Strength is a physical vector quantity that determines with what force other bodies or a field act on a given body.

Summarizing the experimental facts, Newton discovered the basic law of dynamics, formulating it in this way:

The force acting on the body is equal to the product of body mass and the acceleration reported by this force.

To calculate the strength **(F)**need a lot **(m)** multiply by acceleration **(a)**:

**F = m * a**

Unit of acceleration m / s2,

mass kg

unit of force N.

In the SI system, a force is accepted as a unit of force measurement, which imparts an acceleration of 1 m / s2 to a body weighing 1 kg; it was called Newton (N).

Based on the definition of Newton, 1 N is 1 kg.m / s2.

If the body mass m and the force F acting on it are known, we can calculate the acceleration of the body:

**a = F / m**

According to Newton’s second law, the acceleration acquired by the body will be directly proportional to the force F and inversely proportional to the mass m.

The online calculator will help you quickly and correctly calculate acceleration, strength, body weight, establish their dependence on each other.

## basic information

The first idea of strength in schoolchildren is associated with the muscular strength of a person. However, in physics, force is primarily associated with the speed and acceleration of bodies. If the object is at rest or moves without acceleration, then no forces are applied to it or the action of these forces is compensated. As soon as sufficient force is applied to the body, it begins to move.

Strength is a vector quantity, which is a measure of the mechanical effect of one object on another. The vector nature of the force demonstrates that in the first place it has a direction and a point of application. The modulus or value of a force illustrates its numerical characteristic. In the international SI system, all forces are measured in Newtons: 1 N is such a force that every second measures the speed of an object weighing 1 kg per 1 m / s.

In nature, there are many different forces from which the main ones studied in the school physics course can be distinguished:

- gravity, which affects all objects on the planet due to the gravitational field of the Earth,
- elastic force, allowing bodies to contract or stretch, which is due to the fundamental forces of molecular interaction,
- friction force, characterized by the resistance of surfaces or air to the movement of bodies,
- Archimedes force, due to which any objects always displace a certain volume when immersed in a liquid or gas.

Obviously, several different forces can act on the body at once.

## Net power

To correctly describe the movement of objects in physics, the concept of resultant or resulting force is used. The resultant is a force that, by its action, is equivalent to the influence of all the forces applied to the body. It is clear that the resultant is the vector sum of all the forces acting on the object. With multidirectional vectors, the resulting sum can be equivalent to zero. Recall Krylov’s famous fable “Swan, Cancer and Pike”: the animals applied their strength in such a way that the resultant became equal to zero. And if no forces are applied to the body, it remains at rest. Therefore, things are still there.

## Newton's Laws

The influence of forces on bodies was first described by Isaac Newton - one of the greatest physicists and mathematicians of all time. He formed three laws or axioms of mechanics, thanks to which we know the principles of the work of forces. Newton's laws were used to describe many scientific issues, for example, the motion of satellites, the influence of the moon on the ebb and flow, or the calculation of the orbits of comets. They discovered the connection between force and acceleration, which allowed scientists of that time to construct a steam engine, and later - an internal combustion engine.

In the 20th century, Albert Einstein added corrections to Newton’s laws, which related to the motion of bodies with speeds close to the speed of light. Modern scientific discoveries in the theory of relativity, quantum theory and elementary particle physics have shown that under the conditions of infinitely large and infinitesimal bodies, Newton's laws do not work. That is why modern wording is different from the laws that Sir Isaac personally formulated.

Despite the fact that all laws are related, our calculator is more dedicated to Newton's second law. Consider them.

### Newton's first law

So, if the body is not affected by forces, it either rests or moves rectilinearly and evenly. This is the historical formulation of the first axiom of mechanics, which today is considered incorrect. The fact is that Newton considered bodies in an absolutely motionless frame of reference, therefore, he spoke of absolute space and time. Today's physics takes into account the postulates of the theory of relativity, so the definition sounds somewhat different: there are such reference systems in which, in the absence of forces, physical objects are at rest. Such reference systems are called inertial.

There are also non-inertial reference systems, which themselves move with acceleration or rotate relative to inertial systems. Associated systems related to the body itself and moving with it are also possible. Naturally, in such systems classical mechanics is not applicable. Interestingly, a situation is impossible on Earth when no force acts on objects: the planet’s gravitational field creates constant gravity.

### Newton's second law

The author’s definition of this law sounds incomprehensible: the change in the momentum is proportional to the driving force and is aligned with it. The school formulation of the second axiom of mechanics is much simpler:

or force is the product of the mass of a physical object and its acceleration.

If we consider the modern formulation of the second axiom, it becomes clear that in the inertial reference frame the material point receives acceleration directly proportional to the acting forces and inversely proportional to its mass or:

It is important to clarify that the mass of a physical object does not change in time. This refinement is necessary for relativistic mechanics, in which, when speeds close to the speed of light are reached, the mass of the body begins to change.

It is this law that underlies our calculator. This simple formula is used in most physics problems from the Mechanics course. But on the agenda remained the third, last law of Newton.

### Newton's Third Law

Historically, the law sounds like "there is opposition to every action." In modern physics, such a law does not work, and in simple words the postulate sounds like this: forces arise only in pairs, and any force acting on the body comes from another body. Thus, force is always the result of the interaction of several physical objects. There are no forces that arise independently without the interaction of bodies.

Our program allows you to quickly determine the strength, acceleration or body weight, if two of the three parameters are known. To use the calculator, just enter any two values, after which the program will automatically fill in an empty field. The calculator is useful to schoolchildren and first-year students who study mechanics.

### School task

The Olympian pushes the core weighing 7.2 kg and gives it an acceleration of 18 m / s². What force does he use in such conditions? This is a simple task, for the solution of which it is enough to enter values in the corresponding cells. As a result, we obtain that to ensure such acceleration, a force of 129.6 N is required.

## power calculator

A change in the movement (push or pull) of an object as a result of its interaction with another object is called force. Strength leads to a change in the speed of the object. And also leads to acceleration or deceleration of the movement of the object. Here you can calculate either mass, or force, or acceleration from other known quantities.