[bluedlightning]

Watched on Mythbusters last night the old debate about if a bullet droped at the same time one is fired will they hit the ground at the same time? Answer is YES. The did the experiment with a Colt 1911A1. The gun being level and rigged to fire remotly from a ransom rest the bullet from it hit the ground .32 milliseconds after the one droped from the same hight. It just goes to prove that Newton was right. Way cool experiment. :up:

[george parsons]

its interesting but i can see why they took on this myth....i still find it hard to believe that the fired bullet did not fall faster.

but if myth busters said its so i believe them.....its just hard to believe.

[PreserveFreedom]

I am surprised that the twist on the fired bullet didn't effect the drop and keep it in the air longer.

[gmcfixer]

Well guys, we watched that yesterday too. And before they started I said that they would hit at the same time (or close enough) because of simple physics.

Think of it this way, what causes a bullet to drop. One thing and one thing only, gravity. When we adjust our scopes for bullet drop we say that it drops "X" amount at a distance of say 100 yards. A physics minded person will tell you that we are actually adjusting for the amount of distance traveled after dropping a certain amount. Now I realize that sounds crazy but that is what actually happens and it important to understand in this case because after the bullet leaves the barrel the only thing that practically effects it as far as drop is gravity. Everything else effects the forward movement. Keep in mind this is assuming everything else is equal between the dropped bullet and the fired bullet, that the barrel is parrallel to the earth and that the timing of the firing and the drop are prefect. Make sense?

Dave Z

[Sir Knight]

Gravity pulls everything down at the same rate. So, unless a bullet was fired upward and working against gravity briefly, it will hit the ground at the same time as a dropped bullet.

[Zen900]

Dumb question:

now suppose the same test is done only this time there is twice as much propellant in the case of the bullet. Wouldn't it travel farther? If so does it stay in the air longer? Keep in mind I'm not disputing Newton. I'm sure he won a lot of bets with his theory.

[Popeye]

Dumb question:

now suppose the same test is done only this time there is twice as much propellant in the case of the bullet. Wouldn't it travel farther? If so does it stay in the air longer? Keep in mind I'm not disputing Newton. I'm sure he won a lot of bets with his theory.

Yup. The bullet will travel farther. It will also be moving faster. Twice as much time in the air, twice the speed.

Gravity is the constant.

[Sir Knight]

Actually, no. The time in the air will be the same because, as you said, gravity is the constant and will pull the bullet down at the same rate but the distance traveled will be greater.

[gmcfixer]

I have to agree with Alan, the bullets flight time will not change as long as everything else remains constant. The flight time is the same but the distance is increase because it is able to fly further in the same amount of time.

Dave Z

[Popeye]

I said it wrong. But you get my point.

[gmcfixer]

I said it wrong. But you get my point.

I kind of figured you meant twice the distance for the time in air rather than twice the time. Your ending it with gravity is a constant said you knew what I had said.

Dave Z

[Stevejet]

You're all a bunch of mad scientists if you ask me. This discussion reminds me of the "witch trial" in Monty Python's Holy Grail where the villagers argue thru deductive logic, led by the village genius, wether the suspect, adorned with a carrot tied to her face as a nose, should be subjected to the dunking pond to determine if she is a duck, a piece of wood, little tiny, teeny rocks or a witch, depending on if she floats!

[gmcfixer]

I see no connection between the two, have a nice day

Dave Z

[BigSwede]

The extra .32 milliseconds might have been due to curvature of the earth...just a little farther and you're in orbit!

[Seamaster]

I would think if performed in a vacuum, the times would be alot closer, also think the curvature of the earth adds a little bit also. Pretty dang cool experiment anyway.

[Zen900]

I finally see now. Gravity is the constant. I remember being absolutely astounded when I first heard that theory. I have 60 hours of college math but never understood a thing they taught me. I usually cheated on the tests. I was better at hiding formulas than calculating math.

[Urzandowski]

Another force acting on the bullet is drag. I assume the Myth Busters are in San Francisco. San Fran is perty much sea level, where the air is the thickest. Im wondering if youd get the same results if the bullet were fired at say 16,000 feet. But then at 16,000 feet the drag and gravity would be a constant on both bullets. Ok nevermind. Ow this thread makes my brain hurt.

[texasalien]

Watched on Mythbusters last night the old debate about if a bullet droped at the same time one is fired will they hit the ground at the same time? Answer is YES.

OK, I can accept this if the barrel is not pointed downward at the time the bullet is fired. :D

[shoey]

Thye slight difference is indeed due to air resistance. The law only holds true in a vaccum...but it is cool....we tested it in high school by flicking a penny off a table and dropping one at the same time.....if coordination was right it was close

[gmcfixer]

Thye slight difference is indeed due to air resistance. The law only holds true in a vaccum..

Describe it as air resistance or drag or anything else, it doesn't matter. The only force pulling the bullet to the ground is gravity. Bullets of the same weight are effected equally by gravity.

Dave Z

[shoey]

True....in ballistic trajectory, the air resistance counters gravity for a little while, hence the arc and therefore the discrepency in fall time.

[gmcfixer]

True....in ballistic trajectory, the air resistance counters gravity for a little while, hence the arc and therefore the discrepency in fall time.

In physics air resistance effects the forward motion, any air resistance on the downward movement is a constant.

Dave Z

[Redrum]

In physics air resistance effects the forward motion, any air resistance on the downward movement is a constant.

Dave Z


That is true if you performed the experiment in normal air. The only way both bullets will hit the floor at the exact same time is if the entire experiment is performed in a vacuum to eliminate any air resistance, whether vertical due to drag, or horizontal due to gravity or air turbulance. Also, the time for the bullet to drop is calculated at the moment it leaves the barrel. Velocity has no effect on how long the bullet stays in the air. (the barrel must be parallel to the ground). It will stay in the air the same time if it fired or dropped. Gravity is constant at 32 ft/sec/sec. the bullet weight is constant throughout the flight (ignoring any residuals left on the lands and grooves). See explaination here. http://74.125.95.132/search?q=cache:GvxOlJN7BwgJ:tutor4physics.com/example.htm+physics+bullet+problem&cd=1&hl=en&ct=clnk&gl=us