The Newton is the SI measurement unit for force, named after Sir Isaac Newton. Learn about what is measured in a Newton and how it converts to other measurements of force.
Updated: 03/27/2022
Measure and Understand the Newton Unit of Force
What is a Newton Unit?
Force is an interesting phenomenon known as the Newton definition that measures the rate of acceleration of an object based on its mass related to speed of travel per second squared. The international Newton unit of measurement was named after its' discoverer, Sir Isaac Newton. However, many people do not completely understand what is measured in Newton's, so let's take a closer look.
What is a Newton?
- It is the System International (SI) unit of measurement for Force. There are also other units of measurement for force that will be explored later in this lesson.
- To understand this, it is important to define mass, acceleration, and speed.
- Mass is often confused with weight, but these are different concepts. Weight is mass when gravity is exerted (pushed down) upon it. The mass of an object is how much matter is present. Mass does not change in an object regardless of the impact of gravity. Thus, the mass of a specific item is the same on Earth and the Moon, but the weight of the same object will be different because gravity is different on Earth vs. on the Moon.
- Acceleration has both direction and magnitude, known as vector quantities. This measures the change in velocity concerning time. This is measured by calculating the change in velocity/change in time.
- Speed, on the other hand, only takes into account distance traveled over time. It does not account for magnitude. Speed = distance/time (s=d/t).
Now, let's take a look at the Newton measurement. The Newton unit (N) considers all of the above measurements. Thus, a single newton is the amount of force required to accelerate 1 kilogram of mass 1 meter per second squared in a specific vector of direction.
The formula for force is written as: 1N = 1kg (m/s/s).
Who was Sir Isaac Newton?
Sir Isaac Newton lived from 1643 - 1727 (84 years). He was a philosopher, scientist, and mathematician who greatly impacted the field of physics. For example, after watching an apple fall from a tree, he began thinking about what caused it and if it always happened at the same rate. This was the experience that birthed his discovery of the law of gravity. He also discovered the three laws of motion.
- Inertia: An object at rest remains at rest, while an object in motion remains unless impacted by another force.
- Force: This equals the mass of an object times the acceleration.
- Action & Reaction: This law states that for every action, there is an equal and opposite reaction.
Force of Gravity
Anything with mass has a natural attraction to other things with mass. The force of attraction between the two masses is known as Gravity, a law relevant everywhere in the universe, from the smallest of particles (atoms) to the largest (such as planets, stars, and moons). When witnessing the apple falling, Sir Isaac Newton started pondering this phenomenon and figured it must directly impact all things on Earth. Otherwise, it would not be possible for things to remain on Earth at the speed and revolution of which it is spinning. As he continued investigating gravity, he realized that it exists between all things with mass.
Newton explained the Law of Gravity with a mathematical formula after watching how objects are attracted to each another. After many observations and experiments, it was discovered that there is a proportional relationship between two masses (m1 and m2), which is inversely proportional to the distance (r) squared between each of the centers of mass. The mathematical formula for gravity on Earth is based on the Gravitational Constant of 6.6726 x 10^-11 m^3 kg^-1 s^-2 since Earth is much larger than any other object.
- F = G (gravitational constant) * M1 (mass of object 1) * M2 (mass of object 2) /r^2 (the distance between the two objects)
The formula for Gravity for things on Earth is written as F = G * M1 /(distance to the center of Earth)^2.
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.
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When this formula is put into action, it is discovered that objects fall to Earth at a rate of 9.8 meters per second squared. Thus, the meters per second doubles for every second as an object falls to Earth. So, after two seconds, the item is traveling at a rate of 19.6 meters per second, and so on.
Unit of Force Measurements
What unit is force measured in? The SI unit of force is the Newton. However, other measurements of force are used throughout the world, including the poundal, kilopond, dyne, and pound-force. The poundal (pdl) is a measurement used to move 1 pound accelerating at 1 foot per second squared. The kilopond (kp), also known as kilogram-force (kgf/kgF), is equivalent to a kilogram of weight under standard gravity on Earth. The pound-force (lbf) is equivalent to one pound of weight under standard gravity on Earth. The dyne, also known as centimeter-gram-second (CSG), is equivalent to moving 1 gram of mass the distance of 1 centimeter per second squared.
Newton Measurement Conversion
Since poundals, kiloponds, dynes, and pound-force are not the SI measurement of force, it is necessary to understand the conversion rates.
- 1 Newton is equivalent to 7.2330 poundals
- 1 Newton is equivalent to 0.10197 kilopond
- 1 Newton is equivalent to 100,000 dynes
- 1 Newton is equivalent to 0.22481 pound-force
Newton Measurement Conversion Examples
Unit of force conversions become necessary when something is measured in a non-SI force and must be converted to Newtons. Here are some examples.
- Poundal (pdl) = Newton (N) x 7.2330; so how many Poundals are 5 Newtons? 5 x 7.2330 = 36.165 pdl
- Kilopond (kp) = Newton (N) x 0.10197; so how many Kiloponds are 10 Newtons? 10 x 0.10197 = 1.0197 kp
- Dyne (CSG) = Newton (N) x 100,000; so how many Dynes are 6 Newtons? 6 x 100,000 = 600,000 CSG
- Pound-force (lbf) = Newton (N) x 0.22481; so how much pound-force is 8 Newtons? 8 x 0.22481 = 1.79848 lbf
Lesson Summary
The Newton is the SI measurement for force. It was discovered by Sir Isaac Newton, a magnificent scientist and mathematician who discovered many laws in physics. Force takes into account acceleration, mass, and speed. One newton is what is required to accelerate 1 kilogram of mass 1 meter per second squared in a specific vector of direction. Gravity is another phenomenon discovered by Sir Isaac Newton. This is the proportional relationship between two masses (m1 and m2), which is inversely proportional to the distance (r) squared between the center's masses. On Earth, gravity is constant due to the size of the Earth and the distance to its center, which is 9.8 meters per second squared. Other non-SI force units of measurement include the poundal, kilopond, dyne, and pound-force.
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.
- After one second, an object will fall at 9.8 meters per second.
- After two seconds, the object will be traveling at 19.6 meters per second.
- After three seconds, the object will be traveling at 29.4 meters per second.
- And so on.
Conversions to Other Units
While the newton is the metric unit of force, other measurement systems have their own units to measure force with. Here are some conversions between the newton and their units.
Newtons to dynes:
1 N = 10^5 dyn = 100,000 dyn
Newtons to kiloponds:
1 N = 0.10197 kilopond
Newtons to pound-force:
1 N = 0.22481 pound-force
Newtons to poundals:
1 N = 7.2330 poundal
Lesson Summary
A newton is a unit of measurement for force. The units for a newton are kilogram meter per second squared. The newton is named after Sir Isaac Newton, whose theories describe the laws of motion and have been influential on modern physics for the last 400 years.
A Newton
 |
| The Newton |
|---|
| *Named after Sir Isaac Newton * International unit of measure for force *1 kg meter per second squared |
Learning Outcomes
When you are done, you should be able to:
- Explain what a newton is
- Summarize the significance of Sir Isaac Newton
- Recall the units for a newton
- Understand how to determine the force of gravity exerted by Earth
- State some conversions for newtons
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Video Transcript
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.
- After one second, an object will fall at 9.8 meters per second.
- After two seconds, the object will be traveling at 19.6 meters per second.
- After three seconds, the object will be traveling at 29.4 meters per second.
- And so on.
Conversions to Other Units
While the newton is the metric unit of force, other measurement systems have their own units to measure force with. Here are some conversions between the newton and their units.
Newtons to dynes:
1 N = 10^5 dyn = 100,000 dyn
Newtons to kiloponds:
1 N = 0.10197 kilopond
Newtons to pound-force:
1 N = 0.22481 pound-force
Newtons to poundals:
1 N = 7.2330 poundal
Lesson Summary
A newton is a unit of measurement for force. The units for a newton are kilogram meter per second squared. The newton is named after Sir Isaac Newton, whose theories describe the laws of motion and have been influential on modern physics for the last 400 years.
A Newton
|
| The Newton |
|---|
| *Named after Sir Isaac Newton * International unit of measure for force *1 kg meter per second squared |
Learning Outcomes
When you are done, you should be able to:
- Explain what a newton is
- Summarize the significance of Sir Isaac Newton
- Recall the units for a newton
- Understand how to determine the force of gravity exerted by Earth
- State some conversions for newtons
To unlock this lesson you must be a Study.com Member.
Create your account
- Activities
- FAQs
Two Equations for Force
In the lesson, the equation for the force of gravity was introduced. The units are kg-m per second squared. Newton's second law relates force, mass, and acceleration and is:
F = ma
The unit of mass in the SI system is the kilogram. Acceleration has units of meters per second squared. Therefore, the units of force are the same in both equations. The lesson showed you that the force of attraction of gravity on planet Earth is 9.8 m per second squared. Let's look at a couple of situations where these equations are used.
Universal Law of Gravitation Problem
Find the gravitational force on Earth's Moon and compare it with Earth's gravity.
Looking at the equation given in the lesson, it appears that we need the distance between the center of the Moon and its surface (its radius), and also the mass of the Moon to calculate this value.
Using the Internet, we find that the radius of the Moon is 1737 km and its mass is 7.34 x 10^22. Putting these values into the equation, the result is 1.62 kg-m/second squared.
Comparing this to the gravity of the Earth, we find that the gravity on the Moon is about 1/6 of that.
Newton's Second Law
This equation comes in handy in a variety of situations. In the case of free fall, where the only force on an object is gravity, the equation becomes:
F = mg, where g is the acceleration of gravity
This force is the force of the object on the Earth and is the weight of the object.
What is the weight of an apple if its mass is 100 grams?
Convert 100 grams to 0.100 kg and multiply by the force of gravity (0.98 N). An apple of this mass has a weight of about 1 N.
Check on learning
Perform the following force calculations. Find any pertinent information using the Internet or other sources.
1. Find the force of gravity of the two planets closer to the Sun than Earth.
2. What are the weights (on Earth) of the following objects: a 100 kg man, a 25 kg dog, an elephant with a mass of 6,000 kg.
Answers
1. g on Mercury = 3.70 m/seconds squared, g on Venus = 8.87 m/seconds squared
2. 980 N, 245 N, 58,800 N
What is a newton in simple terms?
In simple terms, a Newton is the System International (SI) unit used to measure force. Force is measured using acceleration, mass, and speed.
How much is 1 newton?
A Newton is the SI measurement of force. One Newton is the force necessary to accelerate 1 kilogram of mass 1 meter per second squared.
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