less than, or the same as the linear displacement at the wrist? Explain your answers.

Answer 1

when the arm rotates about the shoulder
the wrist is at a grater distance from the shoulder thant the points closer to the shoulder
now, since the whole arm moves as one body, its angular speed is the same ( for all points on the arm)
hence
linear speed will be greater at points farther away from the pivot of rotation
that is why the linear velocity of the points on wrist is more than the linear velicty of poionts closer to the shoulder

Again, linear displacement of the points on the wrist woiuld be greater too due to the greater speed of the point on th ewrist