Four identical point charges (+6.0 nC) are placed at the corners of a rectangle which measures 6.0 m×8.0 m. If the electric potential is taken to be zero at infinity, what is the potential at the geometric center of this rectangle

Ablue car pulls away from a red stop-light just after it has turned green with a constant acceleration of 0.5 m/s 2 . a green car arrives at the position of the stop-light 6.5 s after the light had turned green. if t = 0 when the light turns green, at what time does the green car catch the blue car if the green car maintains the slowest constant speed necessary to catch up to the blue car? answer in units of s.