THE RADIAN
 

The standard unit of plane angular measure is the radian (rad). It is the angle subtended by an arc on a circle whose length, as measured on the circle, is equal to the radius of the circle as measured on a flat geometric plane containing the circle. Imagine taking a string and running it out from the center of a circle to some point on the edge and then laying that string down around the periphery of the circle. The resulting angle is 1 rad. Another definition goes like this: One radian is the angle between the two straight edges of a slice of pie whose straight and curved edges all have the same length r (Fig.1). It is equal to about 57.2958 angular degrees.

Fig. 1. One radian is the angle at the apex of a slice of pie whose straight and curved edges all have the same length r.

مواضيع ذات صلة

THE TESLA

THE WEBER

THE HENRY

THE FARAD

THE HERTZ

THE SIEMENS

THE OHM

THE VOLT

THE COULOMB

THE WATT

THE JOULE

THE NEWTON