Does a bullet fall at the same speed when dropped as when fired out of a gun?

Question

My friend simply does not believe that gravity affects both bullets the same way, etc...
I've told him that, (allowing for human error, ok,) a bullet fired level and a bullet dropped from the same height at the same time will hit the ground at the exact same time. Forward velocity has no effect on gravity's pull. He simply doesn't believe me no matter what I say.
How about some input here? Send answers to:
mmfoud@yahoo

Answer 1

If you neglect the effects of drag, lift, spin, heating, topography, curvature of earth, etc. etc., and if the gun is positioned horizontally, they'll fall at the same rate.

The easy way to see this is to imagine that the gun fires bullets really really slowly. Then it's almost like pushing the bullet off a table with your hand. Use a stopwatch and you'll see that no matter how hard you push something off the edge of a table, it'll hit horizontal ground at the same time.

Once you see that in action, you can extrapolate it in your head to a bullet flying thousands of feet per second. Some people actually need to see things visually before they are convinced.

Answer 2

Gravity always produces the same force no matter if the object is moving. If the ground was level and a gun, rifle, was fired parallel to the ground, at the instant the rifle was fired, another object was dropped from the same height as the bullet's height in the rifle, they would be some distance apart but would hit the ground at the same time. I'm an engineer and this is basic physics. I won't go into the math of it but unless the bullet had wings and was affected by a lift due to it's velocity they would fall at the same rate.

Answer 3

I'm with your friend on this one...I cant imagine how a bullet dropped out of someones hand from 20 stories up, could hit the ground at the same time as a bullet fired straight down from 20 stories up. isn't the whole, "everything that has an action have an equal and opposite reaction" thing taken into consideration in this? Meaning, not only is gravity working on pulling the fired bullet to the ground (which is all thats acting on the dropped bullet), the force of the explosion would also act on propelling the fired bullet towards the ground faster.

It doesnt sound like it would make any sense to me that they would fall at the same rate and hit the ground at the same time...But, maybe thats why I'm don't get paid the big bucks.

Maybe you should ask the "Mythbusters"

Answer 4

one thing though.

This is in atmosphere, on earth.

If you were on the moon, a bullet fired with an orbital velocity would drop as the moon curved, if fired fast enough, so that the bullet would not drop, it would orbit the moon, (barrint things like hitting the side of a crater. While the other dropped.

But that's really fast, I forget the exact velocity just now.

And the poster who talked about 20 stories up.. The gun is fired at level, not the ground. They hit the ground at the same time. One bullet goes straight down, falling, the other curves down, fired at level.

I've had some sniper training. This is a fact.

Falling at the same speed is kind of a misnomer. The vertical component of the speed is the same. But for one the horizontal component of it's travel vector is 0, the fired one's horizontal component is like a few thou feet per second, horizontally, depending on the specific weapon and caliber.

This was a good question.

Gallileo wrestled with this at Pisa, many centuries ago.

Answer 5

You are correct, your friend just is not informed. Have him calculate what would cause "gravity" on the bullet. Explain to him all of those calculations, none change when the bullet is going forward - assuming no elevation to the trajectory from the start - so logically, if falls at the same rate - but not to the same spot, obviously. It also assumes the fired bullet doesn't hit something in its path that would affect it.

Answer 6

Vertical speed is the same irrespective of the horizontal velocity... a bullet fired from a gun stationary in respect to the ground will hit the ground at the same time as a bullet just dropped.

Answer 7

You're absolutely right. From the moment the bullet fired from the gun leaves the barrel, it falls at the same rate as one dropped from the same height at the same time. The fired bullet will go farther, but will strike the ground at the same time as the dropped bullet.

Answer 8

For all practical purposes your correct; however the spin of the bullet does create some deviation in it's flight. The heat created by projectile will also change the coefficient of drag, vertical, not horizontal, but it is very very very Minuit. Some people claim that this can be dramatic but, like I said, for all practical purposes the should fall at the same rate.

Answer 9

gravity acts the same way on both bullets, giving them the same downward acceleration and making them strike the ground at the same time if the bullet is fired horizontally over level ground.

Answer 10

It truly depends on the way you hold the gun. If you angle the chamber at a downward angle, it would push the spent cartridge out at a faster rate than gravity. However, if someone were to hold the gun right side up, it would first rise, and then peak and fall at the same rate as dropping a spent cartridge.