4.2 Anglular Motion Flashcards
Define angular motion
Movement around a fixed point
What are the 3 axes of rotation?
Transverse - runs from side to side (somersault)
Sagittal - runs from front to back (cartwheel)
Longitudinal - runs from top to bottom (ice skating spin)
Define torque
The rotational consequence of a force
What does torque cause?
Causes an object to turn about it axis of rotation, increasing the size of the force increases torque
How is torque calculated?
Force (newtons) x Perpendicular distance from fulcrum (m)
What is Newton’s first law for angular motion?
A rotating body will continue to turn about its axis of rotation with constant angular momentum unless an external, rotational force (torque) is exerted upon it.
What is Newton’s second law for angular motion?
The rate of change of angular momentum is proportional to the force (torque) causing it and the change that takes place in the direction in which the force (torque) acts.
What is Newton’s third law for angular motion?
When a force (torque) is applied by one body to another, the second body will exert an equal and opposite force (torque) on the other body.
What quantities are used in angular motion?
Angular displacement
Angular velocity
Angular acceleration
Define angular displacement
The smallest change in angle between the start and finish point of a rotation
Define angular velocity
The rate of change of angular displaceme
Define angular acceleration
The rate of change of angular velocity
What is 1 radian?
57.3 degrees
What does moment of inertia depend on?
Mass of body
Distribution of mass from the axis of rotation
How does mass affect inertia?
The greater the mass, the greater the resistance to change and therefore the greater the moment of inertia
