Physics education research, electronic materials, and the musings of Christopher Moore, Ph.D.

1. The problem statement, all variables and given/known data

1. Consider a man throwing a baseball. Given the following, calculate the velocity of the ball as it leaves his hand:
1. The distance from his shoulder socket (humeral head) to the ball is 70 cm.
2. The distance from his humeral head to the points of insertion of the muscles moving his arm forward is 9 cm (this is a simplification, as the shoulder is a complex joint).
3. The velocity of the muscle shortening is 2.6 m/sec..

Show your calculations neatly in the space provided to receive credit for your answer.
Express your answer in m /sec., and round your answer to the nearest tenth.


2. Relevant equations

Velocity = Distance / Time ????

3. The attempt at a solution

Here is my first attempt at this problem: 2.6 m/ sec = 260 cm/ sec.

70 - 9 = 61 cm

61 cm / 260 cm per second = 0.23 m /second?

Can anybody help me on how I should start this question? I would like to know how to start so I can begin to wrap my brain at it. Thank you. P.S. I don't know really know anything about velocity other than what I wrote above. Thank you!


After much thought, there seems to be 3 points that make up what appears to be triangle:


First point: 70 cm
Second Point: 9 cm
Last Point: 61 cm



How do I calculate the velocity for one of these angles? Perhaps, if calculate all then I should add up the velocity for my answer.