00:01
In this problem, we're going to talk about relativistic energy.
00:03
And what we need to remember is that the rest energy of a particle is equal to its mass times the speed of light squared.
00:11
The total energy is equal to mc squared times gamma, and the kinetic energy is equal to mc squared times gamma minus 1.
00:24
And gamma, we need to remember, is 1 over the square root of 1 minus v squared over c squared, where v is just the speed of the particle.
00:35
And what we have in our problem is a particle that has a mass of one gram, that's 10 to the minus 3 kilograms, and a speed of 0 .8 times the speed of life.
00:49
And i'm going to find the kinetic energy, the total energy, and the rest energy of this particle.
00:56
Let's start by the kinetic energy.
00:58
That's m, c squared, down minus 1, m is 10 to minus 3 kilograms...