How Is the Momentum of an Electron Calculated at 0.8c?

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SUMMARY

The momentum of an electron traveling at 0.8c is calculated using the relativistic momentum formula, p = m0v/√(1-v²/c²), where m0 is the rest mass of the electron. The classical momentum equation, p = mv, is insufficient at high velocities, such as 80% of the speed of light. The correct calculation accounts for relativistic effects, which become significant at such speeds. Therefore, the momentum must be computed using the relativistic definition to achieve accurate results.

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Homework Statement


What is the magnitude of the momentum (in kgm/s) of an electron traveling at 0.8c

Homework Equations


p = mv

The Attempt at a Solution


see photo. I said A but the answers said B.
 

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pkc111 said:

Homework Statement


What is the magnitude of the momentum (in kgm/s) of an electron traveling at 0.8c

Homework Equations


p = mv
p=mv is the classical approximatation accurate only for low speeds.

80% light speed is certainly not a low speed!

What is the relativistic definition of momentum?
 
Thank you!
 
pkc111 said:
What is the magnitude of the momentum (in kgm/s) of an electron traveling at 0.8c
it should be m0v/√(1-v2/c2),
m0 being the rest mass of the electron.
​
 
Last edited:

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