Alright , its very simple.So basically the body is falling down at uniform speed , allow me to break it down for you.
At t=0 , speed=0
at t=1 , speed=0+9.8=9.8
at t=2 , speed=9.8+9.8=19.6
at t=3 , speed=19.6+9.8=29.4
at t=4 , speed = 29.4+9.8=39.2
so , at t=5 , speed = 39.2+9.8=49
its in uniform motion , bc its speed is changing at a uniform rate of 9.8 m/s each second.
