One yoga exercise, known as the \"Downward-Facing Dog,\" requires stretching you
ID: 1976045 • Letter: O
Question
One yoga exercise, known as the "Downward-Facing Dog," requires stretching your hands straight out above your head and bending down to lean against the floor. This exercise is performed by a certain 735 N person, as shown in the simplified model in the figure below . When he bends his body at the hip to a 90.0 degree angle between his legs and trunk, his legs, trunk, head and arms have the dimensions indicated. Furthermore, his legs and feet weigh a total of 250 N, and their center of mass is 41.0 cm from his hip, measured along his legs. The person's trunk, head, and arms weigh 485 N, and their center of gravity is 65.0 cm from his hip, measured along the upper body.Find the normal force that the floor exerts on each foot, assuming that the person does not favor either hand or either foot.
Explanation / Answer
Hint: First treat his entire body as a system, then isolate either the legs or upper body. 2. Relevant equations Static equilibrium equations (net force = 0, net torque = 0) draw a right triangle, and found the other two angles using the inverse of tan. I then isolated the legs, making the pivot point at the hips. Afterwards, draw a free body diagram of the legs, noting that the legs made an angle of 56.3099 degrees with the horizontal, and using this information I set up a net torque expression as such: net torque = rNFN + rFFF = 0, where the subscript N denotes normal force and F denotes the weight of the feet and legs. then plug in the following values: 0 = (0.9sin33.69)FN + (0.41sin33.69)(-277N) and solved for the normal force, which came out to be: 126.18889N. Dividing this by 2 got me: 63.1N per foot, which is wrong; this answer is supposed to be 200N per foot. Am I missing a force in my method here, or is there another mistake I am making? If anyone can help me out it would be greatly appreciated, thanks in advance.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.