Mainly there are two
types of motion; linear motion and non linear motion.
But some scientists believe that in space no object
moves in a straight line ( Non Euclidian mechanics). It
moves in curved paths although it seems to be a
straight line. They believe that straight line is a
very small part of huge curve!
In straight motion the moving body have
only one acceleration vector, but in curved paths it
has two acceleration vectors, the centripetal
acceleration (acts towards the center of curve) and
tangential acceleration (acts in the direction of the
tangents at every moment), and the total acceleration
is the vector summation of the centripetal and
tangential accelerations.
If we have a body rotating with uniform
velocity, we will notice its acceleration not equal
zero as in linear motion because there is a value for
the centripetal acceleration although the tangential
acceleration is equal zero. You can feel it if you was
in a car moving with uniform velocity and moving in a
curved path |