00:01
So in this problem we have to find the initial speed of the bullet before it hits the block.
00:06
Once the bullet hits a block, it has fired off the table and it hits the ground.
00:10
So our final way of figuring this out is going to be using the conservation of momentum, which is going to be mvi equal to the mass of the bullet plus the mass of the block multiplied by the final speed.
00:28
Now, we don't know what the final speed is.
00:32
Let's figure that out now.
00:35
What we do know is it's falling under the effects of gravity.
00:43
So let's find out the time it takes to hit the ground.
00:47
We're going to use this equation right here.
00:50
For the change in height, equal to v0 t, plus one half a t squared.
01:00
So using the notation we have, the change in y in this case is h...