Aerial and Rotational Motion

Question 1

what is angular momentum?

Answer 1

Quantity of our rotational motion

Question 2

what is moment of inertia?

Answer 2

Resistance to rotational motion

Question 3

what is angular velocity?

Answer 3

Rate of our rotational motion

Question 4

aerial motion?

Answer 4

• Many sports have an aerial phase
• During flight, the path of the CM is fixed
• ‘Rotation’ is the only thing we can control

•Segments can be repositioned around CM
▫e.g. Fosbury Flop
▫e.g. ‘Cheating’ a vertical jump

Question 5

Resistance of rotational motion?

Answer 5

•Inertia = resistance to motion
▫Mass is our usual (linear) measure of inertia

•When considering rotation, moment of inertias a measure of a body’s resistance to motion

Question 6

moment of inertia?

Answer 6

If more mass is closer to an axis of rotation, it is easier to alter rotational motion of a body

•We cannot change our mass but we can redistribute it relative to the centre of rotation

The greater the distribution of mass around the centre of rotation the greater the moment of inertia

Question 7

what is equation of angular momentum?

Answer 7

Angular momentum = moment of inertia ×angular velocity: H = I·ω

Angular momentum is constant during flight…

Question 8

conservation of angular momentum?

Answer 8

When gravity is the only external force (as is the case when we are airborne), angular momentum (H) is conserved

Angular momentum is determined at take-off…

…therefore if moment of inertia (I) decreases…

•…angular velocity (ω)must increase

Question 9

Twisting, how can we create it?

Answer 9

How can we create twist?

•Contact twist
▫Create rotation about an axis before take-off

•Aerial twist
▫Asymmetrical movements
Arms
Hips