Newton's Laws Angular Flashcards
Newton’s First Law (Angular)
Law of Inertia (Angular)
Law of Inertia (Angular)
A rotating body will continue rotation unless acted on by an external torque. (Mass and velocity but in angular terms. Matters in terms of how we perform skills especially when moving quickly/has a lot of rotation.)
“Conservation of Momentum”
- Angular Momentum = I * ω
I = moment of inertia
ω = angular velocity
Moment of inertia
- Distribution of mass around the axis of roation
- Resistance of angular acceleration
- Angular momentum = I * ω
Moment of inertia decreases as a result of…
decreasing the radius but allows for high angular velocity.
Describe what is happening here:
Left: Low Moment of Inertia, High Angular Velocity
Right: High Moment of inertia, Low angular velocity
How does moment of inertia change the leg during running?
Sprinter wants to go faster you will want to decrease radius. Flex hip and knee to swing knee through to allow for them to start again quicker. Want rate to slow down when hitting the ground so you extend your leg.
Moment of inertia chages due to r, flexing knee changes r and makes moment of inertia less.
Rotational Analogue of Newton’s Second Law
Σ𝑇=𝐼𝛼
Shrink inertia allows to accelerate quicker.
More knee flexion allow for lower moment of inertia of the knee allows for the hip to accelerate the leg through.
Straighter (longer radius) is longer with a straight leg, larger moment of inertia due to radius from hip. Bent knee (shorter radius) easier to create turnover.
Rotational Analogue of Newton’s Third Law
For every torque applied by one body on a second, there is an equal and opposite torque exterted by the latter body on the former.
Torques will be equal within a joint but has affects later in the chain in other joints but in these joints will have there own torque.
