Looking for guidance on the following:

I need to calculate the Force needed in order to move a given mass over a known distance, in a known amount of time.

let's say:
m = 0.5 Kg
d = 5mm or 0.05m
t = 500ms or 0.5s

Initially I had thought I could use the equations of linear motion, namely s = voT + 0.5a(t^2) to calculate the needed acceleration, since I know displacement and time. Then use that acceleration into F=ma to calculate the force, but the results don't seem to make sense. Any inputs?