Do heavier bullets drop faster than lighter bullets....

[GarandOwner]

:banghead: I give up on this thread, too many people reinforcing false ideas. IN AIR objects do not fall at the same rate, not because of gravity but because of AIR RESISTANCE. All of the references to basic physics is referencing an IDEALIZED problem (which means air resistance is neglected) In the real world air resistance acts on everything. This is most evident in the classic case of dropping a pound of feathers and a 1 pound lead ball, a feather is not as aerodynamic as a ball, so it falls slower DUE TO AIR RESISTANCE. Now we look at two identical bullets, bullets are made to be aerodynamic, so their ability to overcome air resistance is great. When you drop two identical bullets, one that is heavier than the other, the heavier bullet will hit the ground first. HOWEVER the difference in time is so small that it is not humanly possible to percieve the difference.


Say you have a 55gr bullet and a 230 gr bullet that are of the same shape and size and you drop them at the same time from 5 feet. Using the position function that includes air resistance, we get that the 230 gr bullet will hit the ground in .5570 sec whereas the lighter bullet will hit the ground in .5582 seconds that is a difference of .0012 seconds or 12 ten thousandths of a second. The human eye can not observe this small of a time. That is why it seems that they hit at the same time, the spread between times decreases as height decreases
(ie they hit closer together if you drop them from a smaller distance)

 

[Thernlund]

In the real world air resistance acts on everything.

In the real world of objects weighing what bullets do, it doesn't matter. Drop a .22LR and an M1 Abrams from a height of 6 feet and they drop at the same rate. You cannot measure the difference in drop rate. Not with your eyes, not with a stopwatch. Vertical air resistance has no meaningful effect.

No... meaningful... effect. Period.


-T.

 

[Guns and more]

Stationary objects also have inertia, but not nearly as much. Like a gyroscope, a fast moving bullet is much harder to move off course than is a stationary one.

AAAARRRGGGGuuuu. A gyroscope will fall just as fast as anything else.

 

[Guns and more]

Quote:
Drop a BB and a bwoling ball from the same height and both hit the ground at the same time.
Only for a little while.

If you dropped them both from an aircraft at several thousand feet it would be a different story.

The BB especialy if lead would actualy be denser and might actualy have a higher terminal velocity than the less dense bowling bowl, and as a result hit first, though I would have to double check that with the stats of the ball. Normaly the much larger sphere would have the advantage, but the bowling ball is made from much less dense material.

The bowling ball would of course have more energy when it hit because it is significantly heavier.


Now if both were made of of the same material, lead to keep it simple, the larger sphere would have a much higher terminal velocity, and the lead size bowling bowl would still be gaining significant increases in speed long after the lead BB approached its terminal velocity.


So they would not hit at the same speed. The lead bowling ball size sphere would hit far sooner while the slow BB was still falling, its air resistance reducing its increases of speed from the gravitational pull long before.
The difference would be greater the further up they were dropped from.

This does not really relate to the OP's question though from a bullet fired at traditional angles, merely to your comment.

Boy is there a lot of misinformation here!!!

 

[ryanl]

As far as vertical drop. If you drop a bowling ball and a golf ball from 15 feet in the air they hit the ground at the exact same time. Not so close the eye cant tell, but the same time. I have seen this experiment more than once, and seen the camera slowed down enough to say with certainty it is the same time. To me this means all objects regardless of mass accelerate at the same rate. I do belive if dropped from an airplane the golf ball however would reach its terminal velocity before the bowling ball, therefore the bowling ball would hit the ground first. Just a WAG, but not much different then some of the stuff I just read in this thread.

 

[gym]

as a bullet slows down it drops, therefore if one bullet regaurdless of weight slows down faster, it will start to fall faster.

 

[1911Tuner]

as a bullet slows down it drops, therefore if one bullet regaurdless of weight slows down faster, it will start to fall faster.

Forward velocity ain't gotta thing to do with vertical acceleration.

Technically, bullets must be fired and dropped in a vacuum in order to strike the ground at the exact same instant...assuming that the bullet is dropped at the exact instant that the fired bullet gets free of the muzzle.

But...

In the presence of an atmosphere, and assuming that both bullets come under the influence of gravity at precisely the same instant...the difference in elapsed time to reach the ground would be infintessimally small.

 

[GarandOwner]

In the real world of objects weighing what bullets do, it doesn't matter. Drop a .22LR and an M1 Abrams from a height of 6 feet and they drop at the same rate.

You cannot say this with absolute certainty, you would have to test it.... Finding it would not be hard to do, Stokes equated fluid resistance in the 1850's you don't need high tech fast cameras to tell, you just drop both into a viscous fluid and calculate each's coefficient of drag, then replace the density of the viscous fluid with the density of air and you could find the difference in each through air. To say that at small heights objects fall at the same rate, but not at larger heights is foolish and doesn't make sense. Look at it intuitively: Why do some objects move slower through air? Because of the opposing acceleration of air resistance. It is there from the instant the object starts moving through air. It is smaller at low velocities, which is why from a small height the difference can not be perceived, but an object that encounters less air resistance accelerates faster (and this will hit the ground faster) than one that encounters more air resistance, even over a short period of time. YES it is small, but it is still there

No... meaningful... effect. Period.

This is a matter of opinion, while I do agree that this little difference would not effect, or even show up in your groups, it is still there. So to you it is not meaningful, but to a physicist or mathematician that like things exact, it WOULD be meaningful to them. Regardless OBJECTS DO NOT FALL AT THE SAME RATE. That you can not dispute truthfully. Even if the difference is milliseconds between when two objects hit, there is a difference so to say that they hit at the EXACT same time is false. Nearly the same time, almost the same time, true. Yes it is picky wording, but that small wording is the difference between what is correct and what isnt

As far as vertical drop. If you drop a bowling ball and a golf ball from 15 feet in the air they hit the ground at the exact same time. Not so close the eye cant tell, but the same time. I have seen this experiment more than once,

If you could reference some of these I would love to see them. On a high speed camera it might be possible to see the difference, but since 15 feet isnt very high, it would still be very close. The difference at such a short distance is very small, but there is still a difference there. So to say they hit at the EXACT same time is not true. To say that all objects fall at the same rate and air resistance has no effect doesn't make sense, how to parachutes work then? Why does a feather fall slower than a nail? So what you are saying is air resistance only acts on SOME objects? That doesnt make sense either, so who determines which objects experience air resistance and which dont? Objects like spheres are aerodynamic, so they resist air resistance well, that is why it is hard to tell the difference in drop rates with them. While gravity acts on all things the same regardless of shape or size, air resistance does not.

I can see some people are set with their ideas even if they are incorrect, so I think it is pointless to try and keep arguing

 

[Sheldon J]

I think part of your confusion is you are assuming that a bullet with a larger frontal area will slow and drop faster than one one with a minimal balletic coefficient, which will have an effect on how fast they slow down once fired.

However as I said on my previous post... if they have identical flat trajectory, are fired at the exact same time, over a flat surface, and all else being equal except their mass, they will still hit the ground at the same time, and that is no myth

 

[Zoogster]

Boy is there a lot of misinformation here!!!

How do you figure?

The air resistance of a falling object is based on its surface area. The greater the mass for a given surface area the higher the terminal velocity it will reach.
The longer the object is falling the greater the difference between two objects with very different terminal velocities.

I could have phrased it with formula and kept it simple and brain dead, but some rambling that essentialy states the same thing is more fun.

You also stated

Bullets falling orient themselves sideways. Mythbusters did this trying to see if a bullet fired straight up had enough energy to kill someone under them. They built a tube with a moving air column and the bullets fell sideways at about 150 mph, no matter what caliber.

Multiple things done by mythbusters were wrong. In fact they did one of the greatest disservices to people that bought into thier falling bullet episode. They could not find most of the rounds fired into the air so they just tried to estimate and simulate it, but thier estimates were seriously flawed.

However just speaking of the "orient themselves sideways" myth, bullets often remain spin stabilized whe fired straight up and fall base first.
Bullets that do not stay stabilized tend to tumble. Most bullets from the side are not symetrical, the front is different than the rear. That means the air resistance effects one side greater than the other causing it to flip. So very few bullet shapes would fall sideways. Tumbling does slow falling rounds, while those that remain stabilized will achieve a much higher return velocity.

 

[kcshooter]

This has gotten stupid. There is so much good and bad info in this thread now that it can't be deciphered.
Galileo proved that they will fall at the same rate. They will hit they ground at almost exactly the same time. One will get further than the other based of energy and other forces, wind drag would fit in here. The rate that they slow down has nothing to do with the rate that they fall.

Don't take my word for it, I'm not a physicist, look it up.


http://www.pbs.org/wgbh/nova/galileo/expe_fobj_1.html

 

[GarandOwner]

In a real-life experiment, both balls would land at about the same time. (Friction from the air would change the result only slightly.)

From your reference kcshooter, note it says about the same time not exact same time and the reason is air resistance. As stated before, all things fall at the same rate in a vacuum, because gravity acts the same on everything. Air resistance does not act the same on all objects, it is dependent on size, shape, mass and velocity.

I think I need to bite my lip and just let this thread die........why am I so stubborn


Here is an excpert from something called "ask a scientist" two Dr's stated the same thing as I have multiple times in this thread:


http://www.newton.dep.anl.gov/askasci/phy00/phy00271.htm

The problem is that the shape of bullets are very similar and they are very aerodynamic so the difference in air resistance acting on them is so small that it can not be perceived by the naked eye, if you increased the height, it would be easier to see.

 

[kcshooter]

Yeah, but the air resistance being talked about thru this thread is resistance to forward travel, not downwards. And does it have to be exactly the same time, or is too close to be distinguished by the human eye close enough?

How much of a difference do you think there is in downward motion resistance from wind drag on, say a .223 vs a .308 dropped from 5 feet?? Enough to affect them to the point that one is actually going to land first? Doubt it.

Drop them both side by side. They hit at the same time. Fire them both side by side on a flat trajectory. They still hit at the same time. Forward motion does not affect this.

 

[Funderb]

I CANT STOP LAUGHING OH JEFUSS


this thread is ridiculous. is this really being argued?

 

[Ridgerunner665]

Velocity has nothing to do with how fast a bullet drops...it does have an affect on trajectory.

A bullet dropped from your hand and one fired from a gun...drop at ALMOST (meaning VERY, VERY close to the same) the same rate.

Heavier bullets drop faster...gravity makes sure of that....lighter bullets leave the gun faster, and travel farther faster...giving them their flat trajectory. The lighter bullets do slow down faster (less momentum)...

A simple test...drop a ping pong ball and a golf ball from the top of a building (the higher the better)...the golf ball will hit the ground first.

And a large part of the mass confusion on this thread is this...many of you have trajectory mixed up with drop....Trajectory is the bullets flight path...Drop is the amount the bullet drops without any correlation to the distance it has travelled

 

[GarandOwner]

Yeah, but the air resistance being talked about thru this thread is resistance to forward travel, not downwards.

If you read back, it is quite established that the velocity mentioned was downward velocity not horizontal

 

[-v-]

Will a larger (note: Not heavier) bullet drop slower then a smaller bullet?

Yes.

Will it drop appreciably faster then the more streamlined bullet? No, unless your shooting to such accuracy that a few nanometers difference in drop actually matters. Now if you're referring to POI, then yes, a slower bullet will drop faster then a fast one, because it has more time to drop then the faster bullet. But load up a light and heavy bullet to the same velocity, and interior ballistics (drag, etc.) and they will both drop the same exact amount.

 

[Thernlund]

We're a gun forum. Not a physics forum.

No... meaningful... effect.

I'm losing IQ points in spades just being near this thread.


-T.

 

[CrawdaddyJim]

This thread should have died at post 12.

Quote:
So the real test for this would be dropping a 55gr bullet and a 230gr bullet at the same time and seeing which one hits the ground first.
Well that one I can answer, they both hit at the same time.

I think some Italian guy figured this out back in the 1500s at some leaning tower in Piza Italy.

For a visual think of a spray of water from a sprinkler. The only difference is the distance from the head when they hit the ground.

Jim

 

[mr.trooper]

gravity stays the same. all object fall at the same speed.

 

[don]

Has anyone mentioned density? Assuming same shape,not size, two objects of the same density should fall at the same rate. Weight should be irrelevant as is horizontal velocity.

 

[btaylor73]

This thread has been an interesting one to read. I'm not meaning to stir the pot any more than it is, I just wanted to show an interesting thing that I saw on a vacation to Hawaii last year. On the USS Missouri I found this interesting sign mounted on their 16 inch gun mounts. What caught my attention was how fast the projectiles where moving. They where just as a bit slower than my .308 load at around 2700 fps. The interesting thing was the distance sometimes achieved with the monsterous rounds, 23 miles!!!
I know that my 308 would never come close to reaching 23 miles!
My conclusion has been, all things probably hit the ground at the same time when shot perfectly vertical, but as soon as the barrel starts rising the math gets too complicate. All I know is that my 308 doesn't shoot 23 miles

 

[Ridgerunner665]

Most average 50 BMG loads are also around 2,700 fps....

 

[Thernlund]

They where just as a bit slower than my .308 load at around 2700 fps. The interesting thing was the distance sometimes achieved with the monsterous rounds, 23 miles!!!

The angle of the shot and the weight of the projectile factor in. The angle, obviously, allows for a further shot. The weight causes the projectile to shed velocity slower. The net effect a much further shot.

All I know is that my 308 doesn't shoot 23 miles

It absolutely would if that little bullet weighed 2,200lbs.

http://en.wikipedia.org/wiki/16_inch_Coast_Gun_M1919

But that has no bearing on the (ridiculous) topic at hand. The .308 and the 16-inch rounds would both hit the ground at the same time when fired horizontally.


-T.

 

[jakemccoy]

I guess each person can come up with their own answers if everybody assumes different wind conditions. Let's assume a vacuum to keep this discussion under control. I'm obviously a little too late though.