Angular Kinetics Flashcards
Sugma
Angular Kinetics
Concerned with rotational around an axis
Angular Momentum
A measure of the amount of angular motion possessed by a rotating body
Angular Momentum Equation
Moment of Inertia x angular velocity
Moment of inertia
The resistance of a rotating object to change its state of motion
Angular Velocity
The speed of rotation- can be altered by changing MOI as they have an inverse relationship
Relationship between A velocity and moment of inertia
- Have an inverse relationship
- Velocity can be altered by changing the moment of inertia
Explain moment of inertia when in a tight tuck
If the mass of an object is distributed close to the axis of rotation, the MOI is small and it is easier to rotate the object
Explain moment of inertia when in a loose tuck
As the mass of an object moves further away from the axis of rotation, the MOI increases and rotation becomes harder
Equation for MOI
Mass of object x Radius of rotation
How to change moment of inertia
increase or decrease mass/ distribution of mass
When is mass a factor
Only when you can change mass prior to rotation
Radius of rotation
How the mass of the object is distributed about the axis of rotation
When does distribution of mass decrease MOI
when its closer to axis of rotation ie: top of raquet
Conservation of angular momentum
a rotating body will continue to turn about an axis of rotation with constant angular rotation unless an external force is applied to it
Eccentric force
a force that acts outside an objects centre of gravity, causing the object to rotate as well as move in a straight line (angular and linear motion)
eg of eccentric force
basketball free throw, putting back spin on the ball
concentric force
Force applied to produce linear motion, eg hitting a flat serve in volleyball
Torque
The turning effect created as a result of force being applied to an object outside its axis of rotation
Formula for torque
size of the force x moment arm
Moment arm
the distance between where the force is applied and where the torque (turning effect) occurs
how to increase/decrease torque
Increase/decrease force applied
Increase/decrease length of moment arm
explain torque in terms of a door
If you push a door near the hinges(where the torque is created) the moment arm is small and means less angular rotation is achieved when the same amount of force is applied
Force couples
two equal but oppositely directed forces that cancel out linear motion and only produce angular motion
