Question

A centrifuge accelerates from rest up to 20,000 rpm in 30.0s

a) What's the average angular acceleration?

b) How many revolutions did the centrifuge make during that 30.0s?

Answer 1

.a
Angular velocity and angular acceleration use radians to measure angle, and there are 2? radians per revolution, so

(20000 rev/m=333.3 rev/sec) * (2? rad/rev) = 2093.1 rad/s
that's the final angular velocity. The average angular acceleration is the change in velocity over the change in time:

2093.1 rad/s / 30 s = 69.7.6 rad/s^2

b)(x rev/sec) * (2? rad/rev) =y

69.7.6 rad/s^2=y / 30 s

y=2093.12

(x rev/sec) * (2? rad/rev) =y

(x rev/sec) =2093.12/(2*3.14)

(x rev/sec) =333.2