4-vector law of motion in different inertial frames

In summary, Newton's second law of motion in Minkowski space can be expressed as \bar{F}=m(c\gamma\dot{\gamma}, \gamma\dot{\gamma}\tilde{v}+\gamma^{2}\tilde{a}) where \dot{\gamma}=\frac{d\gamma}{dt}=\frac{\gamma^{3}}{c^{2}}\tilde{v}\cdot\tilde{a} and \tilde{v}(t) and \tilde{a}(t) represent 3-velocity and 3-acceleration. This law has the same form in all inertial frames when starting from the assumption that 4-momentum is a vector,
  • #1
Wox
70
0
Newton's second law of motion is given in Minkowski space by
[tex]\bar{F}=m(c\gamma\dot{\gamma}, \gamma\dot{\gamma}\tilde{v}+\gamma^{2}\tilde{a})[/tex]
where [itex]\dot{\gamma}=\frac{d\gamma}{dt}=\frac{\gamma^{3}}{c^{2}}\tilde{v}\cdot\tilde{a}[/itex] and [itex]\tilde{v}(t)[/itex] and [itex]\tilde{a}(t)[/itex] the 3-velocity and 3-acceleration. How can I show now that this law has the same form in all inertial frames?
 
Physics news on Phys.org
  • #2
Well, it depends on what you want to assume. If you start from 4-momentum being a vector, then the RHS is d/dτ of 4-momentum (that should be easy for you to show). That is sufficient to to establish it has the same form in any inertial frame.

If, instead, you are supposed to demonstrate by brute force, it will work that applying the Lorentz transform should produce the same form, but that will be a large amount of messy, error prone algebra.
 

What is the 4-vector law of motion in different inertial frames?

The 4-vector law of motion in different inertial frames is a fundamental law in physics that states that the laws of motion are the same in all inertial frames of reference. This means that the laws of physics, including Newton's laws of motion, are consistent and applicable in all frames of reference that are not accelerating.

What is a 4-vector?

A 4-vector is a mathematical vector that has four components: three spatial components and one time component. It is used in relativity to describe the position, velocity, and acceleration of an object in spacetime. In the context of the 4-vector law of motion, it represents the motion of an object in different inertial frames.

Why is the 4-vector law of motion important?

The 4-vector law of motion is important because it helps us understand how motion is perceived differently by observers in different frames of reference. It also allows us to make accurate predictions and calculations in situations where objects are moving at high speeds or in different frames of reference.

How does the 4-vector law of motion relate to special relativity?

The 4-vector law of motion is a fundamental principle of special relativity, which is a theory that describes the behavior of objects moving at high speeds or in different frames of reference. The law states that the laws of physics, including the laws of motion, remain the same in all inertial frames of reference, which is a key principle of special relativity.

Can the 4-vector law of motion be applied to non-inertial frames?

No, the 4-vector law of motion only applies to inertial frames of reference. In non-inertial frames, such as accelerating frames or frames rotating at a constant velocity, the laws of physics are not consistent and the 4-vector law of motion does not hold. In these cases, other laws and principles, such as the laws of gravitation and the principle of equivalence, must be used.

Similar threads

  • Special and General Relativity
Replies
11
Views
381
  • Special and General Relativity
Replies
23
Views
1K
  • Special and General Relativity
Replies
22
Views
1K
  • Special and General Relativity
Replies
2
Views
822
  • Special and General Relativity
Replies
10
Views
1K
  • Introductory Physics Homework Help
Replies
24
Views
1K
  • Special and General Relativity
Replies
14
Views
2K
  • Special and General Relativity
Replies
16
Views
1K
  • Special and General Relativity
Replies
1
Views
565
  • Special and General Relativity
Replies
16
Views
4K
Back
Top