How long does it take a car travelling at 80 m/s to decelerate to 18 m/s with an acceleration rate of -16m/s?

Two point charges are separated by a certain distance. how does the strength of the electric field produced by the first charge, at the position of the second charge, change if the second charge is doubled? a. the field does not change b. the field strength decreases by half. c. the field strength doubles d. the field strength quadruples