Homework help - Models.

[physica]

If I was using this model for gravity, x=Earth's core, Y=Sun, Z=space dust/matter

 

If I was using this model for perpetual motion, X=positive polarity, Y=positive polarity, Z=negative polarity

 

Like my earlier diagram model.

 

I am 99% logically sure I could make a simple device, that would create energy literally out of fresh air using this model and the concept and idea that goes with it.

Would something with no applied energy, e.g. batteries etc, that continually vibrates be classed has perpetual motion?

You struggle to create the most simple models, your maths wouldn't get you through 1st year undergraduate physics and you struggle with newtons laws (you still seem to fail to understand normal reaction forces). But you're 99% sure you've broken the laws of thermodynamics and can produce a model that will create energy from nothing. I'm sorry, I have tried to encourage you when you started asking about models, I've even sketched out a simple for you and given you a step by step process of creating a model but I have to say, this is sheer delusion that has been born from a complete lack of understanding of physics.

[Relative]

I am sorry , some one agreed with my earlier model has been crude but describing vague , so I improved the model and added some simple formula.

 

With formula explanation , of the values.

 

My model explains a simple equilibrium between two values and each action.

 

X been repelled by Y and Y been repelled by X , Z is attracted to both X and Y, X the nearer to Z having stronger force on Z.

 

Z also been attracted to Y, and Y attracted to Z.

 

The distance between the objects , deemed by volume of x,y,z, and their energies contained.

 

I am confused, because I try to improve on the maths, using formulas, I am sorry from my perspective view I thought it was easy to understand.

 

How is my model not a model when I have explained the parameters to the diagram?

Change it to magnetic interactions if you like

[Ophiolite]

I am sorry , some one agreed with my earlier model has been crude but describing vague , so I improved the model and added some simple formula.

No, You didn't improve it: you ****ed it up.

You didn't add a formula, you added a concatenation of meaningless letters. You don't know what a formula is, because you won't frigging undertake the study several of us have recommended.

 

 

My model explains a simple equilibrium between two values and each action.

In your dreams, but not on any planet I inhabit.

 

X been repelled by Y and Y been repelled by X , Z is attracted to both X and Y, X the nearer to Z having stronger force on Z.

 

Z also been attracted to Y, and Y attracted to Z.

What is the nature of the repulsion and the attraction between these objects? The strong force, gravity, electromagnetism? What?

 

How does the repulsion vary with distance? (Does it vary with distance?) If so, is it a linear relationship; an inverse relationship; something more complex? If you cannot specify that then you do not have a model.

 

 

The distance between the objects , deemed by volume of x,y,z, and their energies contained.

That sentence is devoid of meaning. A distance cannot be deemed by volume and very definitely not by volume and their contained energies. That is just silly nonsense. Stop making stuff up and educate yourself.

 

 

I am confused,

At last we are in agreement.

 

 

because I try to improve on the maths, using formulas

You don't understand any of this well enough to be thinking about improving anything. And you are not using formulas. Strings of letters are not formulas.

 

 

How is my model not a model when I have explained the parameters to the diagram?

 

You have not explained it. You have made some meaningless statements. Any points that can be understood by your readers are wrong, or contradictory.

 

Please go away and learn the basics. Please. Really, please. We've pointed you to where. Ask questions about what you are studying, not about fantasies you are dreaming up. (And the floor is pushing back at you.)

Change it to magnetic interactions if you like

[imatfaal]

!

Moderator Note

 

Relative

 

Phuzzwood, Fysica, Ofiolite and others have all tried to keep this thread at a rational and productive level but you insist on returning to flights of fancy - so I will now re-iterate, I will not allow a thread in homework help to go off on mad tangents; either you stick to known science and how we generate physical models from ideas, known relations, and mathematical logic or this thread gets locked.

 

[swansont]

If I was using this model for gravity, x=Earth's core, Y=Sun, Z=space dust/matter

 

If I was using this model for perpetual motion, X=positive polarity, Y=positive polarity, Z=negative polarity

 

Like my earlier diagram model.

 

I am 99% logically sure I could make a simple device, that would create energy literally out of fresh air using this model and the concept and idea that goes with it.

Would something with no applied energy, e.g. batteries etc, that continually vibrates be classed has perpetual motion?

 

 

The earth's core, the sun and space dust are objects, not properties of objects. x=y makes no sense, because they are not the same thing.

 

For polarity, we often use + and -, or we use a vector notation.

 

What you're doing here is like jabbering and pretending it's a foreign language. But even though it sounds a little like that language to you, it's still gibberish to someone who speaks it. You need to go learn the language.

[Relative]

!

Moderator Note

 

Relative

 

Phuzzwood, Fysica, Ofiolite and others have all tried to keep this thread at a rational and productive level but you insist on returning to flights of fancy - so I will now re-iterate, I will not allow a thread in homework help to go off on mad tangents; either you stick to known science and how we generate physical models from ideas, known relations, and mathematical logic or this thread gets locked.

 

Thank you for giving me the warning and giving me chance to continue with the thread has long is it is on track to models.

 

Ok, I will only talk current models, and avoid all other subject matter, although it was my homework, I will now do the homework you provide.

 

 

I will look back now in the thread to find the model you suggested to look at. I am sorry for going off in my own little world.

''A square mass sliding on a inclined plane is a good exercise:''

Would the first parameters be correct in this diagram?

And my meaning of parameter is this definition - ''a numerical or other measurable factor forming one of a set that defines a system or sets the conditions of its operation.''

[swansont]

 

block.jpg

Would the first parameters be correct in this diagram?

 

No. What is the vector labeled "Force" supposed to represent?

 

What should be there is the force the incline exerts and gravity. Neither of which could be the vector "Force" you have.

[physica]

relative, it is good that you're starting to get somewhere. There is 3 forces but velocity isn't one. Friction is correct, there are two other forces acting on the block. Think about this for a little while. The force keeping the block on the slope, is it always at a right angle to the slop or does it depend on the angle? Everyday experience tells us that a slope at 90 degrees would not result in the block staying on the slope. So there must be some relationship between the direction of the force keeping the block on the slope and the angle of the slope. Next step, list the three forces and draw a correct force diagram with it. The three forces are:

 

1. friction

2. ?......

3. ?......

 

Keep going you're on the right path

[Relative]

relative, it is good that you're starting to get somewhere. There is 3 forces but velocity isn't one. Friction is correct, there are two other forces acting on the block. Think about this for a little while. The force keeping the block on the slope, is it always at a right angle to the slop or does it depend on the angle? Everyday experience tells us that a slope at 90 degrees would not result in the block staying on the slope. So there must be some relationship between the direction of the force keeping the block on the slope and the angle of the slope. Next step, list the three forces and draw a correct force diagram with it. The three forces are:

 

1. friction

2. ?......

3. ?......

 

Keep going you're on the right path

''Everyday experience tells us that a slope at 90 degrees would not result in the block staying on the slope. So there must be some relationship between the direction of the force keeping the block on the slope and the angle of the slope. ''

 

 

I do not understand, the only force I can see is vertically down. Weight of object, making that force.

 

Friction holding the object from sliding, <resistance>, and the direction and the velocity created by the angle of descent and surface friction.

 

Do I see that correctly?

all the arrows represent force direction that the pivot point of contact makes.

 

There is two boxes in this diagram, the smaller green one is sliding, the larger is tumbling.

 

 

 

What am I missing?

 

why does it need anything else?

i should of asked what are we trying to work out?

[physica]

I do not understand, the only force I can see is vertically down. Weight of object, making that force.

 

Friction holding the object from sliding, <resistance>, and the direction and the velocity created by the angle of descent and surface friction.

You have it!!!! so the weight acting vertically down but if you alter the axis so the x direction is parallel to the slope it simplifies the model and all you have to worry about is motion in the x-axis but we will cross that bridge when we come to it. Now we know that blocks can stand still on slopes. draw the two force vectors on the diagram. You will have weight pushing down and friction pushing up to the left. in order for the block to stay still the vectors will add up to zero so what direction is the last force vector pointing and what is it called?

 

forget pivot points as there is no torque. just focus on those three vectors.

Edited September 1, 2014 by physica

[Relative]

You have it!!!! so the weight acting vertically down but if you alter the axis so the x direction is parallel to the slope it simplifies the model and all you have to worry about is motion in the x-axis but we will cross that bridge when we come to it. Now we know that blocks can stand still on slopes. draw the two force vectors on the diagram. You will have weight pushing down and friction pushing up to the left. in order for the block to stay still the vectors will add up to zero so what direction is the last force vector pointing and what is it called?

 

forget pivot points as there is no torque. just focus on those three vectors.

I do not think I understand, are you asking what force makes the block not slide and be static?

 

less weight or more friction by surface material!.

 

The block always wants to fall because of gravity, the force, is the weight, unless you consider the surface friction to be a force.

 

 

I am sorry I can not see any other force involved.

[physica]

I do not think I understand, are you asking what force makes the block not slide and be static?

 

less weight or more friction by surface material!.

 

The block always wants to fall because of gravity, the force, is the weight, unless you consider the surface friction to be a force.

 

 

I am sorry I can not see any other force involved.

This is where maths starts to lead us. We know that blocks can stay stationary on a slope, this is one possible parameter for the model. This means that the sum of force vectors will equate to zero. I'm having to repeat myself but draw the block with the weight force vector and the friction force vector. After you've done this you will see that there has to be another vector in order for all the vectors to equate to zero. This is called the normal force and is a result of Newton's third law. The most irritating thing about this is that I've drawn a force diagram of a block on a slope earlier on this thread and sent it too you via private message.

[Relative]

This is where maths starts to lead us. We know that blocks can stay stationary on a slope, this is one possible parameter for the model. This means that the sum of force vectors will equate to zero. I'm having to repeat myself but draw the block with the weight force vector and the friction force vector. After you've done this you will see that there has to be another vector in order for all the vectors to equate to zero. This is called the normal force and is a result of Newton's third law. The most irritating thing about this is that I've drawn a force diagram of a block on a slope earlier on this thread and sent it too you via private message.

There would be no point in me just re drawing your diagram and copying it. You want me to put the upwards arrow for normal force representation, Fn, but I am still failing to see where the normal force comes from, you say the ground, how does the ground emit any sort of force?

Are you saying the object pushes on the surface and the surface pushes back?

 

Like this? but obvious friction axis angled.

[physica]

You're getting there. Add up the vectors. What your force diagram is saying is that the block can only move up the slope as the friction is pointing up the slope. Both normal and frictional vectors are correct. however, you have to rethink the weight vector. We know that the weight vector will push the block down the slope under certain angles of the slope. Therefore the weight has to oppose the friction (and in some cases over power it) and also oppose the normal force in-turn keep it on the slope.

Edited September 1, 2014 by physica

[Ophiolite]

Are you saying the object pushes on the surface and the surface pushes back?

Newton's Third Law: to ever action there is an equal and opposite reaction. Do you still wish to maintain it is not true?

[Relative]

You're getting there. Add up the vectors. What your force diagram is saying is that the block can only move up the slope as the friction is pointing up the slope. Both normal and frictional vectors are correct. however, you have to rethink the weight vector. We know that the weight vector will push the block down the slope under certain angles of the slope. Therefore the weight has to oppose the friction (and in some cases over power it) and also oppose the normal force in-turn keep it on the slope.

You want me to angle the gravity axis , in accordance to the slope, I do know what you saying, and understand what you are saying, but the gravity vector would always point down regardless of angle.

 

 

 

Changing the angle of the slope only changes what you call the Fn, not the direction of gravity.

 

 

''Newton's Third Law: to ever action there is an equal and opposite reaction. Do you still wish to maintain it is not true?''

 

 

Well if science thinks the ground pushes back then yes. But another story, I got stick too these basic physics models,

[studiot]

This thread is about models.

 

Models can be thought of as a representation of a particular situation (in this case a block sliding down an incline).

 

I suggest you start with a simpler situation to represent.

 

Say you start with the block sitting on a flat level table.

 

Will it move by itself?

 

Will it fall to the floor?

 

when you have got this one sorted then tip the table so you can go on to an inclined plane.

[physica]

gave you a plus one for this as you've stuck with it and got somewhere. The G and the red normal force and red frictional force are correct. Now the axis is tilted so normal force points in the positive y direction and the friction is in the negative x direction. Now applying Newton's second law give me the magnitude of the forces. Do not resolve them in vector form yet. Because you haven't resolved them in vector form do not worry if they don't add up to zero.

 

Newton's second law force=(mass)(acceleration) acceleration= gravity

 

so

 

weight= ?

 

normal force= (weight in the projection of the weight perpendicular to the surface the block is acting on)

 

friction= (mew)(normal force)

Edited September 1, 2014 by physica

[Relative]

This thread is about models.

 

Models can be thought of as a representation of a particular situation (in this case a block sliding down an incline).

 

I suggest you start with a simpler situation to represent.

 

Say you start with the block sitting on a flat level table.

 

Will it move by itself?

 

Will it fall to the floor?

 

when you have got this one sorted then tip the table so you can go on to an inclined plane.

The diagram above shows axis shift and level at the same time, 0 been level.

 

Will a stationary object on a flat surface move , no, unless there is acting force.

 

Will a stationary object fall to floor if on a flat table, no, because the density of the table prevents it from falling.

 

Tilt the table, the weight of the object is shifted.

gave you a plus one for this as you've stuck with it and got somewhere. The G and the red normal force and red frictional force are correct. Now the axis is tilted so normal force points in the positive y direction and the friction is in the negative x direction. Now applying Newton's second law give me the magnitude of the forces. Do not resolve them in vector form yet. Because you haven't resolved them in vector form do not worry if they don't add up to zero.

 

Newton's second law force=(mass)(acceleration) acceleration= gravity

 

so

 

weight= ?

 

normal force= (weight in the projection of the weight perpendicular to the surface the block is acting on)

 

friction= (mew)(normal force)

Ok ty for the help, I will try to work it out later when I completely get my head around what you are asking.

 

I already understand F=MA, I still do not understand what the normal force suppose to be, or is created by.

 

But I will give it ago later tyvm.

Edited September 1, 2014 by Relative

[studiot]

 

I still do not understand what the normal force suppose to be, or is created by.

 

Which is why I suggested a simpler scenario.

 

 

The diagram above shows axis shift and level at the same time, 0 been level.

 

Yes, but I did not ask for a diagram (yet).

 

 

Will a stationary object on a flat surface move , no, unless there is acting force.

 

Exactly, not unless I push it or

 

Can you think of any other situation in which the block would not move sideways?

 

(don't forget it is sitting on a horizontal table)

 

 

 

 

 

Will a stationary object fall to floor if on a flat table, no, because the density of the table prevents it from falling.

 

 

 

I didn't mention density, why do you think this has anything at all to do with the situation?

 

Please just try to follow detail as presented and don't introduce other material.

 

 

 

Tilt the table, the weight of the object is shifted.

 

 

I said we would move on to this one when you have the horizontal situation sorted.

 

Do you think we have it sorted?

[Relative]

 

Which is why I suggested a simpler scenario.

 

 

Yes, but I did not ask for a diagram (yet).

 

 

Exactly, not unless I push it or

 

Can you think of any other situation in which the block would not move sideways?

 

(don't forget it is sitting on a horizontal table)

 

 

 

 

I didn't mention density, why do you think this has anything at all to do with the situation?

 

Please just try to follow detail as presented and don't introduce other material.

 

 

I said we would move on to this one when you have the horizontal situation sorted.

 

Do you think we have it sorted?

''Can you think of any other situation in which the block would not move sideways?''

 

Relative to the observer, sideways movement could also be achieved by moving the table.

 

In no instant will the block not move sideways with enough applied force?

''Can you think of any other situation in which the block would not move sideways?''

 

Relative to the observer, sideways movement could also be achieved by moving the table.

 

In no instant will the block not move sideways with enough applied force?

Unless you are referring to Up and down, and the same, enough applied force in one direction, will result in the opposite direction for the block, Newtons third law.

And heat rises, so does all forms of energy rise?

And i have done a similar table diagram anyway

 

Sorry for asking this moderators but it is important to some other homework.

Buoyant gases rise because they thermodynamically charge faster .....?

[studiot]

 

Relative to the observer, sideways movement could also be achieved by moving the table.

 

Good one I hadn't thought of that. +1 for keeping with it.

 

 

But what I meant was

 

One force will push the block side ways.

 

Two forces in applied in the same direction will push it faster

 

but

 

Two (equal) forces applied in opposition will hold it in place so it does not move.

 

Do you agree?

Edited September 2, 2014 by studiot

[Relative]

 

Good one I hadn't thought of that. +1 for keeping with it.

 

 

But what I meant was

 

One force will push the block side ways.

 

Two forces in applied in the same direction will push it faster

 

but

 

Two (equal) forces applied in opposition will hold it in place so it does not move.

 

Do you agree?

Yes I agree, creating a vice like grip on a block will hold it in place, although enough force , will still move the block and the vice.

 

But in general talk on subject, yes.

''Two (equal) forces applied in opposition will hold it in place so it does not move.''

 

To make something that is truly stationary, the force would need to be isotropic.

And if the block is on Earth, even though you have contained your block with vice like force, the block is still moving, because the planet is moving.

Edited September 2, 2014 by Relative

[studiot]

 

But in general talk on subject, yes.

 

 

Good we are moving forwards.

 

In fact we have the beginnings of a model - the object of this thread.

 

When we make a model we strip away unecessary complications and try to extract one or a few simple principles.

 

That is what we have done here.

 

"A body can be held in place by two equal opposing forces"

 

So we draw the block and two arrows to represent the forces.

 

It does not matter how the forces are applied.

It may be a wind blowing

It may be that the block is made of iron and the forces is applied by a martian with a magnet

It may be that Von Guericke had hitched his horses to the block (that is an interesting demonstration I will tell you about later)

 

We have the beginnings of Newton's third law

 

When two material bodies A and B interact so that body A applies a force on body B,

body always B applies a counterforce on body A.

 

In other words, in the material world forces always come in pairs.

[Relative]

 

Good we are moving forwards.

 

In fact we have the beginnings of a model - the object of this thread.

 

When we make a model we strip away unecessary complications and try to extract one or a few simple principles.

 

That is what we have done here.

 

"A body can be held in place by two equal opposing forces"

 

So we draw the block and two arrows to represent the forces.

 

It does not matter how the forces are applied.

It may be a wind blowing

It may be that the block is made of iron and the forces is applied by a martian with a magnet

It may be that Von Guericke had hitched his horses to the block (that is an interesting demonstration I will tell you about later)

 

We have the beginnings of Newton's third law

 

When two material bodies A and B interact so that body A applies a force on body B,

body always B applies a counterforce on body A.

 

In other words, in the material world forces always come in pairs.

I am unsure still sorry,

 

example- I have a draw that is stuck, I decide to leverage it open using a flat ended screw driver, the force comes from me, transferred through the screw driver, forcing the draw to open.

 

Where would the second force be in this example if it comes in pairs?