When you lift an object by moving only your forearm, the main lifting muscle in your arm is the biceps. Suppose the mass of a forearm with hand is 1.80 kg. If the biceps is connected to the forearm a distance of 2.50 cm from the elbow, what is the magnitude of the torque exerted by the biceps to hold a 44.5 N (about 10 lbs) ball at the end of the forearm at distance of 35.0 cm from the elbow, with the forearm parallel to the floor, 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. driceps -Biceps -drall

A simple pendulum consists of a small object of mass 3.5 kg hanging at the end of a 2.0-m-long light string that is connected to a pivot point. (a) Calculate the magnitude of the torque (due to the force of gravity) about this pivot point when the string makes a 7.0° angle with the vertical. (b) Does the torque increase or decrease as the angle increase?

(a) When opening a door, you push on it perpendicularly with a force of 44.0 N at a distance of 0.780 m from the hinges. What torque (in N-m) are you exerting relative to the hinges? (Enter the magnitude.) N-m (b) Does it matter if you push at the same height as the hinges? O Yes O No

Force F = (-7.0 N)î + (5.0 N) ĵ acts on a particle with position vector7 = (4.0 m)î + (5.0 m) ĵ. (a) What is the torque on the particle about the origin, in unit-vector notation? = N: m (b) What is the angle between the directions of r and Torque is the cross product of a position vector (extending from a chosen point, here the origin, to the particle) and a force vector. Did you take the cross product in unit-vector notation? Do you remember how find the angle between two vectors by taking a dot product in both unit-vector notation and also in magnitude-angle notation? (You can similarly use a cross product to do this.) Do you remember how to find the magnitude of a vector from its components?

An electric motor rotating a workshop grinding wheel at 1.08 x 10 rev/min is switched off. Assume the wheel has a constant negative angular acceleration of magnitude 2.06 rad/s? (a) How long does it take the grinding wheel to stop? Note that the time required for the wheel to stop is the same as the time for the wheel to start from rest and reach the given angular speed with the same magnitude angular acceleration, s (b) Through how many radians has the wheel turned during the time interval found in part (a)? It might be helpful to translate this problems into linear variables (a car traveling with an initial speed and then slowing down with a constant negative acceleration), rad Need Help? Road Master

Real-world application. Equipment: a barbell (above 10 lbs) or a heavy book, a meter stick or Upper another length measuring instrument. Lift the Biceps barbell by doing a bicep curl. Watch the change of arm Barbell the shape of your bicep. What is the role of the bicep in lifting the barbell? Where is it attached to the arm? Consider the axis of rotation to be in the 4.0 cm elbow joint. How far away is the barbell from the axis of rotation? How far is the bicep from the 40 cm axis of rotation? Estimate the force that the biceps muscle exerts on the forearm holding the barbell. What assumptions did you make in working the problem?

A man in a gym is holding an 8.0-kg kettlebell at arm's length, a distance of 0.55 m from his shoulder joint. What is the torque about his shoulder joint due to the gravitational force on the kettlebell if his arm is held at 30° below the horizontal?