Force Calculator (F=ma)
Calculate force, mass, or acceleration using Newton's second law
Calculator
F = m × a = 10 kg × 10 m/s² = 100.0000 N
W = m × g (mass × 9.81 m/s²)
Newton's Second Law
- F = m × a (Force = Mass × Acceleration)
- m = F / a (Mass = Force / Acceleration)
- a = F / m (Acceleration = Force / Mass)
- 1 Newton = 1 kg × m/s²
- Weight W = m × g (g = 9.81 m/s² on Earth)
How to Use
Calculate force, mass, or acceleration using Newton's Second Law
Select variable
Choose to calculate force, mass, or acceleration
Input values
Enter mass (kg) and acceleration (m/s squared) or other known values
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See the calculated result with weight calculation bonus
Newton's Second Law
F = m x a
Force equals Mass times Acceleration.
Frequently Asked Questions
Newton's Second Law states that Force equals Mass times Acceleration (F = ma). This fundamental physics equation explains that greater force is needed to accelerate heavier objects, and the same force produces less acceleration on heavier objects.
The SI unit for force is the Newton (N), defined as kg times m/s squared. One Newton is the force needed to accelerate 1 kilogram at 1 m/s squared. Other units include pound-force (lbf, approximately 4.45 N), dyne (0.00001 N), and kilogram-force (kgf, approximately 9.81 N).
Weight is the gravitational force on your mass: W = m x g, where g = 9.81 m/s squared. A 70 kg person weighs 70 x 9.81 = 686.7 N on Earth. On the Moon (g = 1.62 m/s squared), the same person weighs only 113.4 N.
Mass is the amount of matter (measured in kg), constant everywhere. Weight is the gravitational force on that mass (measured in N), which varies with gravity. A 70 kg mass weighs 687 N on Earth but only 113 N on the Moon.