Problem 7: The triceps muscle in the back of the upper arm is primarily used to extend the forearm. Suppose this muscle in a professional boxer exerts a force of 2.05 × 10³ N with an effective perpendicular lever arm of 3.25 cm, producing an angular acceleration of the forearm of 105 rad/s². What is the moment of inertia of the forearm, in kilogram meters squared?

If you hold your arm outstretched with your palm upward, the force to keep your arm from falling comes from your deltoid muscle. Assume that the arm with hand has mass 4.25 kg and the distances and angles shown. What is the magnitude of the torque must the deltoid muscle provide to keep the arm in this position, in N·m? Use g = 10.0 m/s2. Your answer needs to have 3 significant figures, including the negative sign in your answer if needed. Do not include the positive sign if the answer is positive. No unit is needed in your answer, it is already given in the question statement.

A ballerina spins initially at 1.56 rev/s when her arms are extended. She then draws in her arms to her body and her moment of inertia becomes 0.82 kg-m², and her angular speed increases to 4.43 rev/s. What was her initial moment of inertia? Give your answer in kg-m².

An old grindstone, used for sharpening tools, is a solid cylindrical wheel that can rotate about its central axle with negligible friction. The radius of the wheel is 0.330 m. A constant tangential force of 200 N applied to its edge causes the wheel to have an angular acceleration of 0.936 rad/s². (a) What is the moment of inertia of the wheel (in kg. m²)? kg - m² (b) What is the mass (in kg) of the wheel? kg (c) The wheel starts from rest and the tangential force remains constant over a time period of 5.50 s. What is the angular speed (in rad/s) of the wheel at the end of this time period? rad/s F9 D