## Knowing the Scientific Concept of Force

Forces are due to interactions. Whenever there is an interaction between objects, forces are produced due to that interaction. There has to be two or more objects so that force can come into play. There are many examples where we can see the effects of force in our real life. For instance, opening and closing a door, pushing a table, playing football or cricket.

Sir Isaac Newton developed three basic laws of motion and in 1687, he published his most important work called “The Philosophiae Naturalis Principia Mathematica”. In this work, he described the three laws of motion as well as the universal law of gravity. Newton’s laws of motion explains how objects behave when forces act upon them.

## What are the Scientific Concepts of Force?

In physics, the word force is used to express push or pull in a particular direction. Whenever you push any object, the object goes away from you. This means, a push is when something is made to move away from something. A pull is when something is drawn towards something else.

Mathematically, force is defined as the product of mass and acceleration. Mathematical formula to define force is

F = ma … … …(i)

Where, F = force,

m = mass of the object

a = acceleration of the object.

The SI unit of force is Newton (N)

## Effects of Force

The force acting on an object may change its position or shape.

Force can cause an object to move. It can stop a moving object.

Force causes change in direction of an object.

Shape of an object can be changed due to force.

These are some important effects of force which can be felt when we apply force on an object.

## When Forces are in the Same Direction

When the force is applied on an object in the same direction, it adds to one another. This means that force applied in the same direction will add up together. So, we can say that the forces are added together when two forces are acting in the same direction. Two people pushing a box together in the same direction is the best example to understand this situation.

To understand this condition, we have shown an example.

When Two Forces Act in Same Direction

Here, both forces 3N and 4N are being applied to the right. Since they are in the same direction, they will combine by addition. So, the resultant force would be 3N + 4N = 7N towards the right.

## When Forces Are in the Opposite Direction

Force applied in the opposite direction will be subtracted. Whenever force is applied on an object in the opposite direction, the net force acting on that particular object is the difference between the forces applied.

In other words, we can say that if the two forces act on the same object but in opposite directions, then the net force acting on that object is equal to the net difference between the two forces. Force could be larger or smaller.

To understand this condition, we have shown an example.

When Two Forces act in Opposite Direction

Here, we can see that both the forces 7N and 11N are in the opposite directions. These forces will combine by subtraction. So, 11N - 7N = 4N which will act in the direction of the largest force. So, this object would move towards the right.

## Different Types of Forces

There Are Two Different Types of Forces: contact force and non-contact force. Forces that are a result of the physical contact between two objects are called contact forces. Opening a door, kicking a ball and pressing a button are examples of contact force. Frictional force, normal force, spring force, tension force and muscular force are types of contact forces.

Forces which act without having physical contact between two objects are called non-contact forces. In such types of forces, physical contact is not required. Magnetic force, electrostatic force and gravitational force are types of non-contact forces.

## Solved Examples

1.Calculate the value of force for an object of $2kg$ mass which is accelerating at $5\dfrac{m}{{{s^2}}}$.

Ans: Given: acceleration $a = 5\dfrac{m}{{{s^2}}}$

Mass of an object is $m = 2kg$

Here, we will use the relation $F = ma$

$\therefore F = (2)(5) = 10N$

So, the value of force is $10N$

2.A constant force acts on an object of mass $5kg$ for a duration of $2\sec $ It increases the velocity of an object from $3\dfrac{m}{s}$ to $7\dfrac{m}{s}$. Determine the force applied.

Ans: Given: mass $m = 5kg$

Time $t = 2\sec $

Initial velocity $u = 3\dfrac{m}{s}$

Final velocity $v = 7\dfrac{m}{s}$

Here, we will use the relation $a = \dfrac{{v - u}}{t}$ to get acceleration,

So, $a = \dfrac{{7 - 3}}{2} = 2\dfrac{m}{{{s^2}}}$

Now, we will use the equation $F = ma$

Therefore, $F = (5)(2) = 10N$

Therefore, the final answer is $10N$

## Interesting Facts

Torque is the kind of force that can rotate the objects.

Gravitational forces don’t need to have contact with the objects.

Electromagnetic forces can exert force on objects which are away from them.

### Conclusion

We can conclude that in order to apply the force, it is important to know its magnitude, i.e., the amount of force as well as the direction of force. When force is applied in the opposite direction, the total force acting on an object is the net difference between the two forces. We have also discussed contact and non-contact forces along with examples of each type as well as some interesting facts about force.

## FAQs on Exploring Forces and Their Effects

**1. Explain the law of gravitation which is an example of non-contact force.**

Newton’s first law of gravitation states that every object in this universe attracts every other object with a force which is directly proportional to the product of their masses and this force is inversely proportional to the square of the distance between those objects. So, if the mass of any of the objects increases, the gravitational force will have more magnitude. Gravitational force is a long range force and it is the weakest force in nature and It is an attractive force. The free falling object is the one which moves only under the action of gravitational force of earth.

**2. Explain Newton’s first law and second law of motion in detail.**

Newton’s laws of motion plays an important role when we need to understand the behaviour of an object. Newton’s first law of motion states that an object remains in a state of rest or in uniform motion in a straight line unless it is compelled to change its state by an applied force.

Newton’s second law of motion states that the rate of change of momentum of an object is directly proportional to the applied unbalanced force and it is in the direction of force. If the rate of change of momentum increases, then the applied force also increases.

**3. What is inertia?**

The natural tendency of an object to resist any change in its state of rest or motion or direction is known as inertia. Inertia of motion, inertia of rest and inertia of direction are three types of inertia. So, inertia of an object is its property or its tendency which naturally exists in it and by virtue of which it resists any kind of change in the previously existing state of rest, motion or a particular direction in which it is moving. If an object is at rest, then it will resist movement and if an object is already in motion, then it will resist to stop.