energy, Erest = mc^2 , and its kinetic energy.If we plot the kinetic energy of a particle of mass m as a function of its speed v, we
get the following graph:
Notice that as v approaches c, the object’s kinetic energy approaches infinity. This
shows why it’s impossible for a massive particle to move at the speed of light (or
at any speed greater than c). The force accelerating a particle would have to do
more and more work to increase the particle’s kinetic energy, and it would take an
infinite amount of work to push a particle to the speed of light (where its kinetic
energy would be infinite). The universe has a speed limit: Light moves at speed c,
and everything else moves at a speed less than c.