A subatomic particle X spontaneously decays into two particles, A and B, each of rest energy 1.40 × 10 2 MeV. The particles fly off in opposite directions, each with speed 0.827c relative to an inertial reference frame S.
-Which expression gives the momentum of particle A (relative to frame S)?

Question

Quizplus · Accepted Answer

The momentum of a particle can be calculated using the relativistic momentum formula: $ p = \frac{\gamma mv}{c} $, where $ \gamma = \frac{1}{\sqrt{1 - v^2/c^2}} $. Given the rest energy $ E_0 = 140 $ MeV, the rest mass $ m = \frac{E_0}{c^2} $. With $ v = 0.827c $, calculate $ \gamma $ and then the momentum $ p $. The correct calculation gives approximately 206 MeV/c.

A Subatomic Particle X Spontaneously Decays into Two Particles, a and B