Question

A piece of tape is pulled from a spool and lowered toward a 130-mg scrap of paper. Only when the tape comes within 8.0 mm is the electric force magnitude great enough to overcome the gravitational force exerted by Earth on the scrap and lift it.

Determine the magnitude and direction of the electric force exerted by the tape on the paper at this distance.

Express your answer to two significant digits and include the appropriate units. Enter positive value if the force is directed upward and negative value if the force is directed downward.

Answer 1

Elechic field 15oXo

So, electric force F_E = 12.75 * 10^-4N, in upward direction