Question

The electric force between a charged foam cup and a positively charged metal sphere is 2.12 newtons. If the charge on the cup is 2.0 × 10-6 coulombs and the charge on the metal sphere is 2.5 × 10-6 coulombs, what is the distance between the two? (k = 9.0 × 109 newton·meter2/coulombs2) 9.0 × 10-1 meters 6.4 × 10-1 meters 3.8 × 10-1 meters 2.8 × 10-1 meters 1.5 × 10-1 meters

Answer 1

Coulomb's law is given by the equation: F=$\frac{k*q1*q2}{r^{2} }$ where F is the electric force between the two particles, k is the coulomb's constant, q1 is the charge of one particle, q2 is the charge of the second particle and r is the distance between the two particles.

Rearranging the equation in finding the distance would result to:
$r = \sqrt{\frac{k*q1*q2}{F} } = \sqrt{\frac{9x10^9 * 2x10^{-6} * 2.5x10^{-6}}{2.12}}$ = 0.15 or $1.5x10^{-1}$ meters

Answer 2

0.15 meters is the answer.