Mass–energy relation
Answers are for parents and teachers.
1
A particle's kinetic energy is twice its rest energy. By what factor is its mass greater than its rest mass?
3
2
In a nuclear reaction the mass decreased by 2 g. What energy is released (c² = 9·10¹⁶ m²/s²)?
1.8·10¹⁴ J
3
A photon has energy 6·10⁻¹⁹ J. What is its momentum (c = 3·10⁸ m/s)?
2·10⁻²⁷ kg·m/s
4
A particle with rest energy 8 MeV moves at β = 0.6. What is its total energy in MeV?
10
5
Why is «if energy changes, mass changes too» not noticeable in daily life?
In Δm = ΔE/c² the value c² is huge, so for ordinary ΔE the change Δm is too small to measure.