Exerting a force

Question

When an athlete throws a javelin her forearm snaps through an angle of approximately pi radians in 0.20 s. The athletes 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?

Answer 1

Firs calculate ω = θ/t = π/0.2

Then find a =rωω r=0.45m

Then F = m a m= 2.0kg