# Calculate angle as a function of time

1. Feb 4, 2015

### LizardCobra

I need to calculate the angle of a rigid body under constant angular velocity as a function of time. The RPM of the body is known, so the angular velocity is ω=2πf. Therefore θ=ωt=[RPM]2πt/60. How can I calculate the angle so that it 'resets' after a full rotation?

2. Feb 4, 2015

### Svein

θ=ωt=[RPM]2πt/60 is correct. If you want the "basic" angle it is (θ mod 2π) = 2π⋅([RPM]t/60 mod 1) = 2π⋅frac([RPM]t/60) (frac means the decimal part).