# Measuring the Rotation Rate of the Table

The rotation rate of our table can be quoted in various units. The following are often used - period, revolutions per minute, or units of 'f', as described below:

1. The angular velocity of the tank, Ω , in radians per second

2. The Coriolis parameter (f) defined as f = 2Ω

3. The period of one revolution of the tank, τ, in seconds is τ = 2π/Ω

4. Revolutions per minute, rpm = 60/τ

Conversion table

Ω (rad/s) | 0 | 0.25 | 0.5 | 1 | 1.5 | 2
f=2Ω(rad/s) | 0 | 0.5 | 1 | 2 | 3 | 4
τ(s) | ∞ | 8π = 25. 1 | 4π = 12. 6 | 2π = 6. 3 | 4π/3 = 4. 2 | π = 3.14
rpm | 0 | 2. 4 | 4. 7 | 9.5 | 14.3 | 19.1

Note that on the 'big' table pictured above, the digital readout is the rotation rate in `milli-f': thus 1000 is a rotation rate of 1× f: the period of rotation is thus 12.6 s.