For those at the back of the class -
Still photos of the bucket in a cruise are NOT what you should be looking at.
Find some youtube material of when the bucket is emptying and that will change your outlook.
As it goes from bag of water to windsock there is an overshoot of the stable windsock attitude towards the tail. The overshoot magnitude is tied to speed.
And with respect to line length - look up what makes a pendulum period longer or shorter - good starting point.