Newton’s Law: Definition, Sound, Formula, Example, and Its Application

Understanding Newton’s Laws – Sinaumed’s must be familiar with Newton’s laws from the famous physicist named Sir Isaac Newton. The study of Newton’s laws has even been studied since he was in junior high school. The laws of motion of objects in the study of physics are closely related to our daily lives, which is why we can easily find applications of Newton’s Laws around our environment.

Sinaumed’s certainly needs to understand this study of physics because it is very useful in everyday life. In addition, if Sinaumed’s can master Newton’s law material, he will easily solve physics problems related to the motion of objects. The following is an explanation of Newton’s Law, starting from the meaning, sound, formula, case examples, in its application in everyday life:

Definition of Newton’s Laws

Sinaumed’s needs to know that there are 3 Newton’s Laws and each of them has a close relationship in everyday life whose force can be calculated using the formula. This theory was discovered by a famous physicist named Sir Isaac Newton. The three parts of Newton’s Laws that he discovered deal with the effect of forces on moving bodies. Then what is Newton’s law?

Newton’s law is the law of motion which is the basic law of dynamics by formulating the force for the effect of motion on certain objects. This formula became known as Newton’s Law 1, Newton’s Law 2, and Newton’s Law 3. For the services of the scientist, Newton’s term was later used as a unit of force in honor of Sir Isaac Newton for his discovery. The following is a more detailed explanation regarding the meaning of Newton’s law, 1, 2, and 3:

1. One Newton

Newton’s 1st law is to show the resultant force acting on an object with a composition equal to zero, so that an object that is initially at rest will always remain at rest. While an object initially moves in a straight line, it will forever continue to move in a straight line at a constant speed. So it can be concluded that in Newton’s Law 1 the acceleration of an object is directly proportional to the force acting on the object and inversely proportional to the mass or weight of the object itself.

The properties of objects in Newton’s 1st Law tend to maintain their original state with the same inertia or inertial properties. That is why Newton’s 1st Law is also known as the Law of Inertia. The shape of the moment of inertia in Newton’s 1st Law occurs in various forms, for example linear moments of inertia, mass moments of inertia, and polar or polar moments of inertia.

The magnitude of the stresses also differ according to the materials used, such as bending stresses and torsional stresses, so you can calculate them based on the moment of inertia. 2.Newton’s law 2

Newton’s 2nd law is related to the condition of a moving object in a state of mass of the object and the force that exists on the object is also taken into account. This shows that the acceleration of an object will be directly proportional to the net force acting on the object, while its mass will be inversely proportional to the acceleration of the object. The direction of the object’s acceleration will be the same as the direction of the net force acting on the object.

Through Newton’s Law 2 the force of an object will then become greater if it obtains a force strength that is in the same direction as the speed at which the object is moving. Conversely, if a force is applied that is opposite or opposite to the object’s force, then the speed of the force will be slower or the speed will decrease because there is a change in speed and the speed changes.

The size of the slow or fast that the moving object has, it will affect the direction of the object’s motion. This law explains that the resultant force acting on an object is not equal to zero, so the object will move at a certain speed, aka a moving object must have an acceleration.

3.Newton’s law 3

Newton’s 3rd law is the force of action and reaction shows that every action will cause a reaction. If an object exerts a force on another object, then the object that receives the force will exert a force equal to the force received from the first object. But the resulting direction will be opposite.

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Newton’s 3rd law also explains that every action will result in a reaction, or cause and effect. Giving a force as a cause will produce an effect force. These action-reaction forces then work against each other and proceed on different objects.


1. The sound of Newton’s law 1

“When the resultant force acts on an object whose composition is equal to zero, then an object that was initially at rest will continue to be at rest. Then an object that initially moves in a straight line will continue to move in a straight line at a constant speed” 2. Sounds of Newton’s 2nd Law

“The acceleration that occurs due to a change in velocity on an object will be proportional to the resultant force or the amount of force acting on the object and will be inversely proportional to the mass of the object”

3. The sound of Newton’s Law 3

“Every action will cause a reaction, so when an object gives force to another object, then the object that receives the force will give a force back that is equal in magnitude to the force received from the first object, but the direction will be opposite”


1. Newton’s Law Formula 1

The following is the formula for Newton’s Law 1 or also known as the Law of Inertia: ∑F = 0 or Resultant Force (kg m/s2)

2. Newton’s Law Formula 2

The following is the formula for Newton’s 2nd Law: F = ma,

Information: F” is the force (N), m is the mass of the object (kg), and a is the acceleration (m/s2).

3. Newton’s Law Formula 3

Newton’s 3rd law is written with the equation F action = F reaction .

Because the forms of action and reaction can take other forms, the following is the formula for Newton’s 3rd Law which is divided into three types:

  • Friction force formula: Fg = ux N

Information: Fg = friction force (N), u = friction coefficient, and N = normal force (N)

  • Weight force formula: w = mxg

Information: w = gravity (N), m = object mass (kg), and g = Earth’s gravity (m/s2)

  • Similar weight formula: s = pxg

Description: s = specific weight (N/m3), p = specific mass (kg/m3), and g = object weight (N).


As a scientific discipline, we can certainly find Newton’s law in its application in everyday life. The following are examples of Newton’s 1st, 2nd and 3rd law cases that Sinaumed’s needs to know:

Examples of Applying Newton’s Laws 1

An example of a case in the application of Newton’s 1st Law is when Sinaumed’s gets into a fast-moving car and then suddenly brakes, the passengers in the car seat will automatically be pushed forward. On the other hand, when the car is moving slowly and then suddenly accelerates suddenly, the passengers in the car seats will be pushed backwards.

Another example of Newton 1 is when Sinaumed’s places a coin on a cloth, then the cloth is pulled quickly, so the coin will remain in its original place.

This law has been proven by astronauts while in space trying to push a pencil (a pencil floats because there is no gravitational force), then the pencil moves straight at a constant speed, then stops moving after hitting the wall of the spacecraft. This happens because there is no air in outer space, so there is no frictional force that prevents the pencil from moving.

Examples of Application of Newton’s Law 2

An example of a case in the application of Newton’s 2nd Law is seen when Sinaumed’s tries to throw a stone vertically upwards. At first the stone will move at a constant speed upwards, then it will slow down and stop due to the force of gravity. The stone will descend to the earth’s surface at the speed of the rock mass plus the gravitational force that affects the acceleration of its motion.

Another example is when Sinaumed’s has a toy car, then try to pull the toy car backwards, the toy car will start moving. The stronger Sinaumed’s pulled his toy car, the faster the car would move forward. So it can be said that Newton’s 3rd law shows that the greater the force exerted on an object, the greater the acceleration of the object.

Then if Sinaumed’s tried to put a load on the toy car, the car’s motion would slow down. So it can also be said that the greater the mass of an object, the smaller the speed of the object will also affect.

Examples of Application of Newton’s Law 3

An example of a case in the application of Newton’s 3rd Law is when Sinaumed’s tries to hit a nail with a hammer, the hammer acts as an object that gives the action force and generates a force from the nail which is the reaction force from hitting through the hammer.

Another example of Law 3 is when Sinaumed’s is rowing a boat through the water. When you move the paddle backwards, the boat will move forward. Vice versa, if Sinaumed’s paddles forward, the boat will move backwards. This happens because there is an action force that Sinaumed’s exerts through the oars to give the action force, so that the boat will provide the same reaction force in the opposite direction.

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In practice, this law also involves a broader study of physics which is brought together to become a new theory to produce certain equations. The following are the elements in Newton’s laws that Sinaumed’s needs to know:

1. Gaya

Force is a form of pull or push that directs a certain object towards another object. In MKS, the unit of force is Newton ( N ), and in cgs is dyne. Force can be calculated directly using a spring balance. Meanwhile, the calculated force will be indicated by the pointer on the spring balance. The force is then divided into two, namely touch and non-touch. Touch Force is a form of force acting on objects due to touch. Examples of touch forces that we can find are muscle forces and frictional forces. While the Non-Touch Force is a force that acts on an object without touching the object, for example in the earth’s gravity and electric forces that can create a force on an object without touching it.

Following are the types of forces that Sinaumed’s needs to know in relation to Newton’s laws:

  • Item Weight (w)

Weight is the gravitational force acting on certain objects with the formula w = mg

Information m = mass of the object, g = acceleration due to gravity (g = 10 m/s2 )

  • Gaya Normal

The normal force is the contact force or touch force that acts in a direction perpendicular to a certain contact area if the two objects touch each other

  • Swipe Style (f)

Frictional force is a form of force that is in the opposite direction to the motion of a given object. That is, there are two types of frictional forces, such as kinetic frictional force and static frictional force. Kinetic friction force (fk) is the frictional force that arises when an object is moving, while static friction force (fs) is when the object is at rest.

In practice, there are frictional forces that are detrimental, such as friction between machine surfaces, the engine wears out quickly, air friction with the car, the car’s speed is hampered. Meanwhile, examples of profitable frictional forces such as those that occur in the frictional force between the footwear and the road so that people do not slip easily when walking and road friction with the surface of motorbike tires so that the tires do not slip when walking.

  • String Tension (t)

String tension is a form of tension that acts on the ends of the rope. Then the tension force at both ends of the rope is the same and the weight will be neglected.

2. Speed ​​And Speed

In the study of physics, speed and velocity have different meanings, namely speed is the speed at which a moving object has a scalar quantity or a value at a certain distance to the travel time. Meanwhile, speed is the slow change in position or displacement of an object at a certain time with a vector quantity, which has value and direction.

So it would be a big mistake if Sinaumed’s equated speed and speed in physics. In the formula equation, speed means distance divided by time, while speed is displacement divided by time. In Newton’s law, speed and velocity are all used because this law relates to moving objects that must have speed or acceleration.

3. Mass And Weight

Mass is a property of matter itself, a measure of the inertia of an object or its “amount of matter”. While weight is the gravitational force acting on a certain object to move. For example, when a rock is brought to the moon, it will remain a rock of the same size. The difference is that the weight, aka the gravitational force acting on the stone, will decrease because there is no gravity on the moon.

The relationship between mass and weight can be shown from an object with a certain mass that falls freely to the earth will only be affected by one force, namely the gravitational force of the earth or gravity. This is then called the weight W of the object. That is why F = ma gives the relationship F = W, a =g and m; to w=mg. So g=10 m/s 2 on earth, then 1 kg of object weighs 10 N on earth.

Book & Article Recommendations

Well, that’s an explanation of Newton’s Law, starting from the meaning, sound, formula, case examples, in its application in everyday life. Can Sinaumed’s understand it? Studying the exact sciences does not only require memorizing formulas but also understanding the practical working of these formulas. Sinaumed’s could start observing the application of Newton’s law around the environment to make it easier to understand the concept of the lesson.

If sinaumedia needs a reference to understand Newton’s laws and other physics lessons, you can visit sinaumedia’s book collection at . Sinaumed’s can find lessons that are in accordance with the applicable curriculum at school. Besides that, there are physics books that provide a broader perspective of scientific study, not only within the scope of teaching in schools.