Copyright © Michael Richmond.
This work is licensed under a Creative Commons License.

##
Radial and Tangential Quantities

- Radians are worth using because they make it very simple
to convert between angular and tangential quantities.
If one uses degrees, one must constantly go back to
"360 degrees equals one revolution, which is a distance
two pi times the radius ..."
- Given the angular velocity
**omega** of an object,
and its angular acceleration **alpha**,
one can calculate
tangential displacement s = R * omega * t
tangential speed v = R * omega
T
tangential acceleration a = R * alpha

- If an object moves along a circular path, but changes its
speed as it moves (slowing down or speeding up),
then it is NOT in uniform circular motion.
- It retains a centripetal acceleration (towards center of circle)
because, at any particular moment, it has some
tangential velocity, and
v^2
centripetal acceleration a = -----
c R

But it also has a tangential acceleration due to its change
in tangential speed; one way to express it is
tangential accleration a = R * alpha
T

Viewgraphs
Copyright © Michael Richmond.
This work is licensed under a Creative Commons License.