This document discusses forces and Newton's laws of motion. It defines force and describes different types of forces like balanced and unbalanced forces. It then explains Newton's three laws of motion - inertia, relationship between force and acceleration, and action-reaction. The document also discusses related concepts like momentum, conservation of momentum and how forces can affect motion.

2. A PUSH OR PULL
ON A BODY IS
CALLED FORCE.
FORCES ARE USED
IN OUR EVERYDAY
ACTIONS LIKE
PUSHING,
PULLING, LIFTING,
STRECHING,
TWISTING AND
PRESSING.

3. EFFECTS OF FORCE
• A force cannot be seen. A force can be judged only by
the effects which it can produce in various bodies (or
objects) around us.
1. A force can move a stationary body.
2. A force can stop a moving body.
3. A force can change the speed of a moving body.
4. A force can change the direction of a moving body.
5. A force can change the shape and size of a body.

4. BALANCED AND UNBALANCED FORCE
• THERE ARE TWO KINDS OF FORCE:
• 1. BALANCED FORCE.
• 2. UNBALANCED FORCE.

5. BALANCEDFORCES
If the resultant of all the forces
acting on a body is zero, the
forces are called balanced
forces.
If a number of balanced forces
act on a stationary body, the
body continuous to remain in its
stationary position.
If a number of balanced forces
act on a body in uniform
motion, the body continuous to
be in its state of uniform
motion.
Though balanced forces
cannot produce motion in a
stationary body but can change
the shape of the body.

6. UNBALANCEDFORCE
If the resultant of all the forces
acting on a body is not zero, the
forces are called unbalanced
forces.
When an unbalanced force acts
on a body, it produces motion in
the body. Also, an unbalanced can
stop a moving body.
If there were no unbalanced
force of friction or air resistance,
a moving body would go on for
ever.

7. NEWTON’S LAW OF MOTION
NEWTON HAS GIVEN THREE
LAWS OF TO DEFINE THE
MOTION
OF BODIES. THESE
LAWS ARE KNOWN AS
NEWTON’S LAWS OF
MOTION.

8. NEWTON’S FIRST LAWOF MOTION
A body at rest will remain in
rest, and a body in motion
will continue in motion in a
straight line with uniform
speed, unless it is compelled
by an external force to change
its state of rest or of uniform
motion.
INERTIA: Inertia is that
property of a body due to
which it resists a change in
its state of rest or of uniform
motion.

9. MOMENTUM
The momentum of a body is defined
as the product of its mass and
velocity.
NOTE: the force required to stop a
moving body is directly proportional
to its mass and velocity.
Thus, momentum= mass x velocity
or, p= m x v
where p= momentum
m= mass of the body
and, v = speed of the body
SI UNIT= the SI unit of momentum
is kilogram meters per second
(kg.m/s)

10. NEWTON’SSECONDLAWOF MOTION
The rate of change of momentum of a
body is directly proportional to
applied force, and takes place in the
direction in which force acts.
Force= change in momentum/time
taken
f= mv-mu/t
f= m(v-u)/t. But we know that v-u/t
=a
f= m x a
force = mass x acceleration
SI UNIT: its SI unit is ‘force’.

11. NEWTON’S THIRD LAWOF MOTION
Whenever one body exerts a force on
another body, the second body exerts equal
and opposite force to the first body. OR,
To every action there is equal and opposite
reaction.
1. EX: the rocket works on the principal of
action and reaction.
2. When a bullet is fired from the gun, a
force sending the bullet forward is equal
to the force sending the gun backward.
But due to high mass of the gun, it
moves only a little distance backward
and gives jerk.

12. CONSERVATION OF MOMENTUM
When two or more bodies
act upon one another, their
total momentum remains
constant provided no
external forces are acting.
Momentum is neither
created nor destroyed.
Total momentum before
collision = total momentum
after collision