Question

The Russell Traction System To immobilize a fractured femur (the thigh bone), doctors often utilize the Russell traction system illustrated in the figure. Notice that one force is applied directly to the knee, F_1,while two other forces, F_2 and F_3 are applied to the foot. The latter two forces combine to give a force F_2 + F_3 that is transmitted through the lower leg to the knee. The result is that the knee experiences the total force F_{total} = F_1 + F_2 + F_3. The goal of this traction system is to have F_{total} directly in line with the fractured femur, at an angle of 20.0 above the horizontal.

1. Find the angle \theta required to produce this alignment of F_{total}. (Assume the pulleys are ideal.)

2. Find the magnitude of the force, F_{total} that is applied to the femur in this case.

I tried tutoring with both these questions and even they could not help me. I really hope and pray Jiska can.

Answer 1

Jenny are there any numbers for forces?

Answer 2

I not sure if this can be answered =-(

Answer 3

This is an image I found, but it does not fit the description.
http://3.bp.blogspot.com/_-WsaCfPPjYQ/SIqbam3U7QI/AAAAAAAAAtI/JV4ysqn2BPQ/s320/pelvic_belt_traction.jpg
Can you describe the figure that we don't see?

Answer 4

For the angle you have to add all angles, so u get 60 degrees. I am not sure about the Ftotal.
Hope this helps!