Apoint on the rim of a 0.75 m diameter grinding wheel changes speed uniformly from 11 m/s to 20 m/s in 8.1 s. what is the average angular acceleration of the wheel during this interval?

3.0 sâ»Â˛ We can calculate the tangential acceleration by dividing the change in speed by the elapsed time, e.g. (vâ‚ - vâ‚€) / t = (20 m/s - 11 m/s) / 8.1 s = 1.111 m/s² Now we can calculate the angular acceleration by dividing by the radius. The radius of the wheel is half its diameter, so r = 0.75 m / 2 = 0.375 m Finally, the angular acceleration is 1.111 m/s² / 0.375m = 3.0 sâ»Â˛ The unit sâ»Â˛ is just an alternate way of writing 1/s².

The body may be changing its direction due to which velocity get zero because velocity is the distance covered by an object in some time and in a particular direction.