In this paper, the effect of resistances on applied force has been studied practically. As per the study, the existing Newton’s equation (F=ma) calculates only net force and does not count the effect of resistances. It has been observed that in every action some part of the applied force is required to overcome the effect of resistances (friction, air resistances, etc.); and when applied force exceeds that amount only then a stationary body accelerate. Hence a mathematical expression (F=ma+r) has been provided by including a factor describing above said resistances.