Newton Definition

The unit of force called the newton is named in honor of Sir Isaac Newton, who experienced force firsthand when an apple fell on his head.
Enoch Seeman, Getty Images
By
Anne Marie Helmenstine, Ph.D.
Anne Marie Helmenstine, Ph.D.
Chemistry Expert
  • Ph.D., Biomedical Sciences, University of Tennessee at Knoxville
  • B.A., Physics and Mathematics, Hastings College
Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels.
Learn about our Editorial Process
Updated on November 17, 2019

A newton is the SI unit of force. It is named in honor of Sir Isaac Newton, the English mathematician and physicist who developed laws of classical mechanics.

The symbol for newton is N. A capital letter is used because the newton is named for a person (a convention used for symbols of all units).

Formulas and Examples 

One newton is equal to the amount of force needed to accelerate a 1 kg mass 1 m/sec2. This makes the newton a derived unit because its definition is based on other units.
1 N = 1 kg·m/s2

The yellow block held by the toy's magnet exerts a downward force due to gravity and an opposing upward force.
Read More
Force Definition and Examples (Science)
By Anne Marie Helmenstine, Ph.D.

The newton comes from Newton's second law of motion, which states:

F = ma

where F is force, m is mass, and a is acceleration. Using the SI units for force, mass, and acceleration, the units of the second law become:

1 N = 1 kg⋅m/s2

A newton is not a large amount of force, so it is common to see the kilonewton unit, kN, where:

1 kN = 1000 N

Newton Examples

The gravitational force on Earth is, on average, 9.806 m/s2. In other words, a kilogram mass exerts about 9.8 newtons of force. To put that in perspective, about half of one of Isaac Newton's apples would exert 1 N of force.

The average human adult exerts about 550-800 N of force, based on an average mass ranging from 57.7 kg to 80.7 kg.

The thrust of an F100 fighter jet is approximately 130 kN. 

Format
mla apa chicago
Your Citation
Helmenstine, Anne Marie, Ph.D. "Newton Definition." ThoughtCo, Apr. 5, 2023, thoughtco.com/definition-of-newton-605400. Helmenstine, Anne Marie, Ph.D. (2023, April 5). Newton Definition. Retrieved from https://www.thoughtco.com/definition-of-newton-605400 Helmenstine, Anne Marie, Ph.D. "Newton Definition." ThoughtCo. https://www.thoughtco.com/definition-of-newton-605400 (accessed April 18, 2024).