balls : instructions below

to start: click "go"
to create a ball: click on a free area (click and drag for initial speed)
to move a ball: click on the ball and drag (click "stop" if the ball is too fast)
to remove a ball: click on the ball and drag it out of the ball box

try this:

1)

2)

sim:
in numbers "e" or "E" means " *10^ ". for example 5e2 = 500. 1 pixel = 1 meter. the magnetic field vector is vertical to the screen. the simulation is runing in realtime: if there are too many balls or the speed of a ball is too high, the simulation becomes inaccurate. with many(most) combinations of parameters the balls become very fast and behave unrealistic.

Šadam