: Can a bullet fall down vertically if shot from the back of an airplane with the same speed ?


Let’s say that an airplane is going at 1200mph, and you have a gun that supposedly fires bullets at 1200mph, there is another airplane tailgating you and you decide to shoot it from a window in the back of the airplane, is it true that the bullet will not hit the airplane but instead fall down vertically with no force ?

This is purely hypothetical

Edit : I remember getting this idea when I was in 8th grade, about when 2 forces have the same intensity and opposite directions they get nulled ? I don’t remember that very well lol

In: Physics

yup, there’s a bunch of videos on youtube but with nerf guns and balls. i think there might be one with a cannon ball but i could be wrong.

edit: specifically with the plane scenario, yes that’s what would happen, unless the second plane is so near or low enough to fly into the bullet.

edit again: [soccerball, not cannonball](https://youtu.be/BLuI118nhzc)

The net speed of the bullet compared to the ground would be zero (well, 9.8 m/s^2 vertically), so from an observer on the ground, it would appear to fall vertically.

But, the second aircraft would be travelling towards a “stationary” bullet at 1200mph, which would be the same as a stationary plane being shot by a 1200mph bullet, if it hits.

Collision would depend entirely on the angle the bullet was fired, the distance between the planes, and the height of the second plane.

It is true that the bullet will fall vertically as the forces (speed of the plane and speed of the bullet) cancel each other since they are equal in opposite direction. At least it would be true for an immobile bystander (here is a video from Mythbusters demonstrating it: [video](https://youtu.be/BLuI118nhzc))
But the plane that is tailgating you is still moving at 1200mph and will hit the bullet with the same force as it would have if both planes were immobile (approximately I’m not sure or is exactly the same). It’s just that it’s the plane which is moving instead of the bullet.

Actually, yes. But the plane tailgating you would still be going at 1200 mph and thus get struck by the bullet with that speed. The bullet wouldn’t fall down far enough in that time.

A bullet always fall down vertically at the same speed independent of its back- or forward speed. If you move at the same speed as the bullet, it will always appear to be just falling down vertically with no apparent horizontal movement. However, it will have energy.