# Homework Help: Pendulums and damping.

1. Nov 17, 2004

### Brewer

I have been given a question about damping that will form part of my A-level coursework, and I wondered if any of you could think of a decent way to go about it.

The brief is to investigate how the amplitude of a compound pendulum decreases with the degree of damping.

Metre rule (to act as a pendulum)
Card (to be placed on the rule to damp the oscilations)
various measuring equipment

The initial thought that I had was to attach a piece of chalk to the pendulum, and touch it against a piece of paper/card to draw the oscilations so that I could accurately measure the amplitude of the oscilations and see the effect that damping had on the system as the area of the card was increased. However I soon realised that this would increase the friction in my system, therefore introducing more variables into my system (i.e it could be the friction of this and not the damping that reduces the amplitude of the oscilations).

My next idea was to see how to time differed for a set number of oscilations (10 for example). This is an idea that I may follow up and do some work with in my preliminary work.

Another idea on the "good" list would be to measure the amplitude of the oscilations and see how they differ. This is another possible idea, but again needs to be investigated in preliminary work. However I feel that it may be too difficult to accurately measure the amplitude, as its obviously not stationary when you need to measure it (well it is technically - just not for long!).

So could any of you give me some more ideas of how to go about this investigation, or suggest a relationship for this. I know it will involve a variable to the power of something, but I am unaware of where to start looking for this.

Thanks in advance for any help.