This is less of a strict math problem than me thinking my online teacher is wrong. I will, however, format the question as per PF's requirements, and I think it should be in this forum because it involves my coursework.(adsbygoogle = window.adsbygoogle || []).push({});

1. The problem statement, all variables and given/known data

Essentially, when should I use relativistic calculations (considering gamma in equations like momentum, speed, length, etc.)?

2. Relevant equations

γ = 1/sqroot(1 - v^2/c^2), and dependent equations

3. The attempt at a solution

My teacher says that this should only be used for cases where "it makes a difference", and uses "like, 99% of c" as his example. I was given a problem on a quiz in which a particle was traveling at 16% of c, I used the relativistic momentum (I was finding the De Broglie wavelength), and got the answer wrong (presumably because I used the relativistic momentum). In the example the problem showed, it used the regular definition of momentum.

SO- who screwed up? My answer was wrong enough for it to be counted wrong, which pretty much justifies my argument. The value of gamma at 16.6% of c is 1.014, which I think is an appreciable difference (1.4 percent). At 50% of c, which my teacher also seems to be discounting, gamma is 1.1547. 15.5% is definitely an appreciable difference.

What do you all think?

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Relativistic calculations - when to use them?

**Physics Forums | Science Articles, Homework Help, Discussion**