A particle is traveling between two charged plates, separated by a distance d=1.5 mm, with an initial velocity of 18.5x104 m/s to the right as shown. It is observed that the particle is slowing down as it approaches the right plate. Assume that it is known that the particle is either an electron or a proton; which is it, you ask? You need to determine the type of particle first and then calculate the speed of the particle just as it arrives at plate on the right. Do NOT use scientific notation. Enter your answer as a decimal or whole number.