Formula
The SI statement of Newton's second law, with grams converted to kilograms first:
newtons = kilograms × m/s²
The newton is defined in the SI Brochure. A separate weight page is not published: weight is this same product with the local gravitational acceleration typed in. Results use up to six significant figures, and very large or very small numbers use scientific notation.
Assumptions
- Acceleration stays constant while the force is applied.
- Mass is the inertial mass, not a weight in pounds.
- The result is the magnitude. Direction is not shown.
Worked example
A 10 kg mass at 2 m/s² needs 20 N.
Input definitions
- Mass
- Kilograms or grams of the object.
- Acceleration
- How quickly the velocity changes, in meters per second squared. Zero is allowed.
Limitations
This is a classroom magnitude. It does not model friction, a changing mass, or a structure's safe load.
Questions
Can I find weight?
Type the gravitational acceleration, about 9.81 m/s² near Earth's surface. The formula is the same product.
Why is the unit a newton?
The SI unit of force is the newton, equal to one kilogram meter per second squared.