ehild

v=0.9999c. 1-v^2/c^2 =1-0.9999^2. It is better to expand it as (1-0.9999)(1+0.9999) = 1.9999 E-4.

[tex]mc^2=\frac{100 m_0c^2}{\sqrt{1.9999}}[/tex]

KE=mc²-m₀c², about 70 times the rest energy.

ehild