You can google it. I've found this: http://www.ugrad.math.ubc.ca/coursedoc/math101/notes/applications/velocity.html
But if you don't want to read, it's:
p(t) = x(0) + v(0)*t + (1/2)at^2
where
- p(t) = position at time t
- x(0) = the position at time zero
- v(0) = velocity at time zero (if you don't have a velocity, you can ignore this term)
- a = the acceleration
- t = your current itme
