Immovable Object vs. Unstoppable Force – Which Wins?


What happens if an immovable
object meets an unstoppable force? Is a popular question on the internet. Of course, relativity clearly tells us that
there is no such thing as an immovable object – here’s why: If you pick any supposedly immovable
object, or just something like your house or the earth, I can make it move. All I need
to do is start to move relative to it, for example I might ride a rocket, and suddenly
from my perspective, I’m not moving and the earth sails by outside. The laws of physics
make no preference for inertial frame of reference, so from my perspective here, I do not stir,
and yet it’s clear: the immovable object moves! So because of relativity, “immovable objects”
cannot be. But what I think people normally MEAN by “immovable object” is something that
if it’s not moving, you can’t make it start moving by Pushing on it. So, not an immovable
object, but an “un-acceleratable” one. Using Newton’s second law, we know that an object’s acceleration is equal to the total
force on it divided by its mass (though you’ve probably seen this as F=ma). So an “un-acceleratable”
object would be an object with infinite mass; an object so massive that no matter how big
the total force F is, when you divide F by m you always get zero. Of course, as we’ve said, not being able to
accelerate an object doesn’t necessarily mean that the object isn’t moving – it just means
that you can’t directly change its speed – if it’s not moving, then it’ll stay not moving.
And if it’s moving at 100 miles an hour, then it’ll stay moving at 100 miles per hour. So, what about an unstoppable force? Well,
all the fundamental forces in nature are actually caused by particles (like photons or gluons
or gravitons) that interact with an object and change its momentum – the only way to
NOT be affected by a force is to not interact with it at all (like how electrons don’t interact
with gluons so they aren’t subject to the strong nuclear force). Even light itself is
an unstoppable force – every photon that hits your body changes your momentum a tiny little
bit, and there’s nothing you can do about it other than avoid light altogether or become
transparent. So all forces are already unstoppable but my impression is that the phrase “unstoppable
force” isn’t really meant to imply anything about “forces” like electromagnetism or gravity,
but rather, something that you cannot stop from barreling down on you. That is, an object
whose velocity cannot be changed by pushing on it. So, IF by an unstoppable force we mean an
object moving at a speed that can never be changed, then that means the object cannot
accelerate – but wait a second, this sounds familiar! Recalling what we learned earlier,
an unstoppable force must be an un-acceleratable object! And that means that an “unstoppable
force” and an “immovable object” are really just the same, viewed from different reference
frames! Now, since infinite mass requires infinite energy, we don’t know of anything in the universe
that behaves like this, not the least because it would automatically be a black hole so
big that everything in the universe would already be inside of it. But what if we
ignored gravity and imagined there WERE an un-acceleratable object? Well, first it would
be a source of infinite free power and would allow us to live in a 100% happy utopian society
and break the second law of thermodynamics and probably create portals and time travel,
too (you can do a lot with infinite energy). But more importantly, if two of these infinitely
massive un-acceleratable objects were moving towards each other and collided, then since
by definition it’s not possible for the velocity of either of them to change, the only possibility
is that they must pass right through each other with no effect on each other at all.

100 thoughts on “Immovable Object vs. Unstoppable Force – Which Wins?

  1. The unstoppable force vs immovable object is better represented by a shield and a spear
    Where the spear can peirce any shield
    But the shield can block any spear
    Thus what would happen if the spear were to strike the sheild

  2. Unstopable object would go through the immovable object like a ghost and neither will stop or Move.
    You welcome 🤦‍♂️✌😂

  3. serious question, could you make a follow up video for that?
    would it make a giant crunching sound of infinite friction or emit any kind of energy? or would it have to pass through each other in complete silence

  4. I think that all the force would transfer from the unstoppable to the immovable like a newton's cradle, that makes much more sense to me.

  5. Since this conundrum is only a philosophical muse…..there is an easier solution without techno babble. The instant you say immovable object you automatically disenfranchise the term unstoppable force. Likewise if you say it the other way around….unstoppable force vs … well you automatically nullify the meaning of ‘immovable’. It depends on which you say first as setting that parameter by default excludes the other. In reality as the video says….there are no immovable objects in existence…..the whole contemplation is an exercise in resolving a paradox.

  6. I’m going to assume that objects with an infinite mass exist, because more massive objects hold more inertia. If an immovable object is immovable, then it has infinite inertia, which means that it can theoretically push back on a force no matter how much energy is applied to it. If something with an infinite force comes along, the forces cancel out, and the immovable object wins because the net force is 0.

  7. You can only understand true physics in video games! Developers could not not create a spherical map with computers cause the earth is flat!

  8. I’ve heard many physicists talk about gravitons but I don’t think they exist and here’s why. Gravity isn’t a fucking force !!!

    Every physicist is more than familiar with Einstein’s theory of relativity however, no one actually applies it. Relativity is basically fact otherwise GPS wouldn’t work, so why do we treat gravity as a force ? It is merely spacetime curving due to a mass in the field.

    This is probably why physicists have such a hard time quantising gravity. They’re looking for something that doesn’t exist, we search for gravitons to explain why gravity works, like photons etc with the other FORCES of the universe. Why would we need gravitons when the reason gravity works the way it does has already been figured out. And I know it hasn’t been figured out on the quantum scale and many theories may explain this, on those scales gravity might just not be strong enough to influence anything.

  9. The immovable objekt is the crosshair in any fps game, the screen moves and you always see it in the middle of your screen

  10. What happens when we slam nonsense into other nonsense? It's amazing how some of the smartest people in the world can waste their time thinking about the stupidest shit.

  11. The force would stay in front of the immovable object cos if the object can’t move then the force can’t move it so it will stay the same but then the force is unstoppable so it should be able to move the object we could go back and forth for ever but no the force would stop it go around.

  12. they cant go through eachother either… the energy should instead transfer, so, the unstoppable and immovable change status, the unstoppable becomes unmovable
    and vice versa

  13. The way I imagine it is that the unstoppable object's only definition is that it cannot stop, not that it can not be redirected. So an unstoppable object will either bounce back without losing momentum, fly by because it can pass by the object's side relatively easy, or fly sideways because it hits a rather flat surface. Definitions make this question sound stupid. It's not a paradox, if you listen to the words being used, it doesn't even sound like one.

  14. Nobody:

    My brain in the shower : Well if an immovable object exists anywhere then an unstoppable force is just a very hard to stop force, or the immovable object isn’t really an immovable object and it’s moved by the unstoppable force making it not an immovable object but a very hard to move object but if the unstoppable force can’t move the immovable object then the unstoppable force is just a very hard to stop force and the immovable object is still an immovable object ALSOOO-

  15. i mean, theoreticly, the two objects could act as matter and antimatter and destroy eatchother when coliding, seeing as that dosent change their velocity. It mearly destroys the two objects.

    This whould, sadly enough, create an infinitly powerfull explotion. So be sure to stay inside

  16. 3:00 i don't agree.
    If object 1 is infinite mass, and moving with 1 metres per second to object 2, which has infinite mass and isn't moving, then object 1 shouldn't move after colliding and object 2 should move with a 1 metres per second. Because they both have infinite mass, they have the same mass. Which doesn't rely to immovable, but still with infinite

  17. Answer to the last question:
    If A=F/M
    And M=Infinity
    Nothing can stop it, so FORWARD f is infinity
    That would make the sum for them:
    A=Infinity/Infinity
    So they would stop eachother

  18. So if an unstoppable force can't be changed from it's current course, then it is technically immovable. That makes the two the same item and they don't conflict. Maybe.

  19. wat if whgen they meet, a shockwave so powerful emerges, that every atom in the universe is de-composed, or a huge black hole forms destroying everything

  20. Ahm… They WILL pass through each other, but its gonna cause disastrous amounts of energy. Nobody will survive such thing. He forgot to mention that.

  21. Interesting that for an object to be unacceleratable it can have infinite mass or zero mass. So in this situation, light can maybe be classed as both.

    This is my understanding. Might be wrong though

  22. Unstoppable force just goes through the immovable object. The unstoppable force doesn’t stop and the immovable object doesn’t move.

Leave a Reply

Your email address will not be published. Required fields are marked *