Page 1 - LN-Balanced Unbalanced force

SAI INTERNTIONAL SCHOOL
Class 8
Lesson Notes
Subject- Physics
Ch- Force and Pressure
Subtopic- Balanced and unbalanced force

RESULTANT FORCE
Definition: The net force experienced by the body when two or more forces are
acting on the body is called resultant force.
It is the force which has same effect on the body as all the forces together.

a) When forces are applied on the body in the same direction they add to one
another.
Resultant force: magnitude= F1+ F2 ; Direction same as F1 & F2

b) When forces act on a body in opposite directions the net force acting on it is
the difference between the two forces.
Resultant Force: magnitude= F1-F2 ……………..(when F1>F2)
Resultant Force: Magnitude= F2-F1 ………….….(when F2>F1)
Direction: same as the direction of greater force

c) When two forces are equal and opposite the resultant force is zero and the
body does not change its state of motion. The forces are balanced force.
Resultant Force = F1-F2…………..(when F1=F2)
= 0

BALANCED FORCE:
When the net force acting on a body or the resultant force is 0, then it is called
balanced force. There is no change in state of motion of an object under the
balanced force.
Eg: notebook kept on the table. Downward gravitational force is balanced by
equal upward Normal force. So the book does not move.

UNBALANCED FORCE:
When the net force acting on a body or resultant force is not zero, then it is
called unbalanced force.
Eg: shifting a table. The force is applied only from only one direction, so the
table moves according to the applied unbalanced force.

REFER:
https://www.khanacademy.org/science/physics/forces-newtons-laws/balanced
-unbalanced-forces/v/balanced-and-unbalanced-forces