Common Forces in Mechanics
When we study laws of motion, we deal a lot with common forces in mechanics. So, what are the different types of common forces of mechanics? A force is the change of state of an object due to external surroundings. Due to forces, an object will either be in a state of motion or will be resting. For example, consider a football placed on the ground motionless. To move the ball in any direction, you will have to apply some forces on the ball. In this case, you are applying a force to the ball with the help of your legs. Eventually, the ball will move in the intended direction. The common forces in mechanics can be classified into two main groups, that is contact forces and non-contact forces. In this article, we will look at different types of force class 8, and the electrostatic force definition for class 8.
Contact Forces
As the name suggests, we experience contact forces only when the two objects come in contact. Some of the common examples of contact forces are tensional forces, air resistance forces, and frictional forces. In contact forces, the energy is transferred from one object to another. Sometimes you can also notice contact forces when an object is immersed in liquid. We will now look at different types of contact forces.
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Spring Force
We all have seen and used spring in our lives. You must have noticed that it shrinks down when you apply force on one side of the spring. As soon as you release the force, the spring jumps back to its original state. Spring force is defined as the force that acts opposite to the displacement of the object.
Applied Force
The applied force is one of the most common types of force class 8. You can witness this force every day. The applied force is the force that we apply on objects using our hands or legs, or by any other object. When you push your chair, you are applying some force to move it in a specific direction.
Air Resistance Force
Air resistance force is the resistance that is naturally present in the air. When you throw an object up in the air, you will notice the object starting to de-accelerate, and this is due to air resistance and gravitational force.
Normal Force
The normal force is the force that is acting on a body that is at a state of rest. When an object rests on another object, it will experience a normal force, that is perpendicular to the surface. This happens to support the weight of the object when placed on a surface.
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Tension Force
When we talk about tension force, we refer to the pull force that a rope or string experiences when it is pulled by an object.
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Frictional Force
The frictional force is the force that acts on a moving object. A moving object will be in continuous contact with the surface. The surface exerts a force in the opposite direction of the moving object, which is called frictional force. Everyone experiences a frictional force when walking.
Non-Contact Forces
These forces happen when two objects are placed at some distance. The two objects never come in close contact with each other. The most common non-contact force is gravity. The object never comes in contact with it, yet it is always present and acting upon the object. Some of the essential con-contact forces are explained below.
Electromagnetic Force
The electromagnetic force comprises the magnetic and electric forces between atoms and molecules. The most common example of the electromagnetic force is a magnet. In a magnet, like poles repel and unlike poles attract towards each other.
Gravitational Force
When two objects have mass or matter, there exists gravitational force between them. Gravitational force can be considered an attractive force because it keeps pulling the object to it, for example, the gravity of the earth.
Nuclear Force
There is a strong bond between two or more nuclei or protons; this bond is called nuclear force. The nuclear force is also considered as an attractive force.
Electrostatic Force
Electrostatic force definition for class 8 can be stated as the force between two electrically charged particles. They can either be a repulsive or attractive force. Like charges will repel each other and unlike charges will attract each other.
Force is defined as the push or pull acting on an object. It means that when we push or pull a body, we apply force. Students of class 8 will study different types of forces that exist in nature. Different types of forces exist and students must know the different types of forces and their differences. In this part, we will discuss the different types of forces. The two main categories of force include contact and non-contact forces.
The most important differences between contact and non-contact forces are given here:
Difference Between Contact and Non-Contact Forces
Effects of a Force
When a force is applied on an object, it can produce different effects. The difference effects of a force produced on an object are given here:
When a force is applied on an object and an object is in motion, the force can stop the object from moving.
When a force is applied on an object and an object is at rest, the force can make the object move.
When a force is applied on an object it can slow down its motion
When a force is applied, the force can also increase the speed of an object
The applied force on an object can also change the direction of motion of an object
The force can also change the shape and size of an object
FAQs on Types of Force for Class 8
1. Explain the line of action of a force.
The line of action of the force can be defined as the line on which the force is acting on an object. The point where the force is acting is called the point of application of the force.
2. Explain balanced and unbalanced forces.
When the net force acting on an object is zero, the forces acting on an object are said to be balanced. When the net force acting on an object is not equal to zero, the forces are said to be unbalanced. The unbalanced force can increase the speed of the body which means that the force acting on an object can either change the magnitude or direction of velocity. For example, when different forces are acting on an object and the object does not move, it means that the net force on an object is zero.
3. Calculate the force required to accelerate a body of mass 500kg at 5 m/s2.
We know the formula for calculating the force acting on a body is given by:
F= m x a where m is the mass of the body and a is the acceleration
Therefore, F= 500 x 5
F= 2500 N
4.What is the formula for gravitational force?
In Newtonian mechanics, the formula is given as follows.
\[ F_{g} = \frac{G m_{1} m_{2}}{r^{2}} \]
Here, G is the universal gravitational constant, m1 and m2 are the two masses of objects, and r is the distance between them. F is the magnitude of the gravitational force acting on each object, and the force will be directed towards the other object. The formula assumes point-shaped objects, which of course doesn't exist, but in most cases, when objects are far from each other, relative to their size, objects are assumed to be point-shaped, with their entire mass located at their respective centre of the object.
5. Differentiate between the gravitational force and the frictional force?
Gravitational Force: When two objects have mass or matter, there exists gravitational force between them. Gravitational force can be considered an attractive force because it keeps pulling the object to it. It is a non-contact type of force, for example, the gravity of the earth.
Frictional Force: Frictional force is the force that acts on a moving object. A moving object will be in continuous contact with the surface. The surface exerts a force in the opposite direction of the moving object, which is called frictional force. It is a contact type of force. For example, a ball rolling on the ground.
