Bullet dropped vs. bullet fired

[IBM]

Just made a bet with a mate that the bullet fired will hit the ground after the bullet dropped.

He's certain they'll hit at the same time, and he's not the kind of guy to bet without being certain....and having had a quick look online, it seems he's right. So I'm looking to get out on a technicality.

Within online explanations, it always discounts air resistance, which isn't one of the factors he said should be ignored. So if it's taken into account, should it make any difference to which hits the ground first?

[TeePee]

Curvature of the earth

[mrt9888]

You could make an excuse about stannding on a hill or being a sniper.

[Dareos]

is the bullet being fired straight down? if so i think he is in for a shock...


if its fired straight up however........

[TAKTAK]

if your on a plane and you drop a bullet then it will reach it's terminal velocity slower than a bullet that is fired straight down out of a plane, therefore the fired bullet will hit first if it is fired straight down

[staffsMike]

Surely he pointed out that he was only reffering to a bullet fired parallel to the ground, else any number of things would let you off

If you factor in air resistance and suggest the bullet could generate a certain amount of lift then it would probably not hit the ground at the same time.

[grayg1]

What? O_o

[Dareos]

i think the main problem is finding a perfectly straight vaccuum scenario in which to prove this point

[TeePee]

How would a spinning bullet develop lift? It's a symmetrical airfoil with a 0 angle of attack...

[Lucio]

He's wrong and here's why.

The experiment he's thinking about refers to two bodies of differing weights and size being dropped. They hit the ground at the same time because they are both subjected to an identical force, gravity. The scenario wobbles slightly due to air resistance, as that's an opposing force, which is why it was only proven on the moon in a near vaccuum (there's a video of a hammer and feather being dropped by an astronaut)


Now, in the scenario between a fired gun and a dropped bullet, what happens is that the bullet in the gun is subjected to a *much* greater force than gravity and thus accelerates that much faster, thus reaching it's maximum speed way before the dropped bullet can.

If you want simple visual proof of this, get two identical rubber balls, throw one to the ground and drop the other. The thrown one will hit the ground and bounce up before the dropped one AND will also bounce higher, due to it having more energy. If he still argues point out the fact that you can't see a bullet being fired, but can see one that's dropped

[Agent]

Your friend is forgetting about the insane acceleration the gun bullet will have upon leaving the gun.

[shadowmaster]

There is only one way we can for sure solve this, anyone got a gun?

[Lucio]

There is only one way we can for sure solve this, anyone got a gun?

Nah, it just takes a real man with a pair of balls

[Clunk]

If you were travelling on a giant treadmill that went at the same speed as a bullet and you tried to shoot the pygmy in front of you, would the bullet be instantly halted by the double air resistance and then subsequently kill you to death?

[Lucio]

If you were travelling on a giant treadmill that went at the same speed as a bullet and you tried to shoot the pygmy in front of you, would the bullet be instantly halted by the double air resistance and then subsequently kill you to death?

Nope! because the bullet would still have the same acceleration it had when stationary.

The real puzzler is this: If you were in a car travelling at light speed, and then turned your headlights on, would you still see the beams?

[Clunk]

But it would have the extra wind resistance of the travelling treadmill, so the bullet wouldn't be able to travel as fast?