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# What Happens When an Unstoppable Force Meets an Immovable Object?

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1. (Original post by Hype en Ecosse)
Physics doesn't work like that. Just because something has no mass does not mean it has no energy. Take a photon, for example. Life is pretty ****ed if a photon doesn't carry any energy. E = mc^2 is only intended to describe the energy of objects with mass, it does not apply when m = 0.

Forces are indirect quantities. It's not massive, nor does it exist in any sort of wave state - it is simply a thing which causes an object to change in some way. The causes of a force are the complicated bit! So no, forces don't have mass!
Haha, yes. People often don't know E=mc squared is a version with momentum removed.

The full version:

Contains a reference to momentum.

An "immovable object", which cannot exist, would have a momentum of zero though! And thus this part of the equation would fall out - but a mass 0 momentum 0 object simply would cease to exist.
2. bugger all.
3. Gotham is threatened by bombs?
4. Breakthrough
5. It's a hypothetical scenario without an answer. There can't exist two entities which logically conflict with one another - an unstoppable force can't be stopped, yet an immovable object is capable of stopping any force - these two concepts can't both exist and yet remain logically congruent. The paradox comes about because the situation where an unstoppable force meets an immovable object is undefined as it represents a contradiction in terms.
6. (Original post by Hanvyj)
...
An immovable object would be an object that is immovable relative to another surface, it is better to think of it this way. Then, there is energy stored within the system (an infinite amount) as there are some attractive forces, be they electrostatic, gravitational or nuclear.

If the surface on which the object is placed is not immovable however, then the unstoppable force will cause the surface to move. Thus, the immovable object is not being moved, relative to its surface, and the unstoppable force is not being stoped - this is basically what Stratos said on the first page.

If however, the surface on which the immovable object is placed or some way attracted to, is immovable relative to its surface and each subsequent surface is immovable to its surface ad infinitum - then you have a problem
7. (Original post by DylanLJG)
So what do people think happens when an Unstoppable Force meets an Immovable Object? Interesting Paradox, anyone got any ideas?
The force moves through the object. Simple as.
8. (Original post by yomomalomo)
An immovable object would be an object that is immovable relative to another surface, it is better to think of it this way. Then, there is energy stored within the system (an infinite amount) as there are some attractive forces, be they electrostatic, gravitational or nuclear.

If the surface on which the object is placed is not immovable however, then the unstoppable force will cause the surface to move. Thus, the immovable object is not being moved, relative to its surface, and the unstoppable force is not being stoped - this is basically what Stratos said on the first page.

If however, the surface on which the immovable object is placed or some way attracted to, is immovable relative to its surface and each subsequent surface is immovable to its surface ad infinitum - then you have a problem
The question mentions nothing about surfaces. We have to assume a certain reference plane however, it is natural and logical to assume "stationary" is the frame of reference where the object is not moving with any velocity. Saying "Stationary" is a frame of reference defined by the position of another object or surface not even mentioned in the question is silly, and I don't see how its better to think of it that way.

Given the most natural and logical of reference frames being the "immovable" object's position as "stationary" then your answer doesn't make sense.

Look, here is a nice paint diagram showing the fallacy of that answer:
9. The impossibility of the situation means that it will produce an impossible outcome.
10. (Original post by Hanvyj)
...
If we are to try and reify this hypothetical question to some degree, so as to delve into it further, then we must know that an object is not immovable by sheer fact that it is immovable - this is nonsensical and not real. It is immovable because it is attracted to (or repelled from) some other matter, with the attraction or repulsion being infinitely strong.

Your picture is incorrect because in both versions, the immovable object is moving relative to a surface (we'll call it a surface for the sake of simplicity, it could be any type of matter of any size and density that has mass or electric charge or is made up of quarks, in fact space itself could count as a surface). The start position is actually the surface. So what I was saying is that if the surface is not itself held in place (by either the rest of itself or other external surfaces) by an infinitely strong force, then the surface will move i.e. the start position itself moves. The immovable object is still not moved, because it is impossible to move it from the surface it is attracted to (i.e it has not moved relative to that starting point) or move it to the surface it is repelled from, while the unstoppable force is not stopped or reduced because it continue to do work at the same rate (infinity).

The problem does however arise if we have an immovable object which is attracted to a surface which is itself immovable - this is probably what I would call a true immovable object.

Doing the maths, we either have the immovable object still immovable but the unstoppable force stopped - resultant force = 0
or
we have the unstoppable force stopped and the immovable object moving in a positive direction with infinite velocity - resultant force = infinity
or
we have the unstoppable force continue forward, not stopped (some how through the immovable oject ) while the immovable object moves in the negative direction with infinite velocity (it has infinite negative momentum) - resultant force = negative infinity.

So that is not really a satisfying answer either.

But then the above is not true either. Because if the force is going to continue being unstoppable i.e continue to be applied, then how can it be applied to a system in which each particle is immovable relative to the other? It just becomes more and more crazy - is there then no energy in the system because the forces of the surrounding particles cancel each other out? Can either of the things actually exist at all, whether alone or together? I don't know but what I will do is say "fudge this question I'm going to sleep"!

PS. I'm sorry if most of it makes no sense at all - I'm tired and part crazy
11. ROYP is born
12. The unstoppable force would go around the immovable object, that way the immovable force doesn't move and the unstoppable force...doesn't stop
13. Nothing happens the unstoppable force will forever be moving, and the immovable object will forever be stopping it.
14. (Original post by yomomalomo)
If we are to try and reify this hypothetical question to some degree, so as to delve into it further, then we must know that an object is not immovable by sheer fact that it is immovable - this is nonsensical and not real. It is immovable because it is attracted to (or repelled from) some other matter, with the attraction or repulsion being infinitely strong.
An imovable object is imovable by its very definition - its in the name. Of course its nonsensical and not real, that was my point - the question is wrong.

However, you then start introducing this random other object that is is "attracted to" with an (equaly imposible) attractive force for no reason whatsoever other than the fact that "It is immovable because it is attracted to (or repelled from) some other matter". Which I can't see any basis for - the object in the situation is described as immovable. As far as I can see, we can only assume two things from this:

1) The object is not moving. This means we have a "stationary" reference frame, the initial frame of reference of te object at which it is at rest (velocity of 0).

2) The object cannot accelerate.

Where do you get the "must be infinatley attracted to some other random matter" from? What is the basis of this?

(Original post by yomomalomo)
Your picture is incorrect because in both versions, the immovable object is moving relative to a surface (we'll call it a surface for the sake of simplicity, it could be any type of matter of any size and density that has mass or electric charge or is made up of quarks, in fact space itself could count as a surface). The start position is actually the surface. So what I was saying is that if the surface is not itself held in place (by either the rest of itself or other external surfaces) by an infinitely strong force, then the surface will move i.e. the start position itself moves. The immovable object is still not moved, because it is impossible to move it from the surface it is attracted to (i.e it has not moved relative to that starting point) or move it to the surface it is repelled from, while the unstoppable force is not stopped or reduced because it continue to do work at the same rate (infinity).
The diagram is correct. The observational frame of reference (the "drawing") is one which does not accelerate, a natural position for measuring the immovability of objects...

My point was that in both cases the object is moving. Your "surface" which moves in the diagram is the cat. Stop calling frames of references surfaces! But the even though your random reference frame attatched to the object moves it still measures an acceleration, because you can't just move the "true" reference frame, we assume that has a velocity of 0 and continues that way - thus has no acceleration (which the object is experiencing) so they can't just magically stick together.

F=mA, the object has a mass and a force is exerted on it - it must undergo an acceleration or its components (deform/break) or break the laws of physics.

So we either break the laws of physics or the rules of the question.

(Original post by yomomalomo)
The problem does however arise if we have an immovable object which is attracted to a surface which is itself immovable - this is probably what I would call a true immovable object.
This made me laugh. So you can't have an immovable object (it has to be repelled infinatley from another object duh) but what if that other object is truly immovable! O_O

Didn't you just rule out something being "truly" immovable by the premis of this other object lol? You turned your own reasoning into circular logic, or just destroyed the need for it at all...

(Original post by yomomalomo)
Doing the maths, we either have the immovable object still immovable but the unstoppable force stopped - resultant force = 0
The object must have moved when any force is applied. F=ma. Lets do the math... any force and any mass results in finite acceleration.
(Original post by yomomalomo)
we have the unstoppable force stopped and the immovable object moving in a positive direction with infinite velocity - resultant force = infinity
infinate velocity???? really?? Isn't that, well, kind of moving?
(Original post by yomomalomo)
we have the unstoppable force continue forward, not stopped (some how through the immovable oject ) while the immovable object moves in the negative direction with infinite velocity (it has infinite negative momentum) - resultant force = negative infinity.

So that is not really a satisfying answer either.
I'm glad you came to that last conclusion - the question is flawed, hense there is no satisfactory answer.

(Original post by yomomalomo)
But then the above is not true either. Because if the force is going to continue being unstoppable i.e continue to be applied, then how can it be applied to a system in which each particle is immovable relative to the other? It just becomes more and more crazy - is there then no energy in the system because the forces of the surrounding particles cancel each other out? Can either of the things actually exist at all, whether alone or together? I don't know but what I will do is say "fudge this question I'm going to sleep"!

PS. I'm sorry if most of it makes no sense at all - I'm tired and part crazy
Well, we generally came up with the same conclusion - the question is utterly flawed.

To put it simply, an "object" cannot be immovable when a force is applied unless it doesn't conform to newtons second law - ie isn't matter - ie isn't really what I would consider an "object"...
15. You are trying to place not one, but two infinite concepts into a finite context.
16. The unstoppable forces goes into the immovable object. Since it's immovable it must have infinite mass. Since it has infinite mass, it must be boundless...

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