# What is the force, in terms of Coulomb's constant, between two electrical charges of -225 C and -15 C that are 15 m  apart?

Feb 22, 2018

$15 k$ $N$

#### Explanation:

Electrostatic force is given by $F = \frac{k {Q}_{1} {Q}_{2}}{r} ^ 2$, where:

• $k$ = coulomb's constant ($8.99 \cdot {10}^{9} N {m}^{2} {C}^{-} 2$)
• $Q$ = charge ($C$)
• $r$ = distance between the point charges ($m$)

$F = \frac{k \left(- 225\right) \left(- 15\right)}{15} ^ 2 = \frac{k 225}{15} = 15 k$ $N$