The analysis of ac circuits uses a rotating vector called a

Phasor

Explanation:

A phasor is usually referred to as a rotating vector which has scaled lines. A vector quantity is one which has both magnitude and direction.

Since a phasor is also a vector quantity it has the magnitude and direction in the form of quantity and displacement. The quantity and displacement are usually measured in a counterclockwise direction.

Phasors is used in the engineering world to establish relationships between AC quantities and the parameters such as current and voltage etc.

when insulating materials rub against each other, they may become electrically charged . electrons , which are negatively charged, may be 'rubbed off' one material and on to the other. the material that gains electrons becomes negatively charged. the material that loses electrons is left with a positive charge.