00:01
All right, so let's say we have a conical pendulum where a ball is moving around a circle.
00:06
And the rope that supports this has a length of l.
00:14
And it has a circular cross -section of 2 millimeters.
00:19
So we'll call that a, i guess, or cross -section width of 2 millimeters.
00:27
So we'll call that a anyway.
00:28
Anyway, l is equal to 2 .2 meters and it's under tension.
00:36
The mass of the ball being whirled around is 3 kilograms and the angle theta is 17 degrees.
00:45
So we want to know, let's balance the vertical forces on the ball.
00:50
So basically we'll have the tension in the cable times the sign of this angle should be equal to just the weight of the ball.
00:56
And then part b, the horizontal component should just be equal to mv squared over the radius of the circle, which we can write r, you can see, is l cosine, theta, so we'll write it this way.
01:17
And then part c, we want to calculate the radius of the circle the ball describes.
01:21
So r, like i said, l cosine theta...