A car starts from rest and accelerates at constant rate, in the first sec it covers a distance of 2 m. The velocity of car at the end of 4th sec is

Distance covered in nth sec  Sn=U+an−12       here initial velocity=U;  acceleration=a Starting from rest U=0; substitute in above equation  Sn=an−12   given In 1st sec  S1=2 ⇒2=a1−12 ⇒a=4 m/s2 Velocity at end of 4th sec  V=U+atV=0+44⇒V=16 m/s=final velocity at the end of 4th second