Answer:
1.0 x 10^-3 m
Explanation:
1mm = (1/1000) m = 0.001m = 1.0 x 10^-3m (because to get 1.0, you have to movi the decimal point in the "0.001" three spots over to the right)
Your answer should be metal
Taking right movement to be positive means leftward movement is negative.
Hence we have a deceleration of



Using this 'suvat' equation

we can determine the initial velocity



Hence the initial velocity is 13.0 meters per seconds