Arifle bullet is fired horizontally at the same instant another bullet is allowed to drop from rest at the same height. which bullet strikes the earth first?
a) the bullet from the rifle.
b) the bullet allowed to drop.
c) both strike at the same instant.

c) Both strike at the same instant.

Explanation:

As the gun has fired the bullet horizontally so there is only a horizontal velocity component which plays no role in the falling of bullet down to earth. The only force acting on the bullet vertically downward is the force of gravity. As there is no vertical velocity so the bullet will fall downward as some one has dropped it from rest from the certain height. Both of the bullets are falling only under the action of gravity. So in this way we can say that both the bullets will strikes the earth at the same time.