Suppose you are driving in a convertible with the top down at constant speed. you point a rifle straight upward and fire it. in the absence of air resistance, would the bullet land
(a) behind you,
(b) ahead of you, or
(c) in the barrel of the rifle?

(c) in the barrel of the rifle

Explanation:

When we are moving in a convertible with constant speed so as per inertia all the objects are moving with same speed as that the speed of convertible.

So here we can say that bullet when shot from the rifle then its speed is same as that of convertible in horizontal direction

So here we can say that if air friction is absent then bullet will move same horizontal distance as the distance moved by you in the convertible

so after it it will reach again at the same position then the displacement of you and bullet is same in horizontal direction so we can say that correct answer will be

(c) in the barrel of the rifle

where are the vectors ?