The law of conservation of momentum is WRONG practically tried.

[dE_logics]

I developed a propulsion system...a propulsion system which has no interactions from the environment...i.e the force in completely internal.

The principle that I used was that when you propel a mass (suppose a ball) on a heavy body and make it hit the heavy body, the impulse that was given to the ball will be transferred to the heavy body. Though the momentum from the ball will be completely transfered, since the body is very heavy, the momentum will be more by virtue of mass...since K.E has an exponential square relationship with velocity, we can say that despite all the momentum getting transferred to the heavy body, most of the energy is still left...this is seen in the form of a recoil on the ball.

Diagrammaticality -

O--------------------------------------------------------------------------------------------------------->|
Ball Propelled and made to collide the heavy body it rests on Wall

Since the the ball is very much lighter than the body, and it possesses the momentum by virtue of velocity, the K.E in it will be much higher...and so we can say that most of the energy will go to the recoil of the ball.

<----------------------------------O |
Ball recoils after hitting the wall

So now...after the collision, since the ball in moving in the opposite direction as before, and if we slowly make it retard (de-accelerate) on the body itself (for e.g using magnets attached on the body and making the ball out of iron), this time, all the K.E that the ball possesses will be given to the body...that means, a much higher velocity attained in the opposite (or desired) direction...and finally for the first time a propulsion without interaction from the surroundings.

Magnet to stop the ball before it collides.
___
<-------------------|___|-----------------------------O
Ball moving in this direction on the heavy bodyIn fact, since the ball is made to propel INSIDE the body, it will initially attain a velocity in the opposite direction, this will also aid the motion in the desired direction (although after collision, the body will again flip velocity).

BUT this is not working ...I mean, I tried it. So the laws are wrong...it's clear. It should have been successful.

Though the conditions were not ideal...I mean, I was using friction to stop the ball (on the body)...but it should have worked!...I was using a ball of a few grams on a ~8KG body on water!

And was throwing the ball by hand.

 

[Doc Al]

I'm having trouble making sense of your post. What exactly did you do and why do you think it violated momentum conservation?

 

[dE_logics]

Is it clear now?

What did you get till now?

 

[Doc Al]

I see that you revised your original post, but it's still not clear. Again: What exactly did you do?

 

[vin300]

For the conservation of momentum, no other force must do work on the interacting entities

 

[dE_logics]

I see that you revised your original post, but it's still not clear. Again: What exactly did you do?

What exactly did you not understand?

 

[Doc Al]

What exactly did you not understand?

Rather than play guessing games, just answer the question: What did you do?

You threw something at something else? What's this about a ball being propelled inside another body?

 

[dE_logics]

For the conservation of momentum, no other force must do work on the interacting entities

Ok...exactly the law is not wrong, but it should have worked!...it's not working!

Any reasons...any flaw with the theory?

 

[dE_logics]

What I think is that the recoil is not sufficient.

The impulse that the ball delivered is more than what is should by the theory and ultimately the recoil is less...

 

[Doc Al]

OK. The best I can determine is that you threw a ball against a wall and it bounced back? So what?

 

[Fenn]

If I'm reading this right, then the reason this won't work is the same reason you can't use fans mounted on a sailboat to create wind for the sails.

 

[dE_logics]

OK. The best I can determine is that you threw a ball against a wall and it bounced back? So what?

That wall was attached to a heavy massive boat...and the ball had iron inside it AND it was lighter by many magnitudes than the boat.

The ball should have recoiled after hitting the wall...its velocity of collision should have almost been equal to the recoil velocity, i.e very less energy would have been transferred to the boat, even though the complete momentum of the ball was delivered to the boat.

What I've done is tried stopping the recoiling ball using a magnet...that way the COMPLETE energy of the ball will be transferred to the boat...i.e without a collision...so boat should have a net propulsion since the energy by the ball has completely been consumed to propel the boat in one direction.

Ok, I'll again try and describe the question.

 

[dE_logics]

If I'm reading this right, then the reason this won't work is the same reason you can't use fans mounted on a sailboat to create wind for the sails.

No you did not read it right.

After the air collides from the sail, it recoils...I'm using this recoil (with almost all its energy conserved...i.e very less goes to the boat...since its heavy).

If you try and stop this recoiling air slowly using the boat itself, all K.E possessed by the air will be consumed to propel the boat in one direction...no doubt there WILL be a propulsion!

Notice there's a difference between collision and stopping something slowly...the later will not have a recoil.

 

[negitron]

No, you've got a net momentum of exactly zero. The reason is that when you throw the ball forward, you give the boat a momentum of -p rearward. When you stop the ball, either with a wall or with a magnet, the force is transmitted back to the boat, imparting a momentum of +p for a net p of 0.

 

[Doc Al]

That wall was attached to a heavy massive boat...and the ball had iron inside it AND it was lighter by many magnitudes than the boat.

You threw a ball against a boat that was against a wall? OK.

The ball should have recoiled after hitting the wall...its velocity of collision should have almost been equal to the recoil velocity, i.e very less energy would have been transferred to the boat, even though the complete momentum of the ball was delivered to the boat.

Why do you think it should have recoiled?

What I've done is tried stopping the recoiling ball using a magnet...that way the COMPLETE energy of the ball will be transferred to the boat...i.e without a collision...so boat should have a net propulsion since the energy by the ball has completely been consumed to propel the boat in one direction.

OK, so you have some mechanism for stopping the ball inside the boat. Assuming that the mechanism is contained within the boat, then I would expect that the energy and momentum of the ball would become part of the "boat+mechanism+ball" system. Certainly no reason to expect momentum not to be conserved. I still don't see why you deduce that momentum is not conserved.

 

[Doc Al]

Or are you on the boat, throwing the ball from the boat against a wall? (Do you see why this is confusing?)

 

[dE_logics]

Why do you think it should have recoiled?

Law of conservation of momentum + law of conservation of kinetic energy thing.If it its a heavy boat and the collision is elastic, it can't happen that it won't recoil.

"boat+mechanism+ball"

That mechanism is a magnet which stops the ball 'slowly' i.e a without a collision. That way, all the energy will transferred to the boat...nothing to the mechanism. If the magnet is a solenoid and its turned off after the ball stops...no energy will be left in this mechanism. All the energy would have been gone to the boat and it would have got propelled in one direction since all the K.E from the ball will be used to do so.

But this is NOT happening practically...so I assume the law of conservation of momentum as wrong.

 

[dE_logics]

Or law of conservation of energy as wrong.

 

[Doc Al]

Law of conservation of momentum + law of conservation of kinetic energy thing.


If it its a heavy boat and the collision is elastic, it can't happen that it won't recoil.

Why do you think the collision is elastic? (And for the nth time, you haven't clearly described, in simple terms, just what you did. Please describe what you did in plain English.)

That mechanism is a magnet which stops the ball 'slowly' i.e a without a collision. That way, all the energy will transferred to the boat...nothing to the mechanism. If the magnet is a solenoid and its turned off after the ball stops...no energy will be left in this mechanism. All the energy would have been gone to the boat and it would have got propelled in one direction since all the K.E from the ball will be used to do so.

Again, no idea what you're talking about. What is this "mechanism"? Is it part of the boat? You toss a ball onto a boat and all of its KE becomes part of the "boat + ball" system. (Of course, much of that KE will become random internal energy.)

But this is NOT happening practically...so I assume the law of conservation of momentum as wrong.

 

[Hootenanny]

Let me see if I can decipher your set up before we try an sort out your misunderstandings. You have a boat floating on the water. Attached to the boat is a vertical wall. You throw a ball against this wall.

Is this correct?

 

[dE_logics]

Yes till now.

 

[Hootenanny]

Yes till now.

So, now you launch a ball (from the boat) towards the wall (also on the boat). Yes?

 

[Doc Al]

Thanks, Hoot. Perhaps now we'll get somewhere.

You're in a boat, throwing a ball against a wall attached to the boat. Assuming you toss the ball in the "forward" direction and thus it bounces off to the rear, then yes the boat will be propelled forward. Of course, if you "catch" the ball (using a mechanism of your choosing), you've just canceled out that propulsion.

Much simpler would be to just throw the ball backwards off the end of the boat.

 

[dE_logics]

So, now you launch a ball (from the boat) towards the wall (also on the boat). Yes?

Yes.

But that's not the end.

 

[dE_logics]

You're in a boat, throwing a ball against a wall attached to the boat. Assuming you toss the ball in the "forward" direction and thus it bounces off to the rear, then yes the boat will be propelled forward.

...no why??...if this was so achieving this sort of propulsion system would have been a piece a cake!

Of course, if you "catch" the ball

I'm not catching the ball.

It has de-accelerated to a halt (relative to boat) using a magnet. So the ball is not stationary...but where did the energy go (if you assume the boat will stop)?

The impulse applied through this magnet to the boat will be higher than -
1) The collision to the wall
2) the impulse delivered by me to the ball

Do you agree?

 

[dx]

Yes.

But that's not the end.

1. What did you do next?
2. What happened?
3. What do you think should have happened?
4. Why?

Try to be as precise as possible.

 

[Hootenanny]

I'm not catching the ball.

It has de-accelerated to a halt (relative to boat) using a magnet. So the ball is not stationary...but where did the energy go (if you assume the boat will stop)?

How do you de-accelerate the ball without it completely coming to rest? What happens when it comes to rest relative to the boat? Does it not fall and hit the boat?

Where is the magnet positioned?

 

[dE_logics]

Ok...here it is -

Suppose a light ball collides with a heavy body...suppose a boat.

Depending on the difference between masses of the ball and boat, the ball will recoil.

If the boat is heavy, the the ball will recoil more...the reason for this is the law of conservation of K.E working in conjunction to law of conservation of momentum. The 2 are not the same thing...that's the problem.

When the ball collides with the boat, it delivers the same amount of impulse that was delivered to it, but not the energy, since K.E has an exponential relationship to velocity and leaner to mass while momentum is leaner to both, even though the rated impulse will be delivered to the boat through the ball, all the energy possessed by the ball will not be derived to the boat cause the boat has gained momentum by virtue of mass...i.e less velocity. Ultimately very less K.E.

The remaining energy will be transferred to the ball and seen as the recoil.


Now what I've done is for example...I'm on the boat and I've thrown the ball in the 'negative' direction...this will initially propel the boat in the positive direction.

If this ball collides with the boat, the boat will attain a velocity in the negative direction and it (the ball) will recoil.

If it again hits the boat after recoil the boat will now start moving in the positive direction...this will continue forever and there will be no net propulsion and the boat will simply resonate between 2 points.

Suppose the ball after recoil is moving to the positive direction (and the boat, consequently to the negative), assuming the ball has iron inside it, if I pull the ball (trying to stop it relative to the boat) through a solenoid and stop the solenoid after the ball has stopped, this will be different from a collision.

This time, all K.E possessed by the ball will be will be used to propel the boat in the positive direction...so instead of all the momentum being transferred from the ball to the boat, all the energy gets transferred. For the same reason this impulse given to the boat through this magnet will be more than the collision of the ball to the boat or the impulse given by me to the boat when I threw the ball resulting a net propulsion in one direction.

If things simply stop, the law of conservation of energy will be violated.

 

[Hootenanny]

You still haven't answered my questions.

 

[dE_logics]

How do you de-accelerate the ball without it completely coming to rest?

Take a solenoid, turn it off when the ball stops...or reduces in speed.

Does it not fall and hit the boat?

Fall?

Ok...my second last post has it all...