The patella P located in the human knee joint is subjected to tendon forces T₁ and T₂ and a force F exerted on the patella by the femoral articular A. If the directions of these forces are estimated from an X-ray as shown, determine the magnitudes of T₁ and F when the tendon force T₂ = 6 lb.. The forces are concurrent at point O.

Determine the magnitude and direction of the resultant force F_AB exerted along link AB by the tractive apparatus shown. The suspended mass is 10 kg. Neglect the size of the pulley at A.

A "scale" is constructed with a 4-ft-long cord and the 10-lb block D. The cord is fixed to a pin at A and passes over two small pulleys at B and C. Determine the weight of the suspended block E if the system is in equilibrium when s = 1.5 ft.