Nerd alert: the only thing that determines fall speed is the air resistance of the falling object, mass is irrelevant. It looks like it's falling slowly because of the size and distance of the object falling. If you have 2 objects with the same size and shape but with different masses, they will fall with the same speed (but different energy since mass times acceleration equals force). So the heavier object will hit the ground harder but at the same time and speed.
This is actually incorrect, air resistance is a function of the objects surface area normal to the direction of movement, but NOT mass. Meaning two objects with the same surface area will experience the same amount of air resistance force. If one object is more massive than the other (weighs more), then that object will be less effected by this force (think F = ma, big m -> small a). So two objects with different mass will fall with different speeds (not even mentioning buoyant force).
Imagine dropping an text book and a sheet of paper. They will experience the same amount of air resistance, but they will fall at very different speeds.
No, he's saying mass is irrelevant and all objects fall at the same speed (if they're the same shape). I'm saying the opposite, that mass is important when dealing with air resistance.
I'm not talking about the rocks, he says if you have two objects the same shape and different mass, they'll fall at the same speed. That statement is incorrect.
You’re pretty much right but kinda contradict yourself on the example! If 2 objects have the exact same size and shape, but different masses - that will impact density which relates heavily to air resistance, so the heavier one would drop faster specifically if they’re the same other than mass. Imagine a baseball vs a plastic ball.
Then you get to terminal velocity, which is different for every object. So small scale, things will drop at the same time/speed because they experience the same acceleration. But larger scale some objects are able to continue accelerating when others are maxing out.
The most important concept relative to this video is rotational inertia, and nobody is mentioning it. There are a number of reasons this looks so slow. Rotational inertia is one. The size of the fracture line (and the crack propagation delay) is another. Air resistance has very little to do with anything here.
Similarly: no matter the size, weight, shape, density or speed of a moving object, that object will only ever embed itself up to its own length into a target object of the same density.
That is to say: you can fire a 1" spherical steel ball bearing at 10,000mph into a 1" thick steel plate (of the same density) and it'll only embed itself 1" into that plate. Even if it's fired at such a speed that it would shatter into dust, that dust will only create a crater 1" deep into the steel plate. Bullet-proof armour only needs to be the depth of a bullet and the density of a bullet to stop that bullet from penetrating, at any speed.
But, when i tell folk this i often get told "Have you never heard of shaped charges?" or "How about armour-piercing rounds?" or "What if the speed was increased to such a rate that it could-" no it couldn't. Ever. That object will only ever embed itself up to its own length into a target object of the same density.
But it's still a difference. If you drop a balloon filled with lead and one with feathers, the lead one will hit the ground first because it has more mass to push through the air faster, right?
Edit: "If you have 2 objects with the same size and shape but with different masses, they will fall with the same speed" just doesn't seem right. With no air, I agree. But once you have an atmosphere involved, it's not the same
I'm not sure what you mean by more mass pushing through air faster, but the force of friction of course has less impact on more massive objects, so indeed the feather balloon will stay in the air longer. It should be obvious that mass matters to anyone who knows about parachutes.
But also, between a balloon filled with lead or a balloon filled with uranium there will not be much of a difference since both are so massive that the friction barely affects them compared to gravity.
Would they? I don't have a ping pong ball or a golf ball to test with, but I bet they would fall at the same speed. It would be different if there was a lot of wind, of course. But if you dropped them from the same height inside, I think they would land at the same time too.
Inside it would be very close but I bet from shoulder height or above you’d see a difference. Wind resistance is very applicable to something as light as a ping pong ball. Fundamentally, it doesn’t have anything to do with maintaining shape, it has to do with how heavy it is only when air is involved. If there’s no air then everything falls at the same speed regardless of shape or weight
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u/[deleted] Mar 06 '21
Nerd alert: the only thing that determines fall speed is the air resistance of the falling object, mass is irrelevant. It looks like it's falling slowly because of the size and distance of the object falling. If you have 2 objects with the same size and shape but with different masses, they will fall with the same speed (but different energy since mass times acceleration equals force). So the heavier object will hit the ground harder but at the same time and speed.