Question

a body starts moving from rest with an acceleration of 4 m per second square find its velocity after 4 seconds

Answer 1

v = at
v = 4×4
v = 16m/s

Answer 2

u=0 as body starts from rest
a=4m/s^2
t=4s
v=?
v=u+at
=0+4*4
=8m/s^2