-identifies an electric charge
-it can identify its polarity (positive or negative) if you compare it to a charge that you already know
-can identify the magnitude of a charge (how big of a charge it is)
If the vertical component is 29.6 m/s down, and the horizontal component
is 54.8 m/s parallel to the surface, then the magnitude of the slanty vector is
√(29.6² + 54.8²) = √(876.16 + 3003.04) = √3879.2 = 62.28 m/s .
That's 139 mph ! Wow !
