Biomechanics - Angular Motion & Projectile Motion Flashcards
What is Angular Motion?
- Refers to rotation
- Involves movement around a fixed point or axis
- Can involve the whole body (somersault) or a body part (such as the arms in a cricket bowling action)
When does Angular Motion occur?
- When a force is applied outside the centre of mass
- An off-centre force (eccentric force) is applied
Where is the Transverse Axis?
Running side to side across the body
Where is the Sagittal Axis?
Running from front to back
Where is the Longitudinal Axis?
Running from top to bottom
What is the rotational consequence of a force?
- Torque
- Moment of force
What is a RADIAN?
The unit of measurement for angles
What is Angular Displacement?
- The smallest change in angle between the start and finish points of a rotation
- Measured in degrees OR radians (1 radian = 57.3 degrees!)
What is Angular Velocity?
- The rate of change of angular displacement
- The rotational speed of an object and the axis about which it rotates
- Angular displacement (rad) / Time taken (s)
What is Angular Acceleration?
- The rate of change of Angular Velocity
- Change in angular velocity (rad/s) / Time taken (s)
- Measured in radians/second/second
What does Newton’s First Law of Angular Motion state?
“A rotating body will continue to turn about its axis of rotation with constant angular momentum unless an external rotational force (torque) is exerted upon it”
What does Newton’s Second Law of Angular Motion state?
“The rate of change of angular momentum of a body is proportional to the force (torque) causing it and the change takes place in the direction in which the force (torque) acts”
What does Newton’s Third Law of Angular Motion state?
“When a force (torque) is applied by one body to another; the second body will exert and equal and opposite force (torque) on the other body”
What is Moment of Inertia?
Measure of resistance of an object to rotation, and the desire of a body to continue to rotate once it has been set in motion
