Question

there are three types of contact forces which are taught in class 8.....plzzz tell me all the three.

Answer 1

Friction force : it acts through the contact between two bodies. It acts along the surface in the direction opposite to the relative speed between the surfaces. It is equal to the coefficient of friction multiplied by the normal force between the surfaces.

Normal force: it is the contact force (it is the push between the two bodies). It acts perpendicular to the surface.  If a body is lying on a floor.  The body exerts a force equal to its weight on the floor.  Floor exerts a force on the bottom surface of the body equal to the weight of the body,

Muscular force , push or pull force or applied force :   The force you exert on a door, when you push the door. The applied force can be at any angle.

Spring force, - you have to  pull the string by touching , then only spring force acts. It is proportional to the extension and opposite to the direction of extension.

Tension force: It is the force developed in a string or thread or a thin material, when it is subjected to a push or pull at its ends.  This force is same all along the thread or rope or string. Tension makes the string or thread tight. It always acts inward from the ends to the center of the string.

Air resistance force or drag force : it is proportional to the velocity and is opposite to the movement of the body.

Buoyancy force in a fluid: it is equal to the weight of the fluid displaced by the body. It acts through the surface of the body immersed in a liquid.  This is how ships float on water.

Answer 2

┏─━─━─━─━∞◆∞━─━─━─━─┓
✭✮ӇЄƦЄ ƖƧ ƳƠƲƦ ƛƝƧƜЄƦ✮✭
┗─━─━─━─━∞◆∞━─━─━─━─┛

Force➫ Any interaction that when unopposed will change the motion of an object.

♦ It's SI unit is Newton (N).

♦ It has both magnitude & direction, making it a vector quantity.

♦ It can cause an object with mass to change its velocity to accelerate.

➊❭ Effects 0f Force are:-
▬▬▬▬▬▬▬▬▬▬▬▬▬⤵

❱ It can make a stationary object move or change its position of rest.

♦Ex:- When you kick a stationary Football it will in motion.

❱ It can change the speed of a moving object.

♦Ex:- When goalkeeper applies force to stop the football.

❱ It can change the direction of motion of a moving object.

♦Ex:- When a batsman hits a ball.

❱ It can change the shape or size of an object.

♦Ex:- When you squeeze a sponge.

❷❭ Types 0f Force are:-
▬▬▬▬▬▬▬▬▬▬▬▬▬⤵

❲1❳ Contact Force➫ A force that acts only when it is in contact with an object.

♦Ex:- Pushing a car up a hill.

❱ Types 0f Contact Force:-
▬▬▬▬▬▬▬▬▬▬▬▬▬⤵

❱ Muscular➾ The force which is exerted by the muscle of your body.

♦Ex:- When you lift your School's Bag.

❱ Frictional➾ The force generated by two surfaces that contacts & slide against each other.

♦Ex:- A person sliding down a slide.

❲2❳ Non-Contact Force➫ A force that acts on an object without being in contact with it.

♦Ex:- Leaves falling from a tree.

❱ Types 0f Non-Contact Force:-
▬▬▬▬▬▬▬▬▬▬▬▬▬⤵

❱ Gravitational➾ A force that attracts any two objects with mass.

♦Ex:- Leaves falling from trees.

❱ Magnetic➾ The force that arises due to the motion of charged particle within the magnetic field.

♦Ex:- Iron pin attracted to magnet.

❱ Electrostatic➾ The attraction or repulsion of particles or objects because of their electric charge.

♦Ex:- When you rub a comb in hair.

_________
Thanks...✊