I dont understand this concept , how can energy be negative?
someone (netsavvy) says that if one spends more enrgy than possessed , enrgy can be negaitive.
Can any1 tell me how to do this?, then i dont hav to spend money on food

7 COMMENTS

when an object cools down? the change in energy is negative .

well…forget energy. try understanding negative numbers. what is -1. can u show it on ur finger? negative numbers were .. well even i dont know how to explain..its there in my mind..its like…if u have taken 100 Rupees(Im an indian :D) and u have spent 200 Rupees, the money with you is -100 Rs. that is, IF u get 100 Rs more, u will be even. The same with energy, if more energy is spent than possessed, then energy is negative. also, negative energy can be a convention…attractive energy is negative, its just a convention..to differenciate from positive energy…dont worry about the minus sign too much. dont think Minus means negative, imaginary etc etc etc…its just a way of denoting sumthing which is NOT positive!
ðŸ™‚
I hope i was clear, i just spoke whatever came to my mind!!

Generally, matter and speed and so on is positive energy, but gravitational potential energy is done differently. The reference point, where the potential energy would be zero, is counted as infinitely far away, so the potential energy is always negative.
For example, when a spaceship has travelled infinitely far away from Earth, its potential energy is zero. Since the gravity has had an infinitely long time to affect its speed, the kinetic energy, and the total energy, is zero. Now, when the ship was first launched, the potential energy was negative, and the kinetic energy was positive. Since these must add to zero, this can be used to calculate the minimum escape velocity.

I have a concept which I didnot read from any specific book. So read it carefully and give your response at padhi_ss44@yahoo.com
I have related energy with stability. Energy is directly related with stability. More is the energy(any form) contained in a body, less is its stability. If a body is just stable/just unstable, than its energy is zero. It is unstable if it have positive energy.
Think of a book placed on a table. If the table were not be there, will the book remain at the same place? No. It is because it have positive energy. (you can argue that the potential energy is negative, but my dear, the potential energy of the earth-book system is negative. But the energy of the book is positive.The negative energy of the earth-book system tells us that the earth and book will not be separated if they are left free.)
Now consider the case of an electron in the orbit of an atom. Is it free to go out of the atom? No. If you want to make it move out of the atom, you have to make its energy greater than zero( atleast zero) and for this you have to supply it some energy. So what was its energy when it was in the orbit. Think of , and you will get your answer.

When we throw up some object from the ground, we do give energy to it.
As it goes up and up, its speed decreases. That is, it is loosing its energy. At one stage it looses all the energy that we gave it to it.
So we say that it has increased its potential energy by loosing its kinetic energy.
But it returns back.
On its return path, it looses its potential energy and increases its kinetic energy.
When it reaches the ground it has lost all its potential energy.
So far, we have not said any thing about negative energy.
But imagine now that there is a well and the object falls into the well on its return path.
How will you describe the potential energy of the object? Its potential energy on the ground is already zero.
There fore, we say as the object goes inside the well its potential energy is negative.
However, if we had thrown the object from the bottom of the well, then we will say that at the bottom of the well, potential energy is zero and only if it goes inside the bottom of the well, we will say that its potential energy is negative.
Thus the potential energy can be positive or negative according to our definition of zero potential.
If at infinite distance from the center of earth, the potential energy is taken to be zero, the potential energy becomes more and more negative when the point approaches earthâ€™s center.

when an object cools down? the change in energy is negative .

It’s like the battery has a negative and a positive side. If you believe in positive energy then negative has to exist also.

well…forget energy. try understanding negative numbers. what is -1. can u show it on ur finger? negative numbers were .. well even i dont know how to explain..its there in my mind..its like…if u have taken 100 Rupees(Im an indian :D) and u have spent 200 Rupees, the money with you is -100 Rs. that is, IF u get 100 Rs more, u will be even. The same with energy, if more energy is spent than possessed, then energy is negative. also, negative energy can be a convention…attractive energy is negative, its just a convention..to differenciate from positive energy…dont worry about the minus sign too much. dont think Minus means negative, imaginary etc etc etc…its just a way of denoting sumthing which is NOT positive!

ðŸ™‚

I hope i was clear, i just spoke whatever came to my mind!!

Generally, matter and speed and so on is positive energy, but gravitational potential energy is done differently. The reference point, where the potential energy would be zero, is counted as infinitely far away, so the potential energy is always negative.

For example, when a spaceship has travelled infinitely far away from Earth, its potential energy is zero. Since the gravity has had an infinitely long time to affect its speed, the kinetic energy, and the total energy, is zero. Now, when the ship was first launched, the potential energy was negative, and the kinetic energy was positive. Since these must add to zero, this can be used to calculate the minimum escape velocity.

I have a concept which I didnot read from any specific book. So read it carefully and give your response at padhi_ss44@yahoo.com

I have related energy with stability. Energy is directly related with stability. More is the energy(any form) contained in a body, less is its stability. If a body is just stable/just unstable, than its energy is zero. It is unstable if it have positive energy.

Think of a book placed on a table. If the table were not be there, will the book remain at the same place? No. It is because it have positive energy. (you can argue that the potential energy is negative, but my dear, the potential energy of the earth-book system is negative. But the energy of the book is positive.The negative energy of the earth-book system tells us that the earth and book will not be separated if they are left free.)

Now consider the case of an electron in the orbit of an atom. Is it free to go out of the atom? No. If you want to make it move out of the atom, you have to make its energy greater than zero( atleast zero) and for this you have to supply it some energy. So what was its energy when it was in the orbit. Think of , and you will get your answer.

When we throw up some object from the ground, we do give energy to it.

As it goes up and up, its speed decreases. That is, it is loosing its energy. At one stage it looses all the energy that we gave it to it.

So we say that it has increased its potential energy by loosing its kinetic energy.

But it returns back.

On its return path, it looses its potential energy and increases its kinetic energy.

When it reaches the ground it has lost all its potential energy.

So far, we have not said any thing about negative energy.

But imagine now that there is a well and the object falls into the well on its return path.

How will you describe the potential energy of the object? Its potential energy on the ground is already zero.

There fore, we say as the object goes inside the well its potential energy is negative.

However, if we had thrown the object from the bottom of the well, then we will say that at the bottom of the well, potential energy is zero and only if it goes inside the bottom of the well, we will say that its potential energy is negative.

Thus the potential energy can be positive or negative according to our definition of zero potential.

If at infinite distance from the center of earth, the potential energy is taken to be zero, the potential energy becomes more and more negative when the point approaches earthâ€™s center.

negative energy exists only relative to some other body.