Dorminton

force dose not equal mass.

$m={\frac {f}{a}}={\frac {w}{g}}$

mass in special relativity

$m={\frac {\sqrt {E^{2}-\left(pc\right)^{2}}}{c^{2}}}$

The relativistic mass equation is the formula for E divided by c²

$m_{\mathrm {rel} }={m \over {\sqrt {1-{v^{2} \over c^{2}}}}}$

$f_{x}=m\gamma ^{3}a_{x}=m_{L}a_{x},\,$

$f_{y}=m\gamma a_{y}=m_{T}a_{y},\,$

$f_{z}=m\gamma a_{z}=m_{T}a_{z}.\,$