Newton's first law of motion states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external unbalanced force. It defines inertia as the tendency of a body to maintain its state of motion or rest. Inertia can be classified as inertia of rest, where an object wants to remain at rest, or inertia of motion, where a moving object wants to keep moving. Balanced forces do not cause a change in motion, while unbalanced forces can change an object's motion.

1. NEWTON’S FIRST LAW OF MOTION
SUBMITTED BY
DHANYA MOL C
PHYSICAL SCIENCE
ROLL.NO: 6
ZAINAB MEMORIAL
COLLEGE OF TEACHER EDUCATION
CHERKALA.

2. CONTENTS:
Introduction
Newton’s first law of motion
 Balanced and unbalanced forces
Inertia
Classification of inertia

3. INTRODUCTION
 According to Aristotle, a moving object must be
propelled by a steady force and,
 Galileo stated that, in the absence of a force , a
moving object will continue moving.
 Newton refined Galileo’s idea and made it his first
law, appropriately called the law of inertia.

5. NEWTON’S FIRST LAW OF MOTION
“Every body continues to be in its state of
rest or of uniform motion in a straight
line unless acted upon by an external
unbalanced force”.

6. What is unbalanced force?

7. Balanced and unbalanced forces
Balanced force Unbalanced force
 Equal magnitude
 Opposite direction
 Do not cause change in
motion
 Unequal
 Can be in the same or
opposite direction
 Causes change in
motion

8.  The key word in this law is continues : an
object continues to do whatever it
happens to be doing unless a force is
exerted upon it.
 Newoton’s first law defines inertia.

9. Inertia :
The tendency of a body to maintain its
state of rest or of uniform motion in a
Straight line is called inertia.
Inertia can be classified in to two.

10. Inertia
Inertia of rest Inertia of motion

11. Inertia of rest:
It is the tendency of a body to continue in its
state of rest.
Inertia of motion:
It is the tendency of a body to continue its
motion.