Computer Application- Newton’s laws of motion First Law Second Law Third Law Law of Inertia Types of Friction Friction Second Law of Motion Units & Measures Third Law of Motion

1. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Affiliated Institution of G.G.S.IP.U, Delhi
PHYSICS
Paper Id: 20109
Paper code: BCA 109
Topic: LAWS OF MOTION
Yugshakti
Assistant professor(IT)

2. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Newton’s Laws of Motion
First Law – An object at rest will stay at rest, and an
object in motion will stay in motion at constant velocity,
unless acted upon by an unbalanced force.
Second Law – Force equals mass times acceleration.
Third Law – For every action there is an equal and
opposite reaction.

3. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
• It states that every body continues to
its state of rest or of uniform motion
in a straight line, unless it is
compelled by some external force to
change that state.
First Law of Motion
(Law of Inertia)

4. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Affiliated Institution of G.G.S.IP.U, Delhi

5. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Friction
Why then, do we observe every day objects in
motion slowing down and becoming motionless
seemingly without an outside force?
It’s a force we sometimes cannot see – friction.
Definition: Friction is the force that is set up
between the surfaces of contact , when one body
slides or rolls or tends to do so on the surface on
another body.

6. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Types of Friction
• There are four main types of friction:
–Sliding friction: ice skating
–Rolling friction: bowling
–Fluid friction (air or liquid): air or water
resistance
–Static friction: initial friction when moving
an object

7. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Example: Friction
Slide a book across a table and watch it slide to
a rest position. The book comes to a rest because
of the presence of a force - that force being the
force of friction - which brings the book to a rest
position.

8. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Second Law of Motion
• It states that the time rate of change of
momentum of a body is directly proportional
to the external force applied on it and the
change in momentum takes place in the
direction of force.
Or
The net force of an object is equal to the product
of its mass and acceleration, or F=ma

9. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Units & Measures
• When mass is in kilograms and acceleration is
in m/s/s, the unit of force is in newtons (N).
• One newton is equal to the force required to
accelerate one kilogram of mass at one
meter/second/second.

10. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75

11. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Third Law of Motion
For every action, there is an
equal and opposite reaction.

12. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Third Law
According to Newton,
whenever objects A and B
interact with each other,
they exert forces upon each
other. When you sit in your
chair, your body exerts a
downward force on the
chair and the chair exerts an
upward force on your body.

13. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Third Law
• There are two forces
resulting from this
interaction - a force
on the chair and a
force on your body.
These two forces are
called action and
reaction forces.

14. TRINITY INSTITUTE OF PROFESSIONAL STUDIES
Sector – 9, Dwarka Institutional Area, New Delhi-75
Example: Third Law
• Consider the flying motion of birds. A bird
flies by use of its wings. The wings of a bird
push air downwards. In turn, the air reacts by
pushing the bird upwards.
• The size of the force on the air equals the size
of the force on the bird; the direction of the
force on the air (downwards) is opposite the
direction of the force on the bird (upwards).
• Action-reaction force pairs make it possible for
birds to fly.