# Physics,

Physics –  Force

1- Force -It is a physical quantity which changes or tend to change the position of a body.

2-If there is physical contact between the two bodies which are interacting then the force applied is called Contact force.

3-Muscular force, force of friction, normal force , tension are examples of contact force.

4-The force which we exerts by using our body muscles is known as muscular force.

5-Force of friction means friction is the force that opposes relative motion of surfaces in contact.

6-The force which is acting opposite to gravitational force and perpendicular to surface of contact is called normal force.

7-Whe you try to stretch a rope or a string the tightness of rope or string is called tension.

8-Forces that change the motion of an object without actual touching is called non contact force.This is also called force acting at a distance.

9-Magnetic force, electrostatic force and gravitational force are examples of non contact force.

10-The attractive force between any two massive objects in the universe is called  gravitational force.

11-The force exerted by a charged body on other charged or uncharged body is known as electrostatic force.

12-The force exerted by a magnet on another magnet is called magnetic force. The magnetic force also acts on magnetic materials such as iron.

13-Force is a push or a pull. Force can act on an object with or without being in contact.

14-At least two objects must interact for a force to come into play.

15-Net Force – It is the algebraic sum of all the forces acting on a body along the straight line.

16-Magnitude – The amount of force which is measured is known as magnitude of force.

17-Equilibrium -If the body does not move if two equal and opposite forces are applied then we say the body is in equilibrium.

18-State of motion -If the body is in motion then it is said to be in state of motion.

19- Pressure -If the force acting on unit area of a surface.

20-Free Body diagram – The diagram showing all the forces acting on an object at a particular instant is called free body diagram (FBD).