Answer
Equilibrium is the state where the rate of the forward and the reverse reaction are the same.
Two examples of dynamic equilibrium: A chemical reaction at equilibrium, and an object at constant speed, where, according to Newton's Law, the sum of all forces is equal to zero.
Work Step by Step
You can find this definition of equilibrium in the first section of this chapter of the book, or in any dictionary with a chemistry definition for equilibrium.