What is the law of acceleration of Newton? What is its formula and use?

Newton's second law of acceleration states that the net force acting on an object equals its mass multiplied by its acceleration, expressed as F_net = ma or rearranged to a = F_net / m. This law establishes the quantitative relationship between force (cause) and acceleration (effect), revealing that acceleration is directly proportional to applied force and inversely proportional to mass. A 10 N force produces 10 m/s² acceleration on a 1 kg object, 5 m/s² on a 2 kg object, or 2 m/s² on a 5 kg object—mass is the "resistance to acceleration," also called inertia.

The formula's practical use spans all force-based motion analysis. To find acceleration, divide net force by mass: if a 1500 kg car experiences 4500 N forward thrust and 1500 N resistance (friction + air drag), F_net = 3000 N, giving a = 3000/1500 = 2 m/s². To find required force for desired acceleration, multiply: lifting a 50 kg object upward at 2 m/s² requires upward force F = 50(2 + 9.8) = 590 N because you must overcome both the desired acceleration and gravitational acceleration. To find mass, divide force by acceleration: if an unknown mass accelerates at 5 m/s² under 100 N force, m = 100/5 = 20 kg.

Newton's second law is foundational to engineering, biomechanics, and astronomy. Rocket scientists use F_net = ma to calculate thrust requirements for orbital insertion. Medical researchers analyze joint forces during movement by measuring acceleration of body segments. Structural engineers compute seismic forces on buildings from earthquake-induced ground accelerations. The law's universality—applying equally to electrons, automobiles, and galaxies—makes it one of physics's most powerful tools. Understanding that force creates acceleration (not velocity directly) prevents common misconceptions: constant velocity requires zero net force, while any net force, no matter how small, eventually produces arbitrarily large velocity changes given enough time.