You are given the rate of rotation of a wheel as well as its radius. In each case, determine the following: (a) the angular speed, in units of radians/sec; (b) the linear speed, in units of cm/sec, of a point on the circumference of the wheel; and (c) the linear speed, in cm/sec, of a point halfway between the center of the wheel and the circumference.
15 revolutions/sec: $r=20 \mathrm{cm}$