The motion is along straight line . If the object hans not reached the maximum height and
is not returning back before t= t1, then distance and displacement are same.
If the objecte reaches maximum height before t = t1 , then displacement and distance are not same.
In this later case, distance travelled equals sum of distance from staring point to maximum height and
the distance travelled during backward motion.
In the later case , displacement equals difference between final position and initial position.