Force , Types of force , Characteristics of Force

                           Force 

Force is that external agent or cause which changes or tries to change position , location or shape of the body . It is denoted by 'F'. 

Units of Force :- 

The SI unit of force is Newton 'N' , 

The CGS unit of force is 'Dyne' ,

The British unit of force is 'Slug'

              Types of Forces 

Generally forces are divided in two categories :- 

 1- Contact Forces 

 2- Non Contact Forces 

                1- Contact Forces 

Those forces which acts on the physical contact between two objects / body , where one object exerts force on the other object . 

 Ex - Hitting the ball , Push the door ect . 

      Types of Contact Forces 

Contact forces are of following types which are given as :- 

1- Applied force / Muscular force 

2- Normal force 

3- Frictional force

4- Tension force 

5- Air resistance force 

6- Spring force 

1- Applied force :- That contact force which acts due to the action of muscles is known as applied force .

2- Normal force :- That contact force which acts perpendicular to the surfaces and out of surface is known as normal force .

3- Frictional force :- That contact force which acts when an object moves or try to move relative to a surface is known as frictional force. 

4- Tension force :- That contact force which applied through a string , cable , rope ect and pulled the object then it is known as tension force . 

5- Air resistance force :- That contact force which acts in a direction opposite to the motion by a air / gas is called air resistance force. 

         Air resistance force increases when the velocity  of the object  through the gas increases .

6- Spring force :- That contact force which acts due to displacement of molecules of spring is known as spring force . 

                        The direction of spring force is opposite to the displacement of spring . 

                2- Non Contact Forces

Those forces  which acts without physical contact between two objects but act through the space between objects is known as non contact forces . 

Ex - Gravitational force ect . 

      Types of Non Contact Forces

Basically non contact forces are of following types - 

1- Gravitational force

2- Electromagnetic Force

3- Weak nuclear force 

4- Strong nuclear force 

1- Gravitational force :- That non - contact force which acts due to attraction between two objects on the presence of matter is known as gravitational force . 

                Gravitational force is proportional to matter / mass . 

2- Electromagnetic Force :- That non - contact force which acts due to basic electric and magnetic interactions is known as electromagnetic force . 

                   Electromagnetic force is responsible for binding of atoms and the structure of solids . 

3- Weak nuclear force :- That non - contact force which causes certain radioactive among the most fundamental particle are known as weak nuclear force . 

4- Strong nuclear force :- That non - contact force which acts between the fundamental particles and is responsible for bonding the nucleus together is known as strong nuclear forces . 

Characteristics of a Force:- 

The characteristics of a Force are given below :- 

1- Force is a vector quantity as it has both magnitude and direction .

2- Every force is characterized by its magnitude direction and point of application . 

3- The direction and point of application together define its line of action . 

4- When force is applied on an object , it can produce motion of the object and deformation . 

5- The angular acceleration produced by the force would remain the same even if the force is shifted to any point of the line . 

6- When deformation of objects are studied due to forces , the forces must be considered as fixed vectors . That means there point of application can't be changed .