The Physics of the Universe
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F = ma Calculator

Apply Newton's second law F = m × a — enter mass and acceleration to find force, or solve for mass or acceleration. Choose your own units for each value.

 

Formula

$$ F = m\,a \qquad m = \frac{F}{a} \qquad a = \frac{F}{m} $$

Worked example

A 20 kg mass accelerating at 5 m/s² needs \( F = (20)(5) = 100\ \text{N} \) of force.

How it works

Newton's second law states that the force on an object equals its mass times its acceleration: F = m a. It is the foundation of classical mechanics, linking the cause (force) to the effect (acceleration).

Enter any two of force, mass and acceleration and the calculator finds the third. Force is in newtons (N), where 1 N accelerates 1 kg at 1 m/s².

Frequently asked questions

What is Newton's second law?

It states that force equals mass times acceleration, F = ma. The acceleration of an object is proportional to the net force and inversely proportional to its mass.

How do you calculate acceleration from force and mass?

Rearrange to a = F/m. Set 'Solve for' to Acceleration, enter the force and mass, and the calculator returns the acceleration.

What is a newton?

One newton (N) is the force that accelerates a 1 kg mass at 1 m/s². It equals 1 kg·m/s².

What is the difference between mass and weight?

Mass is the amount of matter (kg) and is constant. Weight is the gravitational force on that mass, W = mg, and changes with gravity — you weigh less on the Moon.

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