As we already know, force is the push or pull that an object feels when it interacts with another object. This push or pull causes the object to change its state, either from rest or from moving in a straight line. Force can also cause an object’s shape to change. In general, the force can be broken down into two types: contact and non-contact force.
Let us begin to learn about these types of forces by first understanding what are non-contact forces.
What are Non-Contact Forces?
Definition:- Non-contact forces are the forces that act on bodies that are not in physical contact with one another. These forces are acting at a distance type of forces.
Types of non-contact forces are
1. Gravitational force
2. Magnetic force
3. Electrostatic force
4. Nuclear force
Let us now discuss each of the above-mentioned types of non-contact forces in detail with appropriate examples.
Types of Non-Contact Force
1. Gravitational Force
Often times you might have noticed different things falling on the Earth’s surface. You might have wondered why things on Earth, fall downwards not upwards. The reason is the Gravity of Earth. Force due to Gravity or Gravitational force was first explained by Sir Isaac Newton.
He discovered Gravity when he observed a falling apple. He then thought about the forces of nature. Eventually, he realized that the force that acts on the apple falling from the tree towards Earth is the same force that acts on all falling bodies. It is the force of Gravitation.
In fact, it is the same force that acts on all bodies that are on the surface of Earth. It is the same force that makes the Moon a satellite of Earth and binds Earth in an orbit around the Sun.
Why is Gravitational Force a non-contact force?
Gravitational force is a non-contact force because it is capable of acting on objects when they are not in contact with each other.
For example in the case of an Earth-Moon system both Earth and moon exert a force of Gravitation on each other but they are not in contact with each other. A similar argument can be given for the Earth-Sun system.
2. Magnetic Force
You might have seen a magnet like the one shown below in the figure
Magnets large or small are capable of attracting metals like iron even if they are kept at a certain distance from them.
Magnetic Force or force due to magnets is an action at a distance force. In other words, we can say that it is a type of non-contact force. Magnets are even capable of moving objects that are heavier than they are. Magnets can attract and repel depending on which ends are facing each other.
3. Electrostatic Force
The electrostatic force is another type of non-contact force which is observed in nature. You can observe this force in action through the following activity:
Activity
1. first rub the comb through your dry hairs
2. Now bring this comb near small bits of paper.
3. This comb would attract the bits of paper towards itself.
This happens because when the comb is rubbed in your hair it acquires an electric charge. This charge can be positive as well as negative. Electrostatic charges are capable of exerting force on other charged bodies even when they both are kept at some distance from each other.
Types of Forces Concept Map
Examples of Non-Contact Forces
Let us now look at some examples of non-contact forces of each type.
Examples of gravitational forces
- The gravitational force causes the moon to revolve around the Earth.
- The rotation of our solar system’s planets around the sun.
- When we jump on the ground, we can land back on our feet. This is the most basic example of gravitational force.
Examples of magnetic forces
- Maglev trains are high-speed trains that use magnets to maintain train cars levitating above tracks.
- Magnetic force is used on contemporary roller coasters to keep the cars on the tracks.
- We all know that compasses are used to find direction. The compass consists of a tiny magnet known as the needle of the compass. The magnet is attracted or repelled by the Earth’s magnetic poles, indicating its direction.
Examples of Electrostatic Force
- Because of the charged particles on the garment, a silk shirt clings to the body. When removing a woollen sweater, the same rule applies.
- Electrostatic forces draw sugar grains to the interior surface of a container.
Frequently asked questions
What are the 4 non-contact forces?
Four types of non-contact forces includes
- Gravitational Force
- Magnetic Force
- Electric Force
- Nuclear Force (strong and weak nuclear forces)
What are the 5 examples of non-contact forces?
Five Examples of non-contact forces are
- A ball thrown upwards falls towards the ground because of the gravitational force of attraction between the ball and the Earth.
- Comb run through dry hairs becomes electrically charged and attracts small bits of straws and papers.
- Raindrops fall on the ground under the effect of gravity.
- Because of the magnetic force operating on iron nails, a magnet attracts iron nails.
- The navigation compass also works on the principle of magnetism. It makes use of the alignment of compass needles in the Earth’s magnetic field.
Is static electricity a non-contact force?
Yes, static electricity is a non-contact force. Electrostatic forces pull or push on objects without making contact with them.
