Angular speed from 200rpm to 450 rpm express this range of angular speed in radians per second?

Question

Angular speed from 200rpm to 450 rpm express this range of angular speed in radians per second?

Answer 1

( 200 rev / minute ) ( 2 pi radians / 1 rev ) ( 1 minute / 60 sec ) = 21 radians / sec.

Similarly, 450 rpm is 52 radians / sec.

Answer 2

Take 200, divide by 60, multiply times 2pi

that can be pi over 30

so the range is [6.67pi to 15pi]