Preston is checking a voltage of a plug, and by mistake, instead of touching the black probe to the battery negative, he touches it to the metal case of the plug. what happens ?

The average time that it takes for the car to travel the first 0.25m is s. the average time to travel just between 0.25 m and 0.50 m is s. given the time taken to travel the second 0.25 m section, the velocity would be m/s.