00:01
We've got a plane diving.
00:04
So i'm going to draw the vertical.
00:08
And then this is the speed of the plane.
00:11
And the angle here is 53 degrees.
00:15
So i'm going to rate theta 1.
00:17
Theta 1 is 53 degrees.
00:25
Okay.
00:27
Releases it at an altitude of 730 meters.
00:33
Okay.
00:33
So here we go.
00:36
It's going to release a projectile at y -sub -0 is 730 meters.
00:46
So the projectile is going to go, i don't know, maybe like that.
00:55
It hits the ground five seconds after being released.
01:05
What's the speed of the aircraft? okay.
01:10
Well, v.
01:13
Sub x times t so let me think here the distance that the projectile moves so v equals distance over time so the distance is going to be v t is going to be vx which would be v sine theta 1 times t okay, but we don't know x and we don't know v.
02:12
So let's try the other direction.
02:19
Y final, which is zero, is going to equal y initial, minus vy initial, which would be v, cosine theta 1 times t minus one half g t squared so i can figure out v from this one just rearranging it's going to equal y0 minus one half g t squared over cosine of theta 1t.
03:17
I'm going to write that as t t cosine theta 1.
03:22
So, putting that into a calculator, i have y -sub -0 is 730.
03:37
T is 5.
03:40
Theta is 53.
03:45
So, v, this is v, no, that's just v.
03:55
Equals y sub 0 minus 1 half g t squared over t cosine theta.
04:12
That's 202 meters per second...