Question

Physicists often measure the momentum of subatomic particles moving near the speed of light in units of MeV/c, where c is the speed of light, and 1 MeV = 1.6 ✕ 10−13 kg · m2/s2. Based on this, what are the units of momentum for a high-speed subatomic particle in terms of fundamental SI units?

Answer 1

Answer:

kg m/s

Explanation:

e = Charge = C

V = Voltage = $\dfrac{N}{C}m$

c = Speed of light = m/s

Momentum is given by

$\dfrac{MeV}{c}=\dfrac{e\times V}{c}\\\Rightarrow \dfrac{MeV}{c}=\dfrac{C\times \dfrac{N}{C}\times m}{m/s}\\\Rightarrow \dfrac{MeV}{c}=Ns\\\Rightarrow \dfrac{MeV}{c}=kg\times \dfrac{m}{s}\times s\\\Rightarrow \dfrac{MeV}{c}=kg\cdot m/s$

The unit of MeV/c in SI fundamental units is kg m/s