what will happen without inertia

[aman0076]

what will happen if there if no inertia on earth.
Everyone is requested to give answaer
I am waiting for answer :whiste:

 

[ElenaP]

Lots of fun.

No brakes in cars, except for parking. All stopping is by wind resistance as soon as engine stops. Cannot remove the parking brake because cars will get blown around by the wind.

No internal combustion engine because flyweels do not work. Probably no jet as well? Looks like electric power only. That's also a problem because turbines do not work. So electrical generation is like thermocouples and solar only, fairly limited.

 

[ElenaP]

On the more global scale, no Earth rotation, climate change, and so on.

 

[DrPizza]

Inertia = mass. There wouldn't be an Earth. Without mass, there wouldn't be anything holding the Earth together. Without mass, the Earth wouldn't stay in orbit around the sun. The Earth would simply float apart.

edit: on 2nd thought, I don't think the Earth would fall apart.

 

[CLite]

If the earth was rotating at it's current speed when mass was suddenly removed it would fling itself apart.

The reason is that every particle along a radial path from the earth's center has a velocity that is tangent to that path. What keeps them in a circle is a constant acceleration back down the radial path causing the velocity to change in direction constantly as the earth spins. The source of this acceleration is gravity from the earth's mass. Without it the particles would just travel in the tangent direction and hence the earth would be ripped apart.

 

[Farmer]

This question is ridiculous.

If there were no massive particles, all particles would be massless. Under current physical understanding, that means all particles would travel at the speed of light and be governed by a quantum field theory.

Nothing would be the same, its almost unimaginable.

I wish you would post this on OT so I can parody it.

 

[ElenaP]

The inertia is not the same as mass or gravity.
Mass is the property of an object.
Inertia is the ability of the object to keep moving (at whatever speed, possibly zero).
Gravity is the ability of two objects to attract each other.

If you drop an object and there is no inertia, the obejct immediately accelerates to its terminal speed, falls to the ground, and sticks to the ground (without breaking).

As a bonus, you do not need to walk downstairs when there is no inertia, just jump via the nearest window.

 

[Turtle.Man]

Inertia is very definitely equal to mass: I recall having to prove this during a physics exam. I = M.

 

[Farmer]

The inertia is not the same as mass or gravity.
Mass is the property of an object.
Inertia is the ability of the object to keep moving (at whatever speed, possibly zero).
Gravity is the ability of two objects to attract each other.

If you drop an object and there is no inertia, the obejct immediately accelerates to its terminal speed, falls to the ground, and sticks to the ground (without breaking).

As a bonus, you do not need to walk downstairs when there is no inertia, just jump via the nearest window.

In the currently formulation, mass is a quantitative measure of inertia. I can cite Newton's 2nd Law but I think you would perceive that as insulting. With only only subtle differences, mass is also the "charge" for gravitational force. You can't speak of the 3 separately.

In other words, you are attempting to apply F = ma to objects that are massless. Outside a few idealizations taken in the classroom (like massless springs), you can't apply that to massless objects, it is beyond the scope of Newtonian mechanics.

Relativity can handle massless objects, the most famous one being the photon. If you are going to speak about how massless object interacts and exchanges energy with fields, you will have to use the language of quantum field theory.

 

[CLite]

@ElenaP,

Inertia is not a fundamental property, there is no "inertia" to measure, it is an aberration of F=ma which is the fundamental property. A force is applied to an object and it accelerates based on that force and mass. So to say there is no inertia would mean objects are massless. There is no measurable value of inertia you can claim is 0, since inertia is a concept and not a property.

 

[wuliheron]

what will happen if there if no inertia on earth.
Everyone is requested to give answaer
I am waiting for answer :whiste:

If there were no inertia on earth you'd stop waiting for answers.

 

[ElenaP]

I'm trying to answer his question, which is probably incorrect but still fun.
You are trying to explain why the question is incorrect, which is probably correct but nonetheless boring.

By the way, F = ma and F = k*m1*m2/r^2 are different things. If you are allowed to change the world at will, like in original question, you can change the world so there be F = a*0 and F = k*m1*m2/r^2 at the same time, no problem.

The original question is not about physical correctness, it is about fun. Silimar to "what the chemistry would look like if electons had no spin?".

 

[CLite]

I'm trying to answer his question, which is probably incorrect but still fun.
You are trying to explain why the question is incorrect, which is probably correct but nonetheless boring.

By the way, F = ma and F = k*m1*m2/r^2 are different things. If you are allowed to change the world at will, like in original question, you can change the world so there be F = a*0 and F = k*m1*m2/r^2 at the same time, no problem.

I didn't say why the question was incorrect, I originally offered a point of view that everything would rip apart. Then you said inertia is not the same as mass, so that's why I discussed how inertia doesn't mean anything, it's just an artificial concept.

Anyways in your proposed world everything would still be ripped apart because the slightest forces, including gravity, strong/weak nuclear force, electromagnetic would cause objects to move at light speed (infinite acceleration).

 

[wuliheron]

Nobody knows how inertia is created so nobody knows exactly what impact it might have if it were to suddenly disappear. You might as well ask what would happen if Indeterminacy were to disappear. There is no clear causal relationship other then the obvious making the whole question along the lines of how many angels can dance on the head of a pin.

 

[QuantumPion]

Inertia is very definitely equal to mass: I recall having to prove this during a physics exam. I = M.

Intertia is NOT mass. Intertia is the resistance to acceleration under an applied force. You are confusing intertial mass with inertia itself.

The inertial mass of an object is equal to mi = F / a.

The gravitational mass of an object is equal to mg = G*m1*m2 / r^2

All experiments to date have shown that gravitational mass = inertial mass, this is called the equivalence principle.

 

[CycloWizard]

If the earth was rotating at it's current speed when mass was suddenly removed it would fling itself apart.

The reason is that every particle along a radial path from the earth's center has a velocity that is tangent to that path. What keeps them in a circle is a constant acceleration back down the radial path causing the velocity to change in direction constantly as the earth spins. The source of this acceleration is gravity from the earth's mass. Without it the particles would just travel in the tangent direction and hence the earth would be ripped apart.

This isn't necessarily the case. The earth is also held together by the elasticity of its constitutive materials. Indeed, the problem for elastic stresses arising in a rotating spheroid constructed from accreted layers (i.e. a planet) has been solved in the literature both with and without gravitational effects.

 

[DrPizza]

Intertia is NOT mass. Intertia is the resistance to acceleration under an applied force. You are confusing intertial mass with inertia itself.

The inertial mass of an object is equal to mi = F / a.

The gravitational mass of an object is equal to mg = G*m1*m2 / r^2

All experiments to date have shown that gravitational mass = inertial mass, this is called the equivalence principle.

Gmm/r² is a force, not a mass. It's the gravitational weight of an object.

Inertia and mass are pretty much the same thing - the only thing that's different is the way each of those terms is defined, and thus how each is determined. Yet both definitions still arrive at the same "thing."


Also, regarding things flying apart due to a lack of gravity - what I started thinking more about was the fact that things like rocks, etc. - most of the earth - is held together with chemical bonds. Even weak van der waals forces are stronger than gravitational forces. Gravity is a pathetically weak force. Thus, it seems (at least to me) that all else being equal - just no more mass (or inertia), the Earth would stay together. Of course, without gravity, fusion is going to cease to exist in the sun & bad things are going to happen there.

 

[wuliheron]

Forget the other forces for the moment, inertia is what compels objects to move in a straight line, to keep moving unless acted upon by an outside force, etc. Take that away and there is no compelling explanation for why something should or shouldn't move. Would the earth disappear from the universe? Stop dead in its tracks? Keep rotating and revolving around the sun? There is absolutely no mechanism left whatsoever to explain what would happen and anyone's guess is as good anyone else's.

For example, there is the theory of negative mass. Something made of negative mass would obey Newton's laws of motion except for every action there would be an equal reaction. Not an equal but opposite reaction, just a reaction. Hit a ball with negative mass with a bat and it will fly into the bat with the same amount of energy you hit it with. Its a fun theory to play with, but the important thing is the theory provides a framework in which to predict how things move. Without any such framework you might as well spend your time guessing how many angels can dance on the head of a pin. In this case, we were asked what would happen if inertia disappeared. Not just rest mass, but inertia. Without any inertia whatsoever there is no guessing what would happen.

 

[aman0076]

thanks friends for all your answers
And sry for this type of silly question

 

[silverpig]

My answer to this question would have been the same as Farmer's answer. No inertia means that everything is equivalently massless. This means everything would be moving at the speed of light, everything would be made of energy (not mass) and to you (assuming a pure energy version of you was possible), the entire age of the universe would pass by in an instant.

Inertia is the resistance of an object to changes in velocity. The more massive the object, the more difficult it is to change its velocity. If something has no inertia, that means it does not resist changes in velocity at all. If you started off with a particle at rest, as soon as it interacted with something, it would be moving at the speed of light and you'd get the result Farmer described above.

 

[Borkil]

you would get CARMAGEDDON!

 

[Turtle.Man]

Intertia is NOT mass. Intertia is the resistance to acceleration under an applied force. You are confusing intertial mass with inertia itself.

The inertial mass of an object is equal to mi = F / a.

The gravitational mass of an object is equal to mg = G*m1*m2 / r^2

All experiments to date have shown that gravitational mass = inertial mass, this is called the equivalence principle.

That's exactly what I had to prove on the exam: the details were dim after 30 years.