Question

Two charged objects have a repulsive force of 1 N. If the charge of one of the objects is doubled then what is the new force

Answer 1

Taking into account the Coulomb's Law: $F_e = K\cdot \frac{Q_1\cdot Q_2}{d^2}$

If the value of Q_1 is doubled:

$F_e = K\cdot \frac{2Q_1\cdot Q_2}{d^2} = \bf 2F_e$

The new force is two times bigger too.