Problem 33P

Suppose the hand in Problem 32 holds a 15-kg mass. What force, FM, is required of the deltoid muscle, assuming the mass is 52 cm from the shoulder joint?

Problem 32

(a) Calculate the force, FM, required of the “deltoid” muscle to hold up the outstretched arm shown in Fig. 9–65. The total mass of the arm is 3.3 kg. (b) Calculate the magnitude of the force FJ exerted by the shoulder joint on the upper arm.

FIGURE 9–65

Step 1 of 4The angular momentum of an object about an axis of rotation is measured by theproduct of the linear momentum of the object and the perpendicular distancebetween the object and the axis of rotationSuppose an object of mass m is revolving around a circle of radius r with speed vabout an axis passing through center ,The linear momentum of the object, p =mv.The angular momentum of an object, L = linear momentum x perpendicular distancefrom the axis of rotation. or, L = p rTherefore, L = m v rSince v = r, where w is the angular velocity of the object, the angular momentum canbe written as L = m ( r) r 2or, L = m r L= I