Applying newtons laws to angular momentum Flashcards
(10 cards)
1
Q
IMPORTANT!!
A
- Angular motion is movement around a fixed point or axis.
- Angular motion occurs when a force is applied outside the centre of mass.
- An off centre force is called an eccentric force!!!
- When thinking about angular motion in the body you must consider the axis first!!
1. Transverse (somersault)
2. Sagittal (cartwheel)
3. Longitudinal (pirouette)
2
Q
Define torque
A
- Torque is a rotational force which causes the body to rotate around an axis.
3
Q
- Law of inertia
A
- A rotating object will continue in its state of angular momentum until an external rotational force (torque) is applied to it.
e.g. an ice skater will continue to rotate in the air until they land. Here the ground exerts an external force (torque) which changes their state of angular momentum. A decrease in angular velocity around their longitudinal axis.
4
Q
- Law of acceleration
A
- The rate of change of angular momentum of an object is directly proportional to the rotational force (torque) acting on it.
e.g. the faster a diver throws their head and arms forwards off a diving board, the greater their angular velocity will be around their transversal axis.
5
Q
- Law of action/ reaction
A
- For every rotational force applied there is an equal and opposite rotational force exerted.
e.g. when a diver throws their arms and head forwards and down, their legs will want to go backwards and up. This happens around the transversal axis.
6
Q
What is angular displacement?
A
- The smallest change in angle between the start and finish point (measured in radians).
- Radian= 57.3 degrees.
7
Q
What is angular velocity?
A
- The rotational speed of an object around the axis it is rotating.
8
Q
What is angular acceleration?
A
- The rate of change of angular velocity.
9
Q
How do you calculate angular velocity?
A
- Angular displacement/ time.
10
Q
How do you calculate angular acceleration?
A
- Change in angular velocity/ time.
