A wheel 80.0 cm in diameter accelerates uniformly from 215 rpm to 360 rpm. If in this process a point on the edge of this wheel have traveled 118 m, how long does this process take?

Answer 1

C = pi*D = 3.14 * 80 = 251.3cm = 2.51m
C=2.51m/rev=2.51m/6.28rad=2.51m/360Deg.

Rev = 118m * (1/ 2.51)rev/m = 47.

360 - 215 = 145rev/min.
t = 47rev * (1/145)min/rev = 0.324min.
= 19.4s.