Hey can someone walk me through this problem? Thanks!! A person is doing leg lif
ID: 2260312 • Letter: H
Question
Hey can someone walk me through this problem? Thanks!!
A person is doing leg lifts with 3.0-kg ankle weights. She is sitting in a chair with her
legs bent at a right angle initially. The quadriceps muscles are attached to the patella via
a tendon; the patella is connected to the tibia by the patellar tendon, which attaches to
bone 10.0 cm below the knee joint. Assume that the tendon pulls at an angle of 20.0°
with respect to the lower leg, regardless of the position of the lower leg. The lower leg
has a mass of 5.0 kg and its center of gravity is 22 cm below the knee. The ankle weight
is 41 cm from the knee. If the person lifts one leg, find the force exerted by the patellar
tendon to hold the leg at an angle of (a) 30.0° and (b) 90.0° with respect to the vertical.
Explanation / Answer
right answer is : (b) 90.0