Difference between momentum and kinetic energy

[scionoftheindus]

Can anyone here tell me the difference between KE and momentum in layman terms..momentum =mv and KE = 1/2mv^2 ..
Both increase or decrease with mass and velocity.then what is the difference ?I read many explanations on the net but couldnt find an explanation which a common man can understand...the only difference I understood is KE is a scalar quantity where as momentum is a vector one.

 

[Raja.Pakistani]

Momentum is a vector quantity as you said mean it has a direction while kinetic energy scalar quantity i.e does not have direction. Momentum is the measurement of concentrated force that is moving in one specific direction over a period of time. Momentum depend on mass x velocity while kinetic energy depend on mass x(speed) . you pedal your bicycle and transfer mechanical energy from muscles to the KE of biycle and bicycle has KE because of its movement so KE of a moving object will depend on mass of object and its speed. The bigger the mass and the speed of the object the greater its kinetic energy.

Momentum is conserved i.e no loss of momentum in collisions and stay same before and after collision provided no external forces applied on it while there is loss of kinetic energy in collisions(Inelastic).

Two types of collisions

elastic collisions: momentum is conserved and there is no loss of Kinetic energy( example collisions of particles )
Inelastic collision: momentum is conserved but some of the kinetic energy is transferred to other forms i.e thermal or light,sound energy. Its most common collision we observe on daily basis http://www.bbc.co.uk/schools/gcsebi...of_particles/motion_of_particles/revision/3/#

 

[Moonlight]

First you have to understand, both are simply quantities and we can calculate both with mass and and velocities.
P = mv
K = 1/2mv^2 or K = P^2/2m.

Momentum is vectors. So if you have two bodies moving to different directions and velocities. You gotta add another vector to determine transfer of momentum. It follows the elastic collision.
And energy is ability to do work and it's not vector.

But remember one thing. If you have to calculate the change in velocity for two bodies in collision, don't use KE equations.

I hope it helps.

 

[Providence]

Can anyone here tell me the difference between KE and momentum in layman terms..momentum =mv and KE = 1/2mv^2 ..
Both increase or decrease with mass and velocity.then what is the difference ?I read many explanations on the net but couldnt find an explanation which a common man can understand...the only difference I understood is KE is a scalar quantity where as momentum is a vector one.

Momentum is always conserved. Kinetic Energy may not be ( energy is ).

Momentum is indicative of the force a body will exert on another while kinetic energy is energy possessed due to its motion and it's indicative of how much work the body can do.

Connection between them can be understood by thinking of momentum change giving force which would allow one energy form to change to another. Like kinetic energy to say potential energy of a spring or something ..

 

[untitled]

OK I will try to give you a an example that has been trolled on this forum time and time again

Take two normal full metal jacket bullets one a 5.56 NATO weighing 4 gm and the other 7.62 NATO weighing 10 gm. Imagine both travelling at a speed of say 50 m/sec. Now do the math for KE and momentum on both rounds. You will see the difference in both quantities.

 

[scionoftheindus]

Momentum is always conserved. Kinetic Energy may not be ( energy is ).

Momentum is indicative of the force a body will exert on another while kinetic energy is energy possessed due to its motion and it's indicative of how much work the body can do.

Connection between them can be understood by thinking of momentum change giving force which would allow one energy form to change to another. Like kinetic energy to say potential energy of a spring or something ..

Thanks.

 

[scionoftheindus]

Momentum is a vector quantity as you said mean it has a direction while kinetic energy scalar quantity i.e does not have direction. Momentum is the measurement of concentrated force that is moving in one specific direction over a period of time. Momentum depend on mass x velocity while kinetic energy depend on mass x(speed) . you pedal your bicycle and transfer mechanical energy from muscles to the KE of biycle and bicycle has KE because of its movement so KE of a moving object will depend on mass of object and its speed. The bigger the mass and the speed of the object the greater its kinetic energy.

Momentum is conserved i.e no loss of momentum in collisions and stay same before and after collision provided no external forces applied on it while there is loss of kinetic energy in collisions(Inelastic).

Two types of collisions

elastic collisions: momentum is conserved and there is no loss of Kinetic energy( example collisions of particles )
Inelastic collision: momentum is conserved but some of the kinetic energy is transferred to other forms i.e thermal or light,sound energy. Its most common collision we observe on daily basis http://www.bbc.co.uk/schools/gcsebi...of_particles/motion_of_particles/revision/3/#

Thnx

 

[scionoftheindus]

OK I will try to give you a an example that has been trolled on this forum time and time again

Take two normal full metal jacket bullets one a 5.56 NATO weighing 4 gm and the other 7.62 NATO weighing 10 gm. Imagine both travelling at a speed of say 50 m/sec. Now do the math for KE and momentum on both rounds. You will see the difference in both quantities.

First you have to understand, both are simply quantities and we can calculate both with mass and and velocities.
P = mv
K = 1/2mv^2 or K = P^2/2m.

Momentum is vetoers. So if you have o bodies mooing to different directions and velocities. You gotta add another vector to determine transfer of momentum. It follows the elastic collision.
And energy is ability to do work and it's not vector.

But remember one thing. If you have to calculate the change in velocity for two bodies in collision, don't use KE equations.

I hope it helps.

Thanks

 

[nForce]

Can anyone here tell me the difference between KE and momentum in layman terms..momentum =mv and KE = 1/2mv^2 ..
Both increase or decrease with mass and velocity.then what is the difference ?I read many explanations on the net but couldnt find an explanation which a common man can understand...the only difference I understood is KE is a scalar quantity where as momentum is a vector one.

Why do you do attention-seeking stunts like these ? I have seen the kind of threads you post. Your school text book is more than enough to answer this question. What a waste.

 

[scionoftheindus]

Why do you do attention-seeking stunts like these ? I have seen the kind of threads you post. Your school text book is more than enough to answer this question. What a waste.

School text book is not enough to answer this question...it is a question not everyone can answer..you fool what is there in this question that can attract attention..in fact such questions hardly attract anyone..you might have observed the number of posts in this thread.

Do you even know what kinetic energy and momentum are?

 

[nForce]

School text book is not enough to answer this question...it is a question not everyone can answer..you fool what is there in this question that can attract attention..in fact such questions hardly attract anyone..you might have observed the number of posts in this thread.

Do you even know what kinetic energy and momentum are?

School text books are more than enough. Didn't you study Newton's Second law of motion there ?

 

[Maarkhoor]

Momentum and kinetic energy are each always completely linked to the velocity of a moving object, so if you know the (relative) velocity and mass of an object then you always can calculate both, with KE increasing in quadratic fashion with respect to velocity increases while momentum merely grows with parallel linearity.

The momentum presents a truer picture of the striking "force" of an object, while the kinetic energy reflects how long that force will be applied in said collision if it is one that is not completely elastic. Since flesh is soft, the pain you feel on your skin is going to have a lot to do with the kinetic energy. But your bones are solid, so to the extent that a stricken bone remains structurally intact from any impact, it is only the momentum that will be relevant. Softer tissue tends to get moved out of the way as an object progresses through a collision, allowing momentum to continue to be conserved even with deeper penetration. In water an object moving three times faster will thus penetrate nine times deeper and kinetic energy rules the day. But if the same object hits solid concrete and both objects remain completely intact, then momentum is all that matters in terms of assessing the consequences of the collision.

Kinetic energy is actually just the energy associated with very low level time dilation (which is of course non-directional, thus why KE is a scalar) as prescribed in the relativistic equation for energy (via a Taylor series). In real life this manifests itself as force applied over a distance, and that same quadratically increasing distance with respect to velocity that it takes to create momentum is also what it takes going the other way when attempting to stop or slow a moving object.

 

[scionoftheindus]

Momentum and kinetic energy are each always completely linked to the velocity of a moving object, so if you know the (relative) velocity and mass of an object then you always can calculate both, with KE increasing in quadratic fashion with respect to velocity increases while momentum merely grows with parallel linearity.

The momentum presents a truer picture of the striking "force" of an object, while the kinetic energy reflects how long that force will be applied in said collision if it is one that is not completely elastic. Since flesh is soft, the pain you feel on your skin is going to have a lot to do with the kinetic energy. But your bones are solid, so to the extent that a stricken bone remains structurally intact from any impact, it is only the momentum that will be relevant. Softer tissue tends to get moved out of the way as an object progresses through a collision, allowing momentum to continue to be conserved even with deeper penetration. In water an object moving three times faster will thus penetrate nine times deeper and kinetic energy rules the day. But if the same object hits solid concrete and both objects remain completely intact, then momentum is all that matters in terms of assessing the consequences of the collision.

Kinetic energy is actually just the energy associated with very low level time dilation (which is of course non-directional, thus why KE is a scalar) as prescribed in the relativistic equation for energy (via a Taylor series). In real life this manifests itself as force applied over a distance, and that same quadratically increasing distance with respect to velocity that it takes to create momentum is also what it takes going the other way when attempting to stop or slow a moving object.

I got the point but if the same question is asked by a seventh or eighth grade student, he can't grasp these explanations...I wanted a simple everyday life example.

 

[Maarkhoor]

I got the point but if the same question is asked by a seventh or eighth grade student, he can't grasp these explanations...I wanted a simple everyday life example.

Only junior school teacher can explain to such student i am electrical engineer and have no experience how to make children understand such tricky topic.
Regards,

 

[scionoftheindus]

Only junior school teacher can explain to such student i am electrical engineer and have no experience how to make children understand such tricky topic.
Regards,

A genius is one who makes complicated things simple...just kidding regards