biomechanics Flashcards
what is angular motion
movement around a fixed point or axis. rotation of a body/limb. Occurs when a force is applied outside the centre of mass (COM)
how do we measure angular motion
- in radians (rads)
- each radian is approx. 57.6 degrees and there are approx. 6.28 radians in a circle.
angular distance and angular displacement are measured in radians, angular speed and angular velocity are measured in radians per second (rads/s)
what is moment of inertia
an objects resistance to changing form/state
what is angular velocity
the rate of change in angular displacement ( or simply the rate of rotation)
what is angular momentum
it is the quantity of angular motion possessed by a body. It is the rotational equivalent of momentum.
what is newtons first law
a rotating body will continue to run about its axis of rotation with constant angular momentum unless an external rotational force (torque) is exerted upon it.
what is newtons second law
the rate of change of angular momentum of a body is proportional to the force (torque) causing to and the change that takes place in the direction in which force (torque) acts.
what is newtons third law
when a force (torque) is applied by one body to another, the second boy will exert an equal and opposite force (torque) on the other body.
what are the 3 axis of rotation
- sagittal
- transverse
- longitudinal
what is the centre of mass
the point at which the body is balanced in all directions
what are the four factors that can affect the centre of mass
- number of contact points
- mass
- height of the centre of mass
- the centre line of gravity