00:01
All right, so let's say we have a plane.
00:02
It kind of looks like this.
00:04
And it's flying at a speed of 240 kilometers per hour.
00:12
And it wants to drop supplies onto a ridge that is 235 meters below them.
00:20
And they want to know how far in advance must the goods be dropped.
00:28
So basically, like, how long does it take to fall this distance? so the time, let's call it part a.
00:35
The time it takes delta t is just going to be the square root of twice the height over g.
00:42
So the square root of 470 meters over 9 .8 meters per second squared.
00:53
Let me take the square root.
00:54
So this is about 6 .93 seconds.
01:00
And so part b, suppose instead that the plane releases the supplies at a horizontal distance of 425 meters in advance, what vertical velocity up or down should the supplies be given so that they arrive at the position.
01:16
In part b, i forgot to mention.
01:18
So the distance delta x is just going to be 66 .7 meters a second.
01:24
That's the speed of the plane times 6 .93 seconds.
01:29
So 66 .7 times 6 .93 is about 462 .2 meters.
01:40
So part b, we want delta x to be 425 meters, and this should be equal to the velocity of the plane.
01:54
So we'll say 66 .7 meters a second times the fall time.
01:59
And so the fall time might be a little bit different...