What is a Newton? – Units & Explanation

Isaac Newton

In physics, a newton (N) is the metric unit of force. It was named after Sir Isaac Newton.

Sir Isaac Newton was a physicist, mathematician, and philosopher. Newton’s theory of classical mechanics was one of the most important and influential achievements in science. He advanced the works of Galileo, Kepler, and Huygens and formulated his theories into three fundamental laws of motion. Newton’s laws of motion are the basis of classical mechanics.

Definition

A newton (N) is the international unit of measure for force. One newton is equal to 1 kilogram meter per second squared.

In plain English, 1 newton of force is the force required to accelerate an object with a mass of 1 kilogram 1 meter per second per second.

Gravity

We can determine the force of gravity exerted by Earth by using this equation:

Where:

F = Force
G = Gravitational constant = 6.67 x 10^-11 m^2 / (kg * s^2)
M1 = mass of the first object
M2 = mass of the second object
r = distance between the two objects

When we are talking about objects on Earth, and the fact that the Earth is so much larger than any object it is compared to, we can essentially ignore the mass of the second object M2.

We can simplify the gravity equation for Earth like this:

F = G * M1 / (distance to the center of Earth)^2

Therefore, whenever we talk about gravity on Earth, we can say that the force of gravity on any object on Earth will be 9.8 meters per second squared. This means any object falling to Earth will fall at a rate of 9.8 meters per second squared.