You remove two socks from a hot dryer and find that they repel with forces of 0.00400 N when they’re 2.00 cm apart. If they have equal charges, how much charge does each sock have?

13.4*10⁻⁹ C = 13.4 nC

Explanation:

Assuming  we can treat both socks as point charges, the repulsive force between them, must obey Coulomb's Law, as follows:

       

where k = 9*10⁹ N*m²/C², d= 0.02 m.Replacing these values in the above equation, we can solve for  Q, as we know that both socks have equal charges, as follows:

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