A 4-lb ball revolves in a horizontal circle as shown. Knowing that L = 3ft and t
ID: 1817942 • Letter: A
Question
A 4-lb ball revolves in a horizontal circle as shown. Knowing that L = 3ft and the maximum allowable tension in the cord is 10lb,(a) determine the maximum speed, and (b) the corresponding value of the angle.
Explanation / Answer
from the free body diagram we get Tcostheta = 4 ------------>(1) Tsintheta = m(v^2)/r --------->(2) r = Lsintheta so we get v^2 = (T/m)((sintheta)^2 ) * L ------->(3) costheta = 4/T if T is maximum cos is minimum and sin is maximum so T*sin is max so v is max so for max v T = 10lb and costheta = 4/10 so theta = 66.42 degrees and substituting in (3) we get v = 14.243 ft/s check calculations