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Physics question


AtomicCEO
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If you fire a bullet from a perfectly level gun barrel, and you drop a bullet from the same height as the gun, will they hit the ground at the same time?

 

Please ignore the curvature of the earth, or any other landscape variables. Assume a perfectly level ground surface.

 

 

Bonus physics question? Does rifling of the barrel affect this answer at all?

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Won't the elevation of the gun from the earth's surface be a determining factor? A perfectly level gun (oh how I hate that term, "gun", because a gun and a rifle are two different things) fired from the height of 5,280 feet above the earth's surface would surely take longer to expend it's forward energy and then fall to the surface than a gun 3 feet above the surface.

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am I firing the gun straight ahead?...
perfectly level gun barrel

 

Won't the elevation of the gun from the earth's surface be a determining factor?
drop a bullet from the same height as the gun

 

 

oh how I hate that term, "gun", because a gun and a rifle are two different things

I'll admit that I'm no gun expert, but aren't handgun barrels "rifled", meaning they are grooved to make the bullet spin?

Edited by AtomicCEO
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yes,no

 

That's what I thought.

 

But I didn't know if the force caused by spinning would affect it's lift/drop. I guess thats stupid because the force is going to be equal on top and bottom.

 

If anything, the spinning would help prevent the bullet from taking wild dives in any direction and stay on a straight path to hit at the exact time.

Edited by AtomicCEO
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That's what I thought.

 

But I didn't know if the force caused by spinning would affect it's lift/drop. I guess thats stupid because the force is going to be equal on top and bottom.

 

Bonus question, if a bullet is shop perfectly straight up, does it stop before it strikes the ground?

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Bonus question, if a bullet is shop perfectly straight up, does it stop before it strikes the ground?

 

Assuming "constant conditions"... No. It is always in motion up or down. There is a point where the vector changes from "up" to "down", but it does not stop.

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Won't the elevation of the gun from the earth's surface be a determining factor? A perfectly level gun (oh how I hate that term, "gun", because a gun and a rifle are two different things) fired from the height of 5,280 feet above the earth's surface would surely take longer to expend it's forward energy and then fall to the surface than a gun 3 feet above the surface.

Sure but ACEO is asking about a bullet fired from the gun at the exact same instance a bullet is dropped from the same height as the gun, thus the actual height of the gun itself is irrelevant, all other things being equal.

 

Cue discussion on gravity, terminal velocity, acceleration, etc in 3....2.....1

 

:D

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That's what I thought.

 

But I didn't know if the force caused by spinning would affect it's lift/drop. I guess thats stupid because the force is going to be equal on top and bottom.

 

If anything, the spinning would help prevent the bullet from taking wild dives in any direction and stay on a straight path to hit at the exact time.

 

Physics in relatively simple analysis like this one can not account for the types of variations caused by spin, shape, etc. You assume that what is happening is happening in a vacuum, and that the only factor at play is gravity.

 

Assuming we are talking HS level physics, otherwise the question gets a little bit more complicated.

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If the bullet that is dropped is dropped so that it is pointed to the ground, I believe it will fall faster than the bullet that has been shot because of aerodynamics.

Edited by muck
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Alright. I went out and shot my neighbors mule (about 500 yards) and had my granddaughter drop a bullet at the same time. Here's what happened. The loudness scared her so bad she wet her pants and forgot to drop the bullet. The mule dropped like a rock but continued to kick in nervous contractions for about 5 minutes. My son said "Dad, that was the wrong mule." We are now digging a hole to bury the dead mule before anyone notices he is missing. My son asked what the hell was this all about. Thanks. Another Huddle experiment gone wrong. Reminds me of the brake fluid/smoke bomb thing awhile back.

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Won't the elevation of the gun from the earth's surface be a determining factor? A perfectly level gun (oh how I hate that term, "gun", because a gun and a rifle are two different things) fired from the height of 5,280 feet above the earth's surface would surely take longer to expend it's forward energy and then fall to the surface than a gun 3 feet above the surface.

 

This is my rifle.

This is my gun.

This is for fighting.

This is for fun.

Edited by MojoMan
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Seriously...are you trying to answer a physics question in the "High School Physics Homework" sense, or are you looking for a real world answer?

 

if it's in the "high school physics" sense, ignoring all other variables (terrain, wind resistance, curvature of the earth, etc), they hit at the same time.

 

acceleration = velocity/time

velocity = distance/time

 

therefore, acceleration = distance/[time * time] --> time = square root of [distance / acceleration]

 

we know acceleration (gravity) and we know the distance (the height of each bullet, which is the same). therefore, the time is the same.

 

:D

 

atomic, please copy this in your own handwriting. i don't want to get in trouble with your teacher.

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if it's in the "high school physics" sense, ignoring all other variables (terrain, wind resistance, curvature of the earth, etc), they hit at the same time.

 

acceleration = velocity/time

velocity = distance/time

 

therefore, acceleration = distance/[time * time] --> time = square root of [distance / acceleration]

 

we know acceleration (gravity) and we know the distance (the height of each bullet, which is the same). therefore, the time is the same.

 

:D

 

atomic, please copy this in your own handwriting. i don't want to get in trouble with your teacher.

 

I always copy physics off the Asian kids.

 

Sorry, Caveman Mick... unless you're Matt Damon from Good Will Hunting, I'm putting my money on Montster here.

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I always copy physics off the Asian kids.

 

Sorry, Caveman Mick... unless you're Matt Damon from Good Will Hunting, I'm putting my money on Montster here.

 

 

Heck, I'd put my money on Montster as well. His HS Physics answer is much easier to understand than any aerodynamics answer I would give based on a college course I never took.

 

How do ya like dem apples?

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Heck, I'd put my money on Montster as well. His HS Physics answer is much easier to understand than any aerodynamics answer I would give based on a college course I never took.

 

Three times in this thread, you've called it "high school physics", and yet you've never given a hint about what other factors are at play.

 

Drop your knowledge, or stop trying to give everyone blue balls.

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Three times in this thread, you've called it "high school physics", and yet you've never given a hint about what other factors are at play.

 

Drop your knowledge, or stop trying to give everyone blue balls.

 

being asian, i've already climaxed from this thread. no blue balls here.

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