Angular Motion Flashcards
Define Angular Motion
When a body (or part of a body) moves in a circle or part of a circle about an axis of rotation
Define an Axis of Rotation
An imaginary line about which a body or part of body turns
What are the 3 axes of rotation?
Longitudinal Axis, Frontal Axis and Transverse Axis
What is the Longitudinal Axis and what form of rotation occurs here?
From the head to the foot of the body. Rotation around it causes a twisting action
What is the Frontal Axis and what form of rotation occurs here?
From the front to the back of a body. Rotation around it causes a ‘cartwheel’ action
What is the Transverse Axis and what form of rotation occurs here?
From the left to the right side of the body. Rotation around it causes a ‘somersault’ action
How is Angular Motion created?
By an eccentric force which passes outside the centre of mass or axis
What is the Moment of Inertia and how is it calculated /measured?
Reluctance of a body to change its state of angular motion or rotation - sum of the mass x the distance of the mass from the axis of rotation squared - kilogram metres squared (kgm squared)
What is Angular Velocity and how is it calculated /measured?
The rate of spin in a particular direction or angular displacement per unit of time - Angular displacement ÷ time - Radians per second (rad/s)
What is Angular Momentum and how is it calculated /measured?
The amount of angular motion of a rotating body - moment of inertia x angular velocity - kilogram metres squared per second (kgm2/s)
What factors affect the moment of inertia?
Mass and the Distribution of mass about the axis of rotation soothe closer the mass of the body is to the axis of rotation, the smaller the moment of inertia
What is the Angular Analogue of Newton’s first Law of Motion?
An object will continue to rotate with constant angular momentum unless acted upon by an external torque
What is the Law of conservation of angular momentum?
An object in flight is NOT acted upon by external torques, so angular momentum is constant. This is the law of conservation of angular momentum
