Sir Isaac Newton, in his laws of motion, made statements about the effect of balanced and unbalanced forces.
Newton's first law is concerned with balanced forces. The first law states that if a body is at rest and the forces acting on it are balanced then the body will remain at rest. However if the body is moving and the forces acting are balanced then the body will keep moving at constant speed in a straight line.
Newton's second law is concerned with unbalanced forces. Unbalanced forces produce acceleration. The bigger the unbalanced force the bigger the acceleration. This law is usually written as an equation . You'll find more information on this law later in this section.