Two ropes are tied to a steel ring, and a student holds the free end of each rope. The student then pull on the ropes in a tug of war. If the forces exerted by the students are unbalanced, what happens to the ring

Two identical small charged spheres are a certain distance apart, and each one initially experiences an electrostatic force of magnitude f due to the other. with time, charge gradually leaks off of both spheres. when each of the spheres has lost half its initial charge, the magnitude of the electrostatic force will be

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

Explain why electric current cannot exist if a current doesn't have a voltage source.