Answer:
Explanation: heat of fusion
The electrostatic force between two charges q1 and q2 is given by

where

is the Coulomb's constant

is the distance between the two charges.
In our problem, the two charges are two electrons, so their charges are equal and equal to

By substituting these values, we find the intensity of the force between the two electrons:

This is the magnitude of the force each electron exerts to the other one. The direction is given by the sign of the charges: since the two electrons have same charge, they repel each other, so the force exerted by electron 1 is toward electron 2 and viceversa.
The frequency of a wave increases when the energy increases
Answer:
A
Explanation:
A is correct as Velocity includes the + and - signs, indicating the direction followed by the magnitude which is the speed.
B is Wrong. Velocity is <em>d</em><em>i</em><em>s</em><em>p</em><em>l</em><em>a</em><em>c</em><em>e</em><em>m</em><em>e</em><em>n</em><em>t</em><em> </em>divided by time.
C Im not sure, Sorry..
D is wrong. Same explanation as B