Question

Can a body have momentum without energy?

Answer 1

I don't think so.

Answer 2

everything that is MOVING has energy (kinetic)associated with it
the expression being 1/2mv^2

Answer 3

Tell me a place where energy is not present, if you can answer this then any body can have momentum without energy

Answer 4

ajay when a particle has just escaped the pull of earth with escape velocity it has 0 energy right?
then it has no energy

Answer 5

shalini, according to einstein's equation[ E=mc^2] Everything that posses mass have energy,
As particle escapes from earth pull it has wasted abundend energy, and on the other hand it has gained alot of energy.
And energy never remains stable it will keep converting and possesing new form, so as it escapes its energy taked another form

Answer 6

So according to situation in space a body can have momentum without energy....
Think it

Answer 7

u are right in saying that there is no '0' energy state of any mass but the total mechanical energy(k.e+p.e)
has been converted to another satate in another system (thereby not losing any energy but converting it from one form to another)
as it is mechanical energy that it capable of creating motion in a system(remember first law of motion by newton)
at a point infinity when a body has escaped the earth it neither has p.e(gravitational to be specific)or k.e
yes it is transferred to another system in another form of enrgy according to theorey of relativity
but it has no motion hence no momemtum
so if a body has momentum meaning it has some MECHANICAL ENERGY
so yes u are right in saying taht in all cases it has some energy

check ur second post which contradicts ur first one!

Answer 8

salini i would like to correct you on that.. when you release a particle with escape velocity then this just only means that it has that much much kinetic energy to be converted into potential energy so that i can reach to any infinitely distant point. And at that point where you are saying, velocity is zero,THERE WOULD BE POTENTIAL ENERGY.!!

Answer 9

and no, momentum means you have velocity therefore kinetic energy.. so we cn't have momentum without energy, but converse is not true.

Answer 10

without energy is impossible.

Answer 11

@prakharji what type of potential energy?(definitely not gravitational p.e as it is no longer bound to earth)
if it has some p.e also is it capable of creating motion in the body at that escape point?
also the toatl MECHANICAL energy at infinity of an escape projectile is zero right?

Answer 12

no i don't think that a body can posses momentum without energy because for the momentum u require kinetic energy .

Answer 13

yes dear i'm talking about gravitational pot energy... and of course it is capable to create motion..we cannot define infinite, at any point in space a non zero force will always be there,however small in magnitude but will exist, n that gonna create the motion..

Energy is relative,zero mechanical energy does not mean absolute zero energy, don't forget we initially took potential energy to be negative and thats why our mechanical energy came out to be zero!

Answer 14

then at the point where body escapes pull of earth there is some mechanical energy in the form of potential energy?

Answer 15

well there is no a fixed point na after where you can say body escaped pull of earth, force is still acting on it everywhere.. by escape we just mean that it has sufficient velocity so that it does not return back even though force is still acting on it.... And guess what, at infinity where if you say velocity is zero, all the mechanical energy will potential energy whose magnitude will be zero, whereas the change in its magnitude through the whole process is -Gm/r ...

Answer 16

oh sorry, change in pot energy will be Gm/r not - Gm/r

Answer 17

ya so as u say total p.e=0 agreed ?(when body just escaped pull of earth)

Answer 18

at infinity p.e is zero.. yeah

Answer 19

are you clear now? (:

Answer 20

yes! thank u for responding!

Answer 21

Ok, friends tell me there will be only potential and kinetic energy will be acting all the time. where the other energy goes

Answer 22

Think practical, answer me. not that paper work which tell at infinity P.E. is 0.
How will you create infinity with an object, experiencing forces at every moment.....
Answer

Answer 23

first you should correct the way you are thinking of energy.. Energy DO NOT ACT on something.. and which kind of other energies are you talking about.. well if you wanna jump on modern physics ,thats another case..!

Answer 24

Not thats not another case, modern physics is a way of understanding, in which relativistic mass and energy acts. so practically speaking when we have to analysis the energy of a system then we have to take these thing in account. there after we will get more precious answer

Answer 25

which kind of other energies are you talking about? [you asked that in your 3rd last post]

Answer 26

no!! when we think practically,we don't put these things in account.okay!! what you are posting is contradicting to what you wanna say...! put your questions in straight forward manner.

Answer 27

My energy means simply a energy which can be converted, it is now dimension less, but according to situation it chooses dimension and find a distinct form.............
You all are talking about the energy posses by body due to its postion, but what about the body's internal energy?

Answer 28

we are only talking about mechanical energy because the question moves around momentum and other mechanical terms.. why are you trying to get into the body's thermodynamics..body will have internal energy but that does no need to be considered in this case as its internal energy (theoretically speaking) will not gonna change its motion! well if you wanna stick some sort of engine with it which gonna create thrust using body's thermal energy...then we can talk on that. :)