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Lesson 9 - Angular Motion - Coggle Diagram
Lesson 9 - Angular Motion
Angular displacement
It is the angle made by a body while moving in a circular path. Before we go any further into the topic, we have to understand what is meant by rotational motion. When a rigid body is rotating about its own axis, the motion ceases to become a particle. It is so because in a circular path velocity and acceleration can change at any time. The rotation of rigid bodies or bodies which will remain constant throughout the duration of rotation, over a fixed axis is called rotational motion.
The angle made by the body from its point of rest at any point in the rotational motion is the angular displacement.
Angular velocity: the rate of change of angular position of a rotating body.
SI units for Angular velocity: radians per second
Formulae for Angular velocity: ωf = ωi + α t
SI units for Angular displacement: radian (rad)
Formulae: Angular Displacement = θf-θi
Angular acceleration
Angular acceleration is measured in units of angle per unit time squared (which in SI units is radians per second squared), and is usually represented by the symbol alpha (α). In two dimensions, angular acceleration is a pseudoscalar whose sign is taken to be positive if the angular speed increases counterclockwise or decreases clockwise, and is taken to be negative if the angular speed increases clockwise or decreases counterclockwise. In three dimensions, angular acceleration is a pseudovector.
SI units: radians per second squared
Formulae:
α
=
Δ
ω
Δ
t
Linear displacement
SI Unit for linear displacement: metre [m]
Symbol: s
angular displacement
SI unit for angular displacement: radian (rad)
Symbol for angular displacement: θ
tangential velocity
SI unit for angular velocity: radians per second
Symbol for tangential velocity: s
tangential acceleration
SI unit for tangential acceleration: meter per sec square.
Symbol for tangential acceleration: at
angular acceleration
Si unit for angular acceleration: radians per second squared
Symbol for angular acceleration: α