# Net acceleration in rotational motion

Net acceleration in rotational motion is $$\sqrt{a_t^2+a_c^2}$$ ($$a_t$$ and $$a_c$$ are tangential and centripetal acceleration respectively). Why isn't angular acceleration also considered?

• Angular acceleration around which axis? Dec 8, 2019 at 5:26

That's because angular acceleration is not the same as linear acceleration, angular acceleration is the rate of change of angular velocity, and acceleration is the ate of hange of linear velocity. The tangential acceleration is however related to the angular acceleration as $$a_t=r\alpha$$
When you have some acceleration vector $$\mathbf a$$ you can always write it in the form of component vectors in perpendicular directions. Now in 2 dimensional motion there are two components (say) $$\hat {\mathbf i}$$ and $$\hat {\mathbf j}$$ . In non uniform circular motion the acceleration vector can be broken into (out of many possible combinations) two components one tangential and the other centripetal.