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Photoelectric Effect

I need help on this question, I don't know how to solve the last part of it.

Q5) If light of frequency 7.1x10^14 Hz is incident on the plate in question 4, what will be the maximum kinetic energy of the electrons that are emitted? What will be the velocity of these electrons?

Well first, the plate from question 4 I found to have a work function of 4.1x10^-19J

Then from E=hf I found the energy of the light to be 4.7x10^-19J

Then by deducting the work funtion from the energy of the light, I found the max kinetic energy of the electrons emitted to be 6x10^-20J

Now I have no clue. How am I supposed to find the velocity of the electrons emitted?