If two forces are balanced they
Imagine a person at bat during a baseball game. When a person bats the ball, the bat exerts a force on the ball and sends it into the outfield. The ball exerts an equal force on the bat, but the bat does not fly back toward the catcher because the batter is exerting another force on the bat.
Another example is jumping on a trampoline.
The boy's legs exert a force on the trampoline.
The trampoline exerts a force on the boy's legs, which causes him to accelerate upward.