Force and Motion
Concept: Force and Its Types
What is force?
A push or a pull on an object is called force. Force is the reason why motion is created on an object.
How does force interact with objects?
- The interaction between one object with another results in a force acting between the two objects.
- If two bodies exert force on an object from the opposite direction, then the total force would be the difference between the two forces exerted by the two bodies.
- If two bodies exert force in the same direction on the same object, then the total force acting on that object would be the sum of both the forces exerted by the two bodies.
Characteristics of force:
- Force has the ability to make a body that is at rest to move.
- Force can stop a moving body or slow it down.
- It can increase the speed of a moving body.
- Force can change the direction of a moving body.
- Force can alter the shape and size of a body.
Types of force:
Force can be broadly classified into contact and non-contact forces.
1. Contact force:
- These forces act on bodies only when they are in physical contact.
- No attraction or repulsion occurs between the two objects.
Examples: Muscular force, frictional force, and mechanical force.
2. Non-contact force:
- These forces act on bodies that are not in physical contact.
- Attraction or repulsion exists between the two objects.
Examples: Gravitational force, electrostatic force, and magnetic force.
Types of contact forces:
1. Muscular force:
- This force is applied by using different parts of the body like arms and legs.
- This force is exerted due to the action of our body muscles.
- Muscular force is a type of contact force, so our body touches the object while exerting the force.
2. Frictional force:
- The frictional force is always exerted from opposite directions and is a type of contact force.
- Friction happens when two surfaces rub against each other.
- Such a type of force can slow down or stop a moving object.
3. Mechanical force:
- This type of contact force is generated by machines on another object.
- Mechanical force features a direct contact between two objects.
Types of non-contact forces:
1. Gravitational force:
- Gravitational force is the attractive force that is exerted by the earth on other bodies.
- Due to this gravitational force, the earth pulls everything towards itself.
2. Magnetic force:
- A magnet can exert a force on another magnetic object without touching it.
- Such a force creates either attraction or repulsion between electrically charged particles because of their motion.
3. Electrostatic force:
- It is a type of non-contact force.
- A charged body exerts such a force on another charged or uncharged body.
- There is a force of attraction between unlike charges and a force of repulsion between like charges.
Attractive force: It is the force that draws one object towards another.
Repulsive force: It is the force that makes one object move away from another.
Like and unlike charges: Charges with the same sign, i.e., positive-positive, are called like charges. Charges with the opposite sign, i.e., positive-negative charges, are called, unlike charges.
Did You Know?
- When an object is partially or totally immersed in a liquid, a force is exerted upwardly on that object called the buoyant force.
- A lighter object is pulled by the earth very slowly, whereas a heavier object is pulled by the earth rapidly. It means that the higher the mass, the greater the gravitational force.