MEJIA, Mirianiel Monsanto, Hermie Joy Masuhay, Lysa Nisperos, Crizyl Mae Tan, Dennis Roldan Tillo, Alaizalyn

A rotation is a circular movement of an object around a center (or point) of rotation. A three- dimensional object rotates always around an imaginary line called a rotation axis. If the axis is within the body, and passes through its center of mass the body is said to rotate upon itself, or spin. Revolution referred to as orbital revolution for clarity, is used when one body moves around another while rotation is used to mean the movement around an axis.

Rotational speed (sometimes called speed of revolution) tells how many complete rotations (i.e. revolutions or cycles) there are per time unit. It is therefore a cyclic frequency, measured in hertz (revolutions per second) in the SI System. The units revolutions per minute (rpm or 1/min) are more common in everyday life.

Centripetal force (from Latin centrum "center" and petere "to seek") is a force that makes a body follow a curved path: it is always directed orthogonal to the velocity of the body, toward the instantaneous center o curvature of the path.

The two forces are equal in magnitude and opposite in direction. The centrifugal force does not act on the body in motion; the only force acting on the body in motion is the centripetal force.

Centrifugal force (from Latin centrum "center" and fugere "to flee") can generally be any force directed outward relative to some origin. More particularly, inclassical mechanics, the centrifugal force is an outward force which arises when describing the motion of objects in a rotating reference frame. Because a rotating frame is an example of a non- inertial reference frame, Newton's laws of motion do not accurately describe the dynamics within the rotating frame.

The simulation of the pull of gravity aboard a space station, space colony, or manned spacecraft by the steady rotation, at an appropriate angular speed, of all or part of the vessel. Such a technique may be essential for long-duration missions to avoid adverse physiological (and possibly psychological) reactions to weightlessness.