Angular Motion (Principles 6/7) Flashcards
What are the two Biomechanical principles associated with Angular Motion?
Principle 6: Production of Angular Motion (Torque)
Principle 7: Conservation of Angular Momentum
What does Principle 6 state and what does it mean?
“Angular motion is produced by the application of a force acting at some distance from an axis; that is, by torque.”
This means that Angular Motion is typically produced by a force at a distance from an axis.
Interpretation of Principle 6?
If an Off-centre (eccentric) force is applied, the body tends to rotate about it’s axis.
This effect is known as torque.
What are the three factors that affect the amount of generated torque?
1) Applied Force
2) Length of Lever Arm
3) Angle of Application
It’s easier to initiate rotation when the force is perpendicular to the lever arm.
What does Principle 7 state?
“Angular momentum is constant when an individual or object is free
in the air.”
What does Principle 7 mean?
Angular momentum is the product of the rate at which the athlete is rotating—or their angular velocity.
The resistance to Angular motion is known as “the moment of inertia”
The farther a body’s distribution of mass from the axis of rotation, the greater is the body’s moment of inertia.
What is an example of Principle 7 in action?
As a diver pulls their arms and legs close to their body, the diver can decrease their moment of inertia.
As the moment of inertia changes, angular velocity also changes—by speeding up.
As the diver approaches the water, they straighten out, which reduces the rate of rotation just before they hit the water.
What does the Law of the conservation of angular momentum state?
“THE TOTAL ANGULAR MOMENTUM OF A ROTATING BODY REMAINS CONSTANT IF THE NET TORQUE ACTING ON IT IS ZERO.”
A rigid spinning object continues to spin at a constant rate and with a fixed orientation unless influenced by the application of an external torque.
