posted by Daniel on .
Five styrofoam balls are suspended from insulating threads.Several experiments are performed on the balls and the followingobservations are made:
I. Ball A attracts B and repels C
II. Ball D attracts B and has no effect on E
III. A negatively charged rod attracts both A and E
What are the charges, if any, on eachball?
A B C D E
A) + - + 0 +
B) + - + + 0
C) + - + + 0
D) - + - 0 0
E) + 0 - + 0
The answer is D.
I understand that A and C have to have the same signs and that B is the opposite sign of A and C. What I don't understand is why D and E are 0.
remove the brackets to see the diagram sorry