The electrostatic force between two charges q1 and q2 is given by

where

is the Coulomb's constant and r is the distance between the two charges.
If we use F=19.2 N and q1=q2=-3.0 C, we can find the value of r, the distance between the two charges by re-arranging the previous formula:
If the two waves have the SAME FREQUENCY and are exactly
out of phase (180° apart), then the resultant wave will have the
same frequency and an amplitude of 1 unit.
If the two waves do not have the SAME FREQUENCY, then their
relative phase is meaningless.
<span>The
thermal energy found in a piece of coal is lesser than in the thermal energy in
a newly opened coal mine. The newly opened coal mine requires a greater thermal
energy to really open it due to its solid structure. Whereas in a piece of
coal, it only requires a lesser amount of thermal energy to extract it.</span>