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Mechanics application problem

  • Thread starter luysion
  • Start date
  • #1
35
0

Homework Statement


When an athlete
throws a javelin her forearm snaps through an angle of
approximately ¼ radians in 0.20 s. The athlete’s hand moves
with approximately constant speed, the length of her forearm
is 45 cm, and the combined mass of her forearm and javelin
is 2.0 kg. Assuming that the system is well approximated by
a mass of 2.0 kg located 45 cm from the pivot, what force do
the ligaments holding the forearm to the elbow need to exert?

Homework Equations





The Attempt at a Solution



Im getting lost, I cant interpret the question easily. I really have no idea how to do this.
I can picture some sort of lever mechanism but other than that, im confused as to what to do with the angular displacement value and the time period value theyve given us.

cheers
 

Answers and Replies

  • #2
674
2
Looks more like a centripetal force problem to me, unless I am reading it wrong. I am no biology expert, but I believe the ligaments are attaching the forearm with the elbow so it will experience a force due to the circular motion of the javelin. You will need to calculate this force based on what you know about centripetal acceleration.
 

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