# Rotational motion

1. Nov 9, 2016

### SDTK

1. The problem statement, all variables and given/known data

this is a question just to help with my understanding: ....

when Torque (kg m^2/s^2) and the Moment of Inertia (kg m^2) are known and used to find angular acceleration, .... T(net)/I, are the units for the resulting acceleration rad/s^2

Thanks :-)

2. Relevant equations
$\tau = I \alpha$

3. The attempt at a solution
Example:
t = 12 kg m^2/s^2
I = 3.00 kg m^2

angular acceleration = torque/I = 12 kg m^2/s^2 / 3.00 kg m^2 = 4 units(?) / s^2

Last edited by a moderator: Nov 9, 2016
2. Nov 9, 2016

### Staff: Mentor

Yes. Angular acceleration is given in radians per second squared $(rad/s^2)$.

The radian is sort of a "unitless unit" that appears and disappears as required when working with angular quantities. It's based on a ratio of lengths from the unit circle, where an angle is defined via the arclength along the circle divided by the radius length. It serves to distinguish a quantity as being angular in nature.

3. Nov 9, 2016

### SDTK

thank you! :-)

4. Nov 9, 2016