00:01
We have an airplane that i'm going to draw from the side.
00:03
It kind of looks like this, and it's attached to a wire that has a length of 60 meters.
00:10
And the airplane has a mass of three quarters of a kilogram.
00:15
And there is a lift force that the plane is generating at a certain angle of 30 degrees relative to the vertical.
00:25
So that also means that this angle is going to be 30 degrees.
00:30
And we want to know a couple of things about this.
00:33
So first off, let's draw a free body diagram for the plane.
00:35
So the free body diagram, we have the weight of the plane going down this way.
00:39
We have the tension in the line going this way.
00:43
And the centripetal force goes this way because the plane is moving in a circle.
00:49
So those are all of our forces to consider.
00:53
And we want to know what's the radius of the circular path of the plane.
00:56
Well, the radius is going to be basically just this distance.
00:58
So it'll be l times the cosine of 30 degrees.
01:04
So r is l times the cosine of 30.
01:06
60 meters times the cosine of 30, which is the square root of 3 over 2.
01:14
And so this should come out to something like 51 .96 meters.
01:25
That's the radius of this little trajectory.
01:29
And then what's the magnitude of the size? centripetal acceleration.
01:32
So the centripetal acceleration is going to be mv squared over r, very simple.
01:39
And so we have three -fourths of a kilogram times the speed squared, which is 35 meters a second.
01:46
I've got neglected to mention that divided by this 51 .96 meters.
01:52
So this is our centripetal force.
01:56
I think, sorry, it asked for the centripetal acceleration, not the centripetal force.
02:00
So we just got to get rid of this m here...