Question

a body moving along a straight line at 20m/s undergoes an acceleration of 4m/s^2.After 2 seconds ,what will be its speed exactly after 2seconds?

Answer 1

u= 20 m/s
a= 4 m/s^2
v = u + at = 20 + 4×2 = 28 m/s

speed will be 28m/s

Answer 2

initial speed (u)=20
final speeed(v)=v
a=4
using first law of motion
v=u+at
v=20+4x2
v=28m/s