Chapter 21, Problem 57P

The telephone-cable reel rolls without slipping on the horizontal surface. If point A on the cable has a velocity VÀ = 0.84 m/s to the right, compute the velocity of the center O (positive if to the right, negative if to the left) and the angular velocity w (positive if counterclockwise, negative if clockwise) of the reel. Answers: Vo = W = 1.91 m 4 0.69 m 1.315 i 1.376 Ho m/s VA rad/s

The 110-kg wheel has a radius of gyration about its center O of ko = 220 mm, and radius r = 0.4 m. When the wheel is subjected to the constant couple moment M = 63 N•m, it starts rolling from rest. Determine the wheel's angular velocity W (in rad/s) after 6.0 seconds if the wheel has been rolling without slipping. Please pay attention: the numbers may change since they are randomized. Your answer must include 2 places after the decimal point. Take g = 9.81 m/s². T M Your Answer: Answer

The circular disk of 270-mm radius has a mass of 36 kg with centroidal radius of gyration k = 235 mm and has a concentric circular groove of 105-mm radius cut into it. A steady force T is applied at an angle to a cord wrapped around the groove as shown. If T = 59N, 0 = 29°, μs = 0.08, and μk = 0.07, determine the angular acceleration a of the disk, the acceleration a of its mass center G, and the friction force F which the surface exerts on the disk. The angular acceleration a is positive if counterclockwise, negative if clockwise; the acceleration a is positive if to the right, negative if to the left; and the friction force F is positive if to the right, negative if to the left. m= 36 kg k 235 mm 270 mm T G Ug = 0.08 Uh = 0.07 105 mm.