measuring knee stress with hooke's law

[vancan007]

I built a model of the knee to measure the stress put on the patella. To do so, I must use hooke's law. I under stand that in f=-kx, x is the distance, but how do I find the k variable? The k variable being the spring constant of the spring...how do I find it? Please please please help! My project is due on Jan 24th!

[deleted-2131]

Hi vancan007,

To calculate the spring constant, k, you will need to measure the force you apply to the spring to stretch the spring by a certain distance. Then, plug the force and distance into Hooke's law and solve for k. For example, let's say that I applied 10 Newtons of force to the spring, and the spring extended by 20 cm. Since

f = -kx
-f/x = k
-10 newtons/0.2m = k
k = -50 Newtons/meter

[vancan007]

Thank you so much!