Question

A person is sitting with one leg outstretched, so that it makes an angle of = 39.9o with the horizontal. The weight of the leg below the knee is 34.7 N with the center of gravity located below the knee joint. The leg is being held in this position because of the force M applied by the quadriceps muscle, which is attached 0.100 m below the knee joint (see the drawing). Obtain the magnitude of M