Hi there, I was very excited to find the pendulum simulation, but I am trying to measure differences with different lengths, then with the same length and different masses at the end of the pendulum and I cant seem to change the mass without it disappearing off the end of my screen! I am obviously doing something wrong.  I would like to simulate a length of 30cm with masses of 100,200,300,400,500 grams, is this realistic?  I want the angle to be 45 degrees - would be grateful if you could help me to do this.  Thanks and regards Mary