00:01
In this problem, we're going to talk about conservation of momentum.
00:05
So remember that the momentum of a particle is equal to the mass of the particle times its velocity.
00:11
And the total momentum of a system is conserved, as long as there are no external forces acting on the system.
00:22
So the initial momentum pi is equal to the final momentum p .f.
00:27
So the individual momentum of the particles can change, but the initial momentum, the particles, the total momentum cannot.
00:35
Okay, so now we can move on to our exercise.
00:38
So what we have is a bullet that has a mass of 15 kilograms, sorry, 15 grams, so 0 .015 kilograms, and is fired with a speed of 610 meters per second.
00:55
And the bullet sticks to a block that has a mass of 4 kilograms.
01:02
And then the block starts to move since the bullet transfers part of its momentum to the block.
01:14
Okay, then we have to consider that the block slides in the table frictionlessly, and then it falls from the table, given that the table has a height of 75 centimeters above the ground.
01:34
And with this information i go is to find how far from the table horizontally the block lands.
01:42
I say horizontally because the exercise tells us to find the point, the distance between the point where the object lands and the point directly below the edge of the table.
01:56
The first thing i'm going to do is to find what is the speed of the block.
02:00
And in order to find that, i'm going to use conservational momentum...