It's Physics Time!

[Billy.]

If you fire a gun which is set up to fire at precisely 90 degrees (horizontal to the ground) and drop a bullet at the exact time at which the bullet exits the muzzle, both bullets will touch the ground at the same time, so long as the distance between the gun and ground remains constant. :blink:

 

Good old physics fact, put to test by the Mythbusters

 

Edited June 21, 2010 by Billy.

[welsh warrior]

i love myth busters watch them all the time this is an old one ....

[Vipa]

That was amazing..... Physics & maths were/are my strong points but I can't for the life of me get my head round this one! :blink:

[Dekers]

That was amazing..... Physics & maths were/are my strong points but I can't for the life of me get my head round this one!

 

 

Horizontal speed is irrelivent, if it goes faster it will just travel further before it hits the ground, gravity has the same effect on both!

 

The reality is of course it can only be true when air pressure etc is equal and the ground is level (NOT CURVED like the earth). :blink:

[Billy.]

That was amazing..... Physics & maths were/are my strong points but I can't for the life of me get my head round this one!

 

 

As has already been said. The main fact is that the gun is exactly level, meaning the bullet is not being fired against gravity. The force of gravity is the same, if you're travelling at 0 mph or 700.

[djrwood]

Definately true but is still quite hard to get your head round. I suppose as long as the mass of both bullet heads are identical this would be true. Although you would think that the frictional forces on the fired bullet would have some effect I guess they don't as gravity is the only force which is pulling the bullets down to earth.

 

I wonder what would the results be if the trajectory of the fired bullet is altered, and the other bullet is dropped from an equal height of the peak of the fired bullet? Therefore the dropped bullet would get to the ground first as it would be falling while the fired bullet gains height!? Does this make sense as I've confused myself

 

Dan

[Vince Green]

The other thing that is amazing is just how quickly a pistol bullet hits the ground if its fired dead level. It only goes about 220 yds

Years ago we were at a reservoir in North Wales, it was dawn and the water was like a mill pond. We were firing a 9mm pistol out across the water. You could see the bullets hitting the water a few hundred yards out. Even elevating the pistol right up didn't send them a whole lot further, maybe 4-500yds tops.

Edited June 22, 2010 by Vince Green

[HW682]

To make it really interesting they could do it in a very large vacuum chamber and watch a dropped feather hit the floor at the same time as the fired pistol bullet :yp:

Edited June 22, 2010 by HW682

[vampire]

Horizontal speed is irrelivent, if it goes faster it will just travel further before it hits the ground, gravity has the same effect on both!

 

The reality is of course it can only be true when air pressure etc is equal and the ground is level (NOT CURVED like the earth).

I was always and still am **** at physic/maths,but surely the earth being curved and the bullet trajectory being curved equal each other out :yp:

[welsh warrior]

To make it really interesting they could do it in a very large vacuum chamber and watch a dropped feather hit the floor at the same time as the fired pistol bullet :yp:

 

good idea

[HW682]

I was always and still am **** at physic/maths,but surely the earth being curved and the bullet trajectory being curved equal each other out :yp:

 

At a certain height and speed that would be true - it is called going into orbit. In effect the object is constantly falling to earth but "missing" it over the horizon.

[rodp]

Just going off thread slightly (sorry) has anyone ever tried a dimpled bullet / pellet as in golf balls. It's supposed to make them fly more accurately and substantially further for a given force (I believe)

 

:yp: .

[rodp]

At a certain height and speed that would be true - it is called going into orbit. In effect the object is constantly falling to earth but "missing" it over the horizon.

 

 

Height wouldn't matter I don't think but it wouldn't half have to be shifting :yp:

[HW682]

>>Newtons cannonball on wiki<<

this link shows it in a simple diagram.

 

Animated versions... >>click1<< or >>click2<<

 

 

The required speed to go into orbit varies with height. For a typical bullet speed the orbit height would be somewhere in the order of 500,000 miles above earth.

Edited June 22, 2010 by HW682

[Dekers]

I was always and still am **** at physic/maths,but surely the earth being curved and the bullet trajectory being curved equal each other out :yp:

 

The bullet trajectory is curved because of gravity..END OF!

 

The curvature of the Earth comes into play as the "floor" will fall away and therefore be lower if you travel a distance compared to simply dropping a weight. Therefore if the bullet is very fast and travels a long way the floor actually gets further away so the reality will not work.

 

It will only work if the floor stays totally flat until the fired bullet hits the ground!

 

Yes, I can see it takes a minute to grasp, But it does work.

 

In simple terms an equal playing field and gravity does the rest!

 

ATB!!

Edited June 22, 2010 by Dekers

[Vipa]

>>Newtons cannonball on wiki<<

this link shows it in a simple diagram.

 

Animated versions... >>click1<< or >>click2<<

 

 

The required speed to go into orbit varies with height. For a typical bullet speed the orbit height would be somewhere in the order of 500,000 miles above earth.

 

hmmm.... that would be one hell of an orbit as the moon is only 283,000 miles above the earth!!! :blink:

[casts_by_fly]

>>Newtons cannonball on wiki<<

this link shows it in a simple diagram.

 

Animated versions... >>click1<< or >>click2<<

 

 

The required speed to go into orbit varies with height. For a typical bullet speed the orbit height would be somewhere in the order of 500,000 miles above earth.

 

 

HW,

 

Where did you get the 500k number from? The way I see it, the bullet and the moon should have similar orbital paths because they have similar linear speeds. The moon is roughly 3300 fps and many bullets are in that same range as well.

 

Thanks

Rick