Two particles have equal kenetic energies

  • Thread starter Thread starter napier212121
  • Start date Start date
  • Tags Tags
    Energies Particles
napier212121
Messages
3
Reaction score
0
if two particles have equal kenetic energies, do they have the same momentum?
 
Physics news on Phys.org
NO! Just because something has the same kinetic energy doesn't mean it has the same momentum. There are a number of factors that could affect it.
 
Kinetic energy of an object with mass m and velocity v is (1/2)mv2. Momentum is mv.

Take for example, an object with mass 4kg and speed 1 m/s. Its kinetic energy is (1/2)(4)(1)2= 2 Joules and its momentum is (4)(1)= 4 kgm/s. Take a second object with mass 1kg and speed 2 m/s. It has kinetic energy (1/2)(1)(2)2= 2 Joules also but its momentum is (1)(2)= 2 kgm/s.
 
Last edited by a moderator:
Originally posted by HallsofIvy
Kinetic energy of an object with mass m and velocity v is (1/2)mv<sup>2</sup>. Momentum is mv.

Take for example, an object with mass 4kg and speed 1 m/s. Its kinetic energy is (1/2)(4)(1)<sup>2</sup>= 2 Joules and its momentum is (4)(1)= 4 kgm/s. Take a second object with mass 1kg and speed 2 m/s. It has kinetic energy (1/2)(1)(2)<sup>2</sup>= 2 Joules also but its momentum is (1)(2)= 2 kgm/s.

Well, kinetic energy (for particles, as the question originally asked) is probably more likely to be K = (\gamma - 1) mc^2, i.e. relativistic kinetic energy, which reduces to the Newtonian expression in the limit of small v.
 

Thread 'Toponium Discovered'

Toponium is a hadron which is the bound state of a valance top quark and a valance antitop quark. Oversimplified presentations often state that top quarks don't form hadrons, because they decay to bottom quarks extremely rapidly after they are created, leaving no time to form a hadron. And, the vast majority of the time, this is true. But, the lifetime of a top quark is only an average lifetime. Sometimes it decays faster and sometimes it decays slower. In the highly improbable case that...
View full post »

Thread 'Dirac-Delta from Normalization of Continuous Eigenfunctions'

I'm following this paper by Kitaev on SL(2,R) representations and I'm having a problem in the normalization of the continuous eigenfunctions (eqs. (67)-(70)), which satisfy \langle f_s | f_{s'} \rangle = \int_{0}^{1} \frac{2}{(1-u)^2} f_s(u)^* f_{s'}(u) \, du. \tag{67} The singular contribution of the integral arises at the endpoint u=1 of the integral, and in the limit u \to 1, the function f_s(u) takes on the form f_s(u) \approx a_s (1-u)^{1/2 + i s} + a_s^* (1-u)^{1/2 - i s}. \tag{70}...
View full post »

Similar threads

Alpha Particle Kinetic Energy: Explained
Replies
6
Views
2K
A Why KE of Annihilation Electrons Differs?
Replies
11
Views
2K
I Probing into protons with high-energy particles
Replies
10
Views
2K
A Calculate the energy-loss straggling of particles using LISE++
Replies
0
Views
3K
A Why don't we see super-symmetric particles?
Replies
6
Views
2K
B I wonder about a particle's energy when mass is obtained or lost
Replies
2
Views
3K
I High energy tritons
Replies
4
Views
3K
I What kind of energy is released in a nuclear fusion reaction?
Replies
14
Views
3K
I Correlation between size and mass of particles
Replies
7
Views
2K
I Energy momentum of massless particles
Replies
1
Views
2K

Hot Threads

Recent Insights

Back
Top