Chapter 29, Problem 81GP

The rest energy, m₀c², of a particle with a kinetic energy K and a momentum p can be determined as follows:

     $m_0{c}_2=\frac{{\left(pc\right)}^2-K^2}{2K}$

Suppose a pion (a subatomic particle) is observed to have a kinetic energy K = 35.0 MeV and a momentum p = 5 61 × 10⁻²⁰ kg³m/s = 105 MeV/c. What is the rest energy of the pion? Give your answer in MeV.