ROTATION

When an object that can rotate needs to be rotated,
it has a rotational inertia fighting rotational acceleration upon its own axis.
Thus, if it is already moving, then its rotational inertia resists
speeding up or slowing down oon its turning axis.
The farther away mass is from the center,
the higher the rotational inertia will be.

NOTE: Rotational inertia is the rotational analog of mass.

The distance from the axis that the object is rotating on,
and the direction of force that is rotating the object is called R.
The product of R and the force being used on the rotating object is called torque.

NOTE: Torque is the rotational analog of force.

Angular velocity is merely the rate that the object rotates,
and is measured in revolutions per second.
Angular momentum is the product of rotational inertia
and angular velocity.
When there are no torques acting upon a rotating object, angular momentum is conserved.
So, if the rotational inertia of an object decreases, then the turning rate will increase.
Also, when angular momentum decreases, rotational inertia decreases.
This means that the slower an object is turning, the more resistance it has to speed up or slow down.

NOTE: Angular momentum is the rotational analog of linear momentum.

Complex Mechanics Home | | Phun Physics Home