Enter any two of the three variables — force (F), mass (m), and acceleration (a) — and this Newton's Second Law Calculator solves for the missing one using F = m × a. Choose what you want to calculate, pick your preferred units for each variable, and get the result with a clear breakdown.
Result
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Result in SI Units
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Formula Applied
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Force (N)
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Mass (kg)
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Acceleration (m/s²)
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Newton's second law states that the net force acting on an object equals its mass multiplied by its acceleration: F = m × a. This means that a larger force is needed to accelerate a heavier object at the same rate, and that a given force produces greater acceleration on lighter objects.
Select 'Force (F)' from the Calculate dropdown, then enter the object's mass and its acceleration along with your preferred units. The calculator multiplies mass by acceleration to give you the net force in the unit you choose.
It earned that nickname because it directly links net force to acceleration. If the net force on an object doubles, its acceleration doubles too (assuming constant mass). This proportional relationship between force and acceleration is the law's defining characteristic.
It depends on the car's mass. Using F = m × a, a 1,000 kg car accelerating at 5 m/s² requires a net force of 5,000 N (5 kN). In practice, the engine must also overcome friction and drag, so the actual driving force is higher.
In SI units, force is measured in Newtons (N), mass in kilograms (kg), and acceleration in metres per second squared (m/s²). One Newton equals the force required to accelerate a 1 kg object at 1 m/s². Other common unit systems include dynes (CGS) and pound-force (imperial).
The first law (inertia) states an object stays at rest or in uniform motion unless acted on by a net force. The second law (F = ma) describes how force, mass, and acceleration relate. The third law states that for every action there is an equal and opposite reaction.
Yes. The equation F = ma rearranges to m = F / a (to find mass) and a = F / m (to find acceleration). Use the 'Calculate' dropdown in this tool to choose which variable you want to solve for, then provide the other two known values.
Isaac Newton formulated his three laws of motion in his landmark work 'Philosophiæ Naturalis Principia Mathematica', published in 1687. The second law, relating force, mass, and acceleration, has since become one of the most fundamental principles in classical mechanics.