00:02
In this example, we're going to look at kinematics of the elastic collisions and a closed system.
00:09
Immediately from the problem, we can pick up two important facts.
00:13
The system means no forces are acting on it, which means from our impulse momentum theorem, change momentum equals zero, which means the initial velocity has to equal the final velocity of the system.
00:30
And the second thing we have is from elastic collisions.
00:32
We know that kinetic energy is conserved.
00:35
So we know initial, the difference between the initial and final kinetic energies is also going to be zero.
00:45
So we have final kinetic energy equals initial kinetic energy.
00:52
So we'll need these two equations to help us in solving this problem.
00:57
So let's get actually to the problem.
00:59
We have a helium or sorry, we have a proton.
01:06
I'll call that mass 1.
01:09
It's got mass of 1 .67 times 10 to the negative to 27 kilograms.
01:16
Moving at an initial velocity of 1 .25 times 10 to the 6 meters per second.
01:30
And this proton is traveling directly towards a helium nucleus, which i'll call mass 2...