Solve relativistic velocity in terms of momentum (vector equation)

In summary, the conversation discusses finding a simple way to solve a non-linear vector equation involving the formula \vec{p}=\frac{m_0}{\sqrt{1-\frac{|\vec{v}|^2}{c^2}}}\vec{v}. One approach suggested is to split the equation into three equations and use the magnitudes of the vectors, but this is complex. The solution proposed involves squaring the equation, solving for v^2, and then substituting it back into the square root in the original equation. This results in the equation \vec{v}=\frac{\vec{p}}{\sqrt{m_0^2+\frac{|\vec{p}|^2}{c^
  • #1
winstonyin
1
0
Given the formula [itex]\vec{p}=\frac{m_0}{\sqrt{1-\frac{|\vec{v}|^2}{c^2}}}\vec{v}[/itex], I'd like to make [itex]\vec{v}[/itex] the subject, so I can do a numerical approximation for some relativistic motion problem. I want to treat it as a vector equation, but since it is non-linear, the only way I can think of is to split it into 3 equations with [itex]|\vec{v}|^2=v_x^2+v_y^2+v_z^2[/itex]. This is however very complicated, though Mathematica gave me the answer analogous to the equation with only magnitudes of the vectors. Is there a simple way I can solve such kind of vector equations?

Edited 3 Dec:
Solution: [itex]\vec{v}=\frac{\vec{p}}{\sqrt{m_0^2+\frac{|\vec{p}|^2}{c^2}}}[/itex]
 
Last edited:
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  • #2
1. Square the equation to get p^2=f(v^2).
2. Solve this for v^2=g(p^2).
3. Put this nto the square root to replace the v^2 by p^2.
4. Rewrite the original equation with the new square root.
 

FAQ: Solve relativistic velocity in terms of momentum (vector equation)

1. What is the formula for relativistic velocity in terms of momentum?

The formula for relativistic velocity in terms of momentum is v = p / (m * gamma), where v is the velocity, p is the momentum, m is the mass, and gamma is the Lorentz factor.

2. How is relativistic velocity different from classical velocity?

Relativistic velocity takes into account the effects of special relativity, such as time dilation and length contraction, which can significantly affect the velocity of an object moving at high speeds. In contrast, classical velocity only considers the speed of an object without considering these relativistic effects.

3. Can the speed of an object ever exceed the speed of light?

No, according to the theory of special relativity, the speed of light is the maximum speed that any object can attain. Therefore, the speed of an object cannot exceed the speed of light, even when using the formula for relativistic velocity.

4. How does momentum affect an object's relativistic velocity?

As an object's momentum increases, its relativistic velocity also increases. This is because momentum is directly proportional to velocity in the equation v = p / (m * gamma). Therefore, the greater the object's momentum, the higher its relativistic velocity will be.

5. Can the relativistic velocity of an object ever be negative?

Yes, the relativistic velocity of an object can be negative. This means that the object is moving in the opposite direction of its momentum. For example, if an object has a momentum of -10 kg*m/s, it can have a relativistic velocity of -2 m/s. This is possible because the formula for relativistic velocity takes into account the direction of an object's momentum.

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