Rotational motion definitions Flashcards
Displacement
For a particle, it is the length and direction from the origin to the particle. It is a
function of time.
Velocity
The rate of change of displacement with time.
Acceleration
The rate of change of velocity with time.
It is also the second differential of displacement with time.
Angular Displacement
The angular motion travelled by a rotating object, measured in radians.
One full revolution of 360 ̊ is the same as 2π radians.
Angular Velocity
The rate of change of angular displacement.
Angular Acceleration
The rate of change of angular velocity.
Tangential Acceleration
The rate of change of linear (tangential) velocity.
Centripetal/Radial
Acceleration
The acceleration of an object moving in a circular path which acts towards the
centre of axis of rotation.
Centripetal Force
The unbalanced force acting on an object that has a centripetal acceleration.
It acts towards the centre of the circular path taken by the object and is
necessary to maintain circular motion.
Torque
A force which produces rotation about an axis. It is a vector quantity.
Inertia
An object’s resistance to change its motion.
Moment of Inertia
A measure of an object’s resistance to angular acceleration about a given axis.
It depends on the mass of the body and the distribution of its mass about a
given axis of rotation.
Angular Momentum
The momentum of a rotating object. It is a vector quantity.
Principle of
Conservation of
Angular Momentum
The total angular momentum before an interaction is equal to the total angular
momentum after the interaction, provided there are no external torques acting
on the objects.
Rotational Kinetic
Energy
The kinetic energy of a rotating body.
