00:01
All right, so let's say we have a ball with a mass of, called m1, 1 .5 kilograms, and it swings down from a height difference of three meters with an initial speed of five meters a second and strikes another ball that has a mass of 4 .6 kilograms.
00:25
And so we want to know what is the speed of the first ball just before context.
00:29
So what we'll have is 1 half mv final squared minus v initial squared.
00:36
That's equal to the gain or the loss of potential energy with a negative sign.
00:42
So it's really just mgh.
00:44
So the masses cancel.
00:45
We'll see that our final speed is going to be our initial speed squared plus 2gh.
00:53
So if you do that, 25 plus 19 .6 times 3.
00:57
And then we take the square root should be 9 .15.
01:01
Meters a second.
01:03
And then part b, we want to assume that there's an elastic collision between the two.
01:09
And so we want to find out what is the velocity of both balls after the collision.
01:14
And so what we'll have is v1 prime.
01:17
You know, if you look at ordinary elastic collisions, this will be m1 minus m2 over m1 plus m2 times v1.
01:27
Since our other ball is stationary, we're not going to have any other numbers here.
01:30
And so this comes out to negative 0 .1 meters a second approximately and then v2 prime this is just going to be um 2 times m1 over m1 plus m2 times v1 and so that's about 9 .05 meters a second um and so then from there let's see am i missing anything else i don't think so so um now we want to find out how high does each ball swing after the collision...