Two balloons, one with a charge of 4.0 × 10-6 coulombs and the other with a charge of 8.2 × 10-6 coulombs, are kept 2.0 meters apart. What is the electric force between the two balloons? (k = 9.0 × 109 newton·meter2/coulombs2)
A.
4.0 × 10-2 newtons
B.
5.2 × 10-2 newtons
C.
7.3 × 10-2 newtons
D.
8.2 × 10-6 newtons

Question

Two balloons, one with a charge of 4.0 × 10-6 coulombs and the other with a charge of 8.2 × 10-6 coulombs, are kept 2.0 meters apart. What is the electric force between the two balloons? (k = 9.0 × 109 newton·meter2/coulombs2)
A. 
4.0 × 10-2 newtons
B. 
5.2 × 10-2 newtons
C. 
7.3 × 10-2 newtons
D. 
8.2 × 10-6 newtons

Vocaloid · Answer

$$F=\frac{ kq_{1}q_{2} }{ r^2 }$$
where k is Coulomb's constant (9 x 10^9 N • m^2/ C^2)
q1 is the first charge (4.0 × 10^-6 coulombs)
q2 is the second charge ( 8.2 × 10^-6 coulombs)
r is the distance between the charges (2.0m)

plug in and evaluate the electric force F