Forces and Newton’s Laws

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Physics Newtonian Mechanics Forces and Newton’s Laws

	Newton's Second Law:
	Newton’s second law of motion states that the force exerted on an object is given as the rate of change of momentum of it. The force is then given by, The quantity is called momentum, m is the mass of the object and t is the time. Since, mass is a scalar quantity and the rate of change of velocity is the acceleration of the object, the force exerted on the object can be expressed as: Thus, the expression of force is nothing but the product of mass and acceleration of the object. Hence, it provides the quantitative definition of force. Newton's third Law Newton’s third law of motion states that “for every action there is an equal and opposite reaction. If there are two objects interacting with each other so that object 1 exerts a force F₁₂ on the object 2 and the object 2 exerts a force F₂₁ on object 1 then the relationship between these two forces would be: F₁₂ = -F₂₁, since the forces are in opposite directions and of equal magnitude. Thus, F₁₂ and F₂₁ are action and reactions.