To treat fractures of the humerus shaft, a cast and traction device is used; such that the cast of the upper arm is bent by 100 degrees to 110 degrees at the elbow joint. The traction device is an object of mass M that is hung at the elbow, it keeps the upper arm under tension. What is the range of masses for the traction device used if the muscle force it must compensate ranges from 5N to 10N?

Question

My ans:

Using fbd: Fnet: T- Mg = 0
5- Mg =0
-M =-5/g

Of course I realized this is wrong since I never used the angles given, but I have no idea...