00:01
In this problem, we have a ball hanging from the ceiling at angle beta, and it's being supported by a horizontal string.
00:09
Whenever the string is cut, the ball will swing back and forth between position a and position b.
00:16
And the problem is asking for the ratio between the tension.
00:21
This string experiences at position b with respect to position a.
00:25
And so the strategy is to apply some of the forces as equal to mass times acceleration at each point.
00:38
Now, before the horizontal string is cut, this system is in equilibrium.
00:44
The ball is just hanging and it's not moving at all.
00:47
And so we know that the vertical component of the tension here must balance the vertical component of the weight, which is all the weight.
00:56
And so applying this, some of the force is equal to zero.
01:04
And the vertical direction at point a gives the vertical component of the tension, which i label as ta is the tension on the rope at point a.
01:26
And then they get the vertical component, i multiply by cosine of beta, beta being in the angle from the vertical.
01:33
And then this must be balanced by the weight, which i'm going to denote by, if my pen stops glitching out here, w.
01:42
So w is the weight of the ball...