Question

Under what condition is the relation s=ut is correct

Answer 1

First equation of Motion:
V = u + at
soln.
Consider a body of mass “m” having initial velocity
“u”.Let after time “t” its final velocity becomes “v” due to
uniform acceleration “a”.
Now we know that:
Acceleration = change in velocity/Time taken
=> Acceleration = Final velocity-Initial velocity / time taken
=> a = v-u /t
=>at = v-u
or v = u + at
This is the first equation of motion.

Answer 2

if either of acceleration or time , is zero
then the relation
s=ut ( where s=displacement, u=initial velocity,t=time,a=acceleration) holds true
as the original formula is s=ut+1/2at^2
and as either a and t are 0 then it becomes s=ut
Hope I have helped you!