Can something have energy without having momentum? Can something have momentum without energy?

Answer 1

Yes something can have energy without having momentum, because energy comes in two basic types: kinetic or potential energy. Kinetic energy is always associated with momemtum because it is the energy involved in motion, whereas potential energy has to do with the energy stored in a body that can "potentially" do work.

However, you can NOT have momentum without having energy. That would be a contradiction in definition.

Answer 2

A lot of people are giving good answers here; but I think THE answer to this question revolves around being careful about defining terms (a problem that physicists have always had, and still do. This is a case in point.). First, the people who pointed out the distinction between potential and kinetic energies in classical (i.e. non-quantum mechanical) physics are absolutely right. Kinetic energy can be thought of as the energy of motion, and it makes intuitive sense that, all things being equal, a thing moving fast has more energy than a thing moving slowly. Potential energy, on the other hand, is the energy of position, like gravity (for instance). This is a little more slippery subject (intuitively), but still, think about it and you should be able to 'feel' that there must be some sort of energy associated with (for instance) the Earth's pull on a satellite orbiting in space. This gravitational potential energy will be different when the satellite is say, 10 miles up than it would be at 1000 miles up, wouldn't it? But the main term that has NEVER been closely (or adequately) defined in physics is 'energy' itself. Putting aside quantum mechanical systems (in which energy is defined by (and more or less replaced by) a mathematical creature called the Hamiltonian, a bit beyond the scope of this question, or this list) the word 'energy' is defined as the amount of 'work' a force does in moving a particle between two points. But what is 'work'? Work is a measure of the amount the energy of a particle changes in moving between the two points in question. Kinda circular, no? But the funny thing is, as circular as this argument is, it seems to be true! So far nobody has ever come up with a better one, at least as far as predicting how stuff will behave in the world (excepting quantum mechanical systems, which are just plain wierd!).

In answer to your specific questions, yes in both cases. The reason is that the TOTAL energy of a system is defined as the sum of kinetic and potential energies. While the kinetic energy of a particle will always be greater than or equal to zero (since KE=p^2/2*m) the potential energy can be anything, including negative (another wierd idea, I know). So a particle can have non-zero momentum and zero TOTAL energy if the potential energy is equal to the negative of the kinetic energy. And a particle can have non-zero energy with a momentum equal to zero as long as the potential energy is non-zero.

This may be more than you were asking, but you'll need it on your next test anyways.

Answer 3

physics dude is right on with his answer. he forgot to mention another case of having energy but no momentum in that everything has intrinsic energy through the mass energy equivalence. So something at rest has no momentum but has energy =c*mass^2.
But that energy won't be accessible unless there is a nuclear reaction.

Answer 4

Momentum is the product of the mass by velocity.

Regarding energy you need to be more specific. Obviously a body m can have potential energy and its velocity will be 0. Then momentum of this body is zero, but it has potential energy if it is sitting on top of the mountain.

If you are referring to kinetic energy, then KE is associated with velocity, KE = 0.5 m * v2. So any body with KE has momentum.

Answer 5

I think franco is right. There is nothing which have either momentum or energy. If an object have momentum it also have energy and vice versa.
photons are the massless particles but they have both energy and momentum. Thats kind of weired to think if p=mv and E=mc^2+1/2mv^2 then how does photon who are massless have energy and momentum. Relativistic physics show that. If you want to know more about energy and momentum of particle you can read any modern physic book .

Answer 6

Energy without momentum: a loaded spring.
Momentum without energy:no, because any motion will result in a energy.

Answer 7

Everything is moving in the universe, therefore everything has momentum, everything has energy, some things just have more energy than others.
There is no place in the universe that has no energy,if there is such a place then it contains no matter no light, no subatomic particles such a place would be unobservable.

Answer 8

Above is right. i might in simple terms desire to function that power transmitted by skill of massless waves might have power and no momentum on account that there is not any mass. Gamma radiation is extremely energetic, yet momentum is velocity x mass.

Answer 9

Write down what you know about each.

Energy = m x v^2 and

Momentum = m x v

So something cannot have one without the other.