2. FORCE
It is an external agency which
changes or tends to change the
state of motion or direction of its
motion or the shape of An object is
known as force.
The unit of force is newton (N).
3. NEWTON’S 1ST LAW OF MOTION
Acc. to newton’s 1st law of
motion, an object continues to be
in its state of rest or state of
motion along a straight line until
and unless an external unbalanced
force is applied to it
It is also known as law of inertia.*It
also defines force
4. INERTIA
Inertia is the resistance of any physical
object to any change in its state of motion
(this includes changes to its speed, direction
or state of rest). It is the tendency of objects
to keep moving in a straight line at constant
velocity.
5. TYPES OF INERTIA
1. Inertia Of Rest: An Object Tends To Be In State
Of Rest Until & Unless An External & Unbalanced
Force Is Acted Upon It.
2. Inertia Of Motion: It Is That Inherent Property Of
A Material By Virtue Of Which It Resists Any
Change In Its State Of Motion. .
3. Inertia Of Direction: It Is A Inherent Property Of A
Material By Virtue Of Which It Resists Any
Change In Its Direction Of Motion.
6. MOMENTUM
Quantity of motion contained in a
body is known as momentum and is
measured as product of mass of an
object and its velocity
p = mv
7. NEWTON’S 2ND LAW OF MOTION
It states that the rate of change of
momentum is directly proportional to
the force applied and change takes
place in the direction of force applied
Alternatively, it is also stated as the
force is directly proportional to
product of mass and acceleration
produced by the force.
F = m*a
8. IMPULSE
Impulse is the change of momentum
of an object when the object is acted
upon by a force for an interval of time.
9. NEWTON’S 3RD LAW OF MOTION
It states that every action has
equal and opposite reaction.
By newton’s 3rd law of motion
Faction=-Freaction
10. FRICTION
When an object moves or tends
to move ,that opposing force
which comes into play is known
as friction.
11. CAUSES OF FRICTION
The apparent are of contact
The intermolecular forces:
cohesive and adhesive forces
between the two material bodies
12. TYPES OF FRICTION:
Static friction: the force of friction which
comes into play when a body is at rest over
the surface of other.
Limiting friction: the maximum value of
static friction which comes into play when
body is at the verge moving.
Kinetic friction: the force of friction which
acts on a actually moving body.
13. COEFFICIENT OF FRICTION
μ is called coefficient of limiting
friction and is defined as the ratio of
limiting friction to the normal reaction
between the two surfaces in contact.
F
F R
F = R
= F/R
14. ANGLE OF FRICTION
It is defined as the angle which the resultant
of limiting friction and normal reaction
makes with the normal reaction
15. ANGLE OF REPOSE
It is defined as angle which an inclined plane
makes with the horizontal such that body kept
on it just starts moving.
= angle of repose
17. ADVANTAGES OF FRICTION
Walking is because of friction
No two bodies will stick to each other
Vehicle’s braking system works because
of friction
Nuts and bolts would not be able to hold
the machinery together
Writing would not be possible
Adhesive will loose their purpose
18. DISADVANTAGES OF FRICTION
Friction always opposes motion,
therefore extra energy is required to
overcome friction
Wear and tear of machinery is
caused by friction
Friction causes production of heat
which damages the machinery
