Question

Chapter 09, Problem 83 Chalkboard Video Two spheres are each rotating at an angular speed of 21.9 rad/s about axes that pass through their centers. Each has a radius of 0.430 m and a mass of 1.66 kg. However, as the figure shows, one is solid and the other is a thin-walled spherical shell. Suddenly, a net external torque due to friction (magnitude-0.1 20 N·m) begins to act on each sphere and slows the motion down. How long does it take (a) the solid sphere and (bhethin-walled sphere to come to a halti? sphere nd os the ion don. How Thin-walled spherical shell Solid sphere (a) Number Units (b) Number Units

Answer 1

a] Time taken = angular momentum/Torque = iw/T = (2/5 mr^2*w)/T = (2/5 *1.66*0.43^2*21.9)/0.12 = 22.41 s

b] Time taken = angular momentum/Torque = iw/T = (2/3 mr^2*w)/T = (2/3 *1.66*0.43^2*21.9)/0.12 = 37.34 s