Angular Kinetics Flashcards
Why would a diver open up as they approach the water?
To slow down their angular velocity
To learn how body position affects motion we must examine what components?
Angular kinetics to examine the torques that affect rotational movements
What is a torque?
A force that produces rotation (movement of force). Also known as a moment or rotational force.
What are the 3 factors that a torque is dependent on?
The magnitude of the force
Point of application
Direction
What is the formula for torque? The units?
T=Fd
Units: Nm
What is d (perpendicular) in regards to torque?
(Moment arm) or the perpendicular distance between the line of action of the force and the axis of rotation
What is Newtons 1st Law? (For linear motion…)
Every body remains in a state of constant velocity unless acted upon by an external force.
What is the angular equivalent?
Every body remains in a constant rotational state unless acted upon by an external torque.
A system will continue to rotate with a constant ____ until acted upon by a _____.
angular momentum
momentum of force
A system will resist a change in its ______.
angular state of motion
What is the momentum of inertia?
Movement= dealing with rotation
Formula for Inertia?
I=mk2
What is (k) the radius of gyration?
The distance from the axis of rotation to where body mass is concentrated. (Angular equivalent of mass).
What happens when a body is more tightly concentrated
the radius of gyration will be smaller in the pike position
The moment of inertia affected by _____ and ______?
Body orientation
Segment orientation
What happens when the body is fully extended when measuring Inertia?
The radius of gyration will be larger in the layout position
What are the principal moments of Inertia? (Relative planes of Inertia).
Transverse planes
Sagittal Plane
Frontal Plane
Inertia is low in what plane of Inertia?
Transverse Plane
Moderate Inertia takes place in what plane?
Sagittal Plane
Inertia is highest in what plane?
Frontal Plane
What is Newtons Second Law?
The law of momentum and the law of acceleration. (Linear motion and Angular Equivalent).
Newtons Second Law: For Linear Motion for the law of momentum?
The rate of change of momentum of a body (or the acceleration for a body of constant mass) is proportional to the force causing it and the change takes place in the direction in which the force acts.
Newtons Second Law: The Angular Equivalent for the law of momentum?
The rate of change of angular momentum of a body is proportional to the torque (moment) causing it and the change takes place in the direction in which the torque (moment) acts.”
Newtons Second Law: For linear Motion for the law of acceleration?
A force applied to a body causes an acceleration of that body of a magnitude proportional to the force, in the direction of the force, and inversely proportional to the body’s mass.
Newtons Second Law: For Linear motion for the law of acceleration?
A net torque produces angular acceleration of a body that is directly proportional to the magnitude and inversely proportional to the body’s moment of inertia.
When an object rotates it has ________.
Angular Momentum= the quantity of motion
What is the formula for Angular Momentum?
(H)= moment of Inertia * angular velocity
H=Iw
What are the units for angular momentum?
Units: kg m2/s
According to Newtons 1st law, in the absence of an external torque, every system remains in what kind of state?
Constant rotational state
When the total angular momentum of the body is conserved, the ________ will affect how the system moves in the air.
Body Position
Independently moving the arms can shift the axis of rotation
What are Asymmetrical movements?
Compensatory movements
Initial Movement
What is a compensatory movement?
Kicking the legs forward to cause the body to rotate backwards.
What is an Initial Movement?
Swinging the arm at the shoulder joint to cause the whole body to rotate forward.
What is the local term when calculating Angular Momentum?
Examining the momentum of an individual segment of the system
What is the remote term when calculating Angular Momentum?
Examining the momentum of the entire system
In order to change the angular momentum of a system, we need to apply a _______ over a period of _________.
Torque
Time
Angular Impulse formula?
Angular Impulse= Torque* time
Units for Angular Momentum?
Units: Nms
For Linear Motion:
For every force applied by one body on a second, the second body applies an equal and oppositely directed force on the first
For Angular Equivalent:
For every torque (moment) applied by one body on a second, the second body applies an equal and oppositely directed torque (moment) on the first
