we can use v=u+at when value of 3 things are given then only we can find the value of the 4th thing.
we can use s=ut+1/2at^2 when value of 3 things are given then only we can find the value of 4th one.
we can use 2as=v^2-u^2 when the value of 3things are given and then you can only find out the value of the 4th one.
the motion of an object moving at uniform acceleration can be described with the help of these three laws of motion.
i hope that this will help u.............^_^