00:01
All right, so we have a car going around a banked section of what we're approximating as a circular track.
00:09
And the banking kind of, i don't know, the sketch they provide kind of looks like this, i suppose, where the car is on this little surface going around.
00:20
And we draw a free body diagram of the car on the incline.
00:25
Let's say this is the front of the car.
00:27
So the incline is at some angle theta.
00:30
We're going to have the weight of the car going straight down.
00:34
We're going to have the frictional force acting down the ramp because the car's natural tendency as it moves is to slide up the ramp.
00:42
So the force of friction would be like the coefficient of friction times the normal force here.
00:46
The component of the weight that is along the ramp is the familiar mg -syne theta term.
00:52
And then the centripetal acceleration, the mv squared over r term, points towards the center of the circle.
00:59
And so if we look at, extend this line over, we'll see this angle right here is the same as this angle, as the angle of the incline.
01:09
I mean.
01:09
So the component of the centripetal acceleration or centripetal force that is along the plane, like down the plane, it's going to be mv squared over r times the cosine at theta...