The S.I. unit of g is :

1. m s^-1
2. m s^-2
3. cm s^-1
4. cm s^-2

A body is projected vertically upward with an initial velocity u. If acceleration due to gravity is g, the time for which it remains in air, is —

1. u/g
2. ug
3. 2u/g
4. u/2g

An object falling freely from rest reaches ground in 2 s. If acceleration due to gravity is 9.8 m s^-2 , the velocity of the object on reaching the ground will be —

1. 9.8 m s^-1
2. 4.9 m s^-1
3. 19.6 m s^-1
4. Zero