Newton's Second Law Calculator
Calculate force from mass and acceleration using F = m·a, plus the object's weight under gravity.
How it works
F = m · a
Newton's second law states that the net force on an object equals its mass times its acceleration. It is the link between the forces acting on a body and how its motion changes. The same mass under gravity has a weight of m × 9.80665 N.
Worked example
A 5 kg mass accelerated at 2 m/s² needs F = 5 × 2 = 10 N of net force. Its weight on Earth is 5 × 9.80665 ≈ 49.03 N.
Frequently asked questions
Is force the same as weight?
Weight is a specific force — the pull of gravity, mass × g. The force here is whatever net force produces the acceleration you enter, which may be larger or smaller than weight.
What is a newton?
One newton (N) is the force that accelerates a 1 kg mass at 1 m/s². It is the SI unit of force.
Does this use net force?
Yes. F = m·a gives the net (resultant) force. If friction or other forces are present, they must be added in to find the applied force needed.
Related calculators
Educational estimate. Check the formula and units for your exact case.