You can also get a higher bounce withball stacking, but you would have to be really careful with your alignment.
It surprised all of us why it went high, we didn’t expect a high bounce. It probably wasn’t as high as my memory remembers it anyway.
I always wondered where that bowling ball came from. Thanks!
Is this still “The Straight Dope”? Twenty-two replies in this thread and no one has pointed out this glaring fallacy?
It’s true that a rock will fall faster than a feather in an atmosphere, but that is due to air resistance, not density. Vacuum or not, density has no bearing on terminal velocity if the two objects have the same aerodynamic drag. A solid cannonball will fall at the same rate as a hollow cannonball. Mass has no effect – any object in freefall acted on only by gravity will fall with an acceleration of 9.8m / s2.
My ex-gf’s checks used to bounce so high that the store detectives could never get their hands on them and she was never busted for paper hanging.
She had a real good run until she tried to buy a motorcycle from a cop on Craigslist and he called all his friends and they all showed up one night and threw a net over her.
Still, it was a great motorcycle and when she gets out, I will be sure to thank her for it.
Thankfully, I had enough presence of mind to move it out of the country as soon as she bought it and so they could never find it. But she still got seven years because it was her third strike and she had previously gotten all kinds of warnings.
But, aside from that one flaw, she was a wonderful woman. I just wish I could have kept her on the outside.
The Bouncing Bomb.
Is that the same as The Bouncing Betty?
Which didn’t actually bounce very high.
Fortunately, since the whole point of the bomb was to bounce a few times, then sink into the water behind the dam.
The “Bouncing Betty” was the Allied name for the non-aircraft-launched German “S-bomb”
I swear I’ve seen videos or toys that use that same principle to bounce the top ball super high. If we make a couple of those out of that LiquidMetal stuff, we might be on to something.
Re: the OP, do bouncing photons count?
What about the pull of the object on Earth? Does that matter?
Just to be explicit: the bouncing bomb was a dam-destroying bomb dropped from an airplane. The Bouncing Betty is an anti-personnel land mine that pops up and then explodes in midair, used against troops. It doesn’t really bounce, but I guess “Leapin’ Lonny” just doesn’t have the same ring.
1 - The previously mentioned moon
2 - A He (or H2), balloon thrown to impact the ground before rising.
3 - a spacecraft ‘skipping’ (bouncing) off the atmosphere
But I think the winner are those little photons bouncing off a mirror (again already mentioned)
I move that this thread be moved to MPSIMS since at best there have been only a couple of serious responses to the OP. 
I was reading the posts and going to say the same thing. Here’s an experiment, put a feather on top of a book and drop them both. The feather will stay on top of the book and fall at the same rate because it’s protected from air resistance.
But would the two cannonballs have the same aerodynamic drag as you suggest? The wikipedia entry on terminal velocity says this:
and this specifically about spherical objects:
Doesn’t that mean then that two cannonballs with the same projected area but different masses would fall through air at different rates?
Am I missing something?
Yes. For a simple example, a ping-pong ball will fall slower than a golf ball. But for metal balls like cannonballs, and reasonably-achievable drop heights, the air resistance of any of them is going to be small enough that you might as well neglect it.
If you drop two cannonballs, one of copper and one of uranium, out of an airplane, will they hit the ground at PRECISELY the same moment, or will they get going fast enough that their terminal velocity, which is definitely affected by their density and mass, comes into play?
To be clear, unless I’m just massively confused here, the speed at which objects fall in an atmosphere IS dependent on their density, which is why a ping pong ball falls slower than a golf ball which falls slower than a golf-ball-sized sphere of depleted uranium. I’m happy to believe that the difference in falling speed between, say, a sphere of iron and a sphere of gold, is very very very small, but nearly identical and identical are not the same.
(In a true vaccuum, of course, objects all DO fall at the same speed, perhaps barring crazy fringe situations.)
My bolding
If you are going to bitch about the quality of answers, can I suggest that you at least provide accurate ones yourself?
This is the equation for terminal velocity.
V_t= sqrt( (2mg) / (rho A C_d )
where
V_t is terminal velocity,
m is the mass of the falling object,
g is the acceleration due to gravity,
C_d is the drag coefficient,
rho is the density of the fluid through which the object is falling, and
A is the projected area of the object.
Two spheres of unequal densities but identical dimensions will have different terminal velocities. The drag coeffiecient and projected area of the spheres will be the same, so the terminal velocity will change as a factor of the square root of the difference in masses.
If you are talking about dropping the ball off the table, then yes, you are correct.
No, you are right.
A 747 will fly at over 10,000 meters. With no air resistance, a dropped object would be traveling at 442.72 m/s or 1593.79 km/h.
Theterminal velocity for a 10 cm iron ball is 178.6 m/s where it would be 279.6 m/s for a similar ball made of gold. This is not trivial.
Without air resistance, a ball would fall from a plane in about 45 seconds.
Neglecting the effect of air resistance on how long it takes the balls to reach their respective terminal velocities, my calculation give that the gold ball will fall in about 50 seconds while the iron one would take around 65 seconds.
Bernie Madoff kited and bounced checks with so much verve that the recoil bounced him all the way from Manhattan to North Carolina.
This points to an important problem, namely the limited tensile strength of the materials involved. A good bounce requires elastic deformation of the projectile and/or the bouncing surface, meaning that the two objects return to their original shape after the collision, with most of their kinetic energy maintained in forward motion (very little going to vibration or heat). When you start talking about massive objects and/or high speeds, we end up with plastic deformation: the objects do not return to their original shape, and that permanent deformation dissipates some energy as heat. In the worst case, the materials fracture.
Good example here (fast forward to ~1:50), in which a 50-pound ball of Sillly Putty is dropped from a tall building. A small ball of SP would bounce just fine, even from this great height, but the giant ball of SP shatters upon impact.
I think everyone is talking about the same thing, but in a different way. Without air resistance, everything falls at the same rate regardless of its mass. Drop a hollow cannonball and a regular cannonball off a regular building and they’ll hit at the same time.
However, if dropped from hundreds of feet altitude, they will reach terminal velocity, and heavier objects do have a higher terminal velocity so the regular cannonball hits first.
Gravity still acts the same on both and they both fall at the same rate, it’s just that the heavier one will accelerate longer than the lighter one because it takes more air resistance to slow and stop its acceleration.
Is that correct? It seems to be in disagreement with this:
where they give an equation that is a function of mass.
From here: Drag (physics) - Wikipedia
That seems to suggest that the heavier cannonball will have a slightly higher acceleration as well as a higher terminal velocity.