03-17-2014

Exploring the Nature of Electrical Interactions:

The (+) and (-) charges move between conductors, that prefer the sticky side of the taps have same charge due to exchange charge between the table then the non-sticky side and sticky side will attract each other.

• 2 strips attract with different sides such as sticky to non-sticky side.
• The smaller distance between strips give stronger repel force or attract force.
• The 2nd strips tape on the 1st strip follow the same situation; therefore, top to top repel due to the same charge, bottom and bottom repel due to the same charge, and  top to bottom attract due the different charge.

Electric Force Law Video Analysis Activity

Electrical Force vs Separation Distance

Due to the free body gram, Fx and Fy should be zero due to the equilibrium. And it comes out with  F=mg*tan(data), since right triangle y(heigh) - (L^2 - d^2)^1/2, tan(data) is = d /(L^2 -d^2)^1/2. The result is mg*d/(L^2-d^2)^1/2.

The electrical force law is F = kq1q2 / r^2.

• We can calculate the charge on the balls when they have same charges that F = kq^2/r^2
• With q1=1/2q2, we can caculate q1 and q2 with F=(1/2)kq2q1/r^2.
• It is possible to determine the sign of charge on either ball. Since they repel each other, they must have same charges , but not sure is (+) or (-).
• The uncertainty is about 13.2%, the data didn't fit the curve by the external obstruct like air may exchange charge with object, gravity force affect (even it is vary small), and the resist over the rope.