week 4 day 2

We started electric forces.

We did some tape experiment. Maybe it was a wet day, it didn't go well.

But at least, the tapes attract each other.

Then we looked at a metal ball repel another metal ball that hangs under a string. We calculated the force on the repeled ball in terms of mass, displacement and length of the string.

We inserted points and got this graph of the force/seperation distance.

We then looked into electrical force between two point particles that have charge.

Then we calculated electrical force in two dimension.

this is a electric generator. charge went to the paper strips. when they have same charge, they repel each other.

Then we did calculation of electric force based on the formula Fe=Kq1q2/r^2

comparing to gravitation formula Fg=Gm1m2/r^2

Then we noticed gravitation force is very small.