This document discusses Newton's laws of motion and related concepts in physics. It defines force and describes the effects of forces. It explains balanced and unbalanced forces, and how unbalanced forces can cause motion, changes in speed or direction. Newton's three laws of motion are introduced, including inertia, relationships between force, mass and acceleration, and equal and opposite reaction forces. The concepts of momentum and conservation of momentum are also defined.

1. physics project work
Force and laws of motion

2. force
A push or pull on a body
is called FORCE .
Forces are used in our
everyday actions like
pushing , pulling , lifting
, stretching , etc.

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 . A force can produce the
following effects :
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 FORCES
Forces are of two types :
• BALANCED FORCES
• UNBALANCED FORCES

5. BalancedForces
If the resultant of all the forces acting
on a body is zero , the forces are called
balanced forces .
• Balanced forces doesn't change the
position of the body and appears as if
no force is acting on it
•Though , balanced force can’t
produce motion on a stationary body
or stop a moving body , but it can
change the shape of the body .

6. Unbalanced
Forces
If the resultant of all the forces acting on a
body is not zero , the force is called
unbalanced force . Unbalanced forces can do
the following:
• Move a stationary object .
• Increase the speed of a moving object .
• Decrease the speed of a moving object .
• Stop a moving object .
•Change the shape and size of the object .
•If there were no unbalanced force of friction
and no air resistance , a moving bicycle
would go on moving forever .
•.

7. Sir Isaac Newton
SirIsaacNewtonwasoneofthe greatestscientists
andmathematiciansthateverlived.He wasbornin
EnglandonDecember25,1643.He wasbornthe
sameyearthatGalileodied.He livedfor85years.
WhileNewtonwasincollegehe waswritinghisideas
in a journal.Newtonhadnewideasaboutmotion,
whichhe calledhisthreelawsofmotion.He alsohad
ideasaboutgravity,thediffractionoflight,and
forces.Newton'sideaswereso goodthatQueenAnne
knightedhimin 1705.Hisaccomplishmentslaidthe
foundationsformodernscienceandrevolutionized
theworld.SirIsaacNewtondiedin1727.
In thislessonyouwilldevelopanunderstandingof
eachof Newton'sThreeLawsofMotion.

8. Newton’s First Law of Motion
An objectat rest will remainat rest unlessactedon
by an unbalancedforce.An objectin motion
continuesin motionwith the same speedand in
the samedirectionunlessactedupon by an
unbalancedforce.
INERTIA: It is the propertyof a bodydue to whichit
resista change in its stateof rest or of uniform
motion.

9. Momentum
Momentum of a body is defined as the
product of its mass and velocity .
Momentum = massXvelocity
Or, p=mXv
It is a vector quantity having both
magnitude and direction .
SI UNIT = kg.m/s

10. Newton's Second Law of Motion
Accelerationisproducedwhena forceactson a
mass.Thegreaterthe mass(oftheobject
beingaccelerated)the greatertheamountof
forceneeded(toacceleratetheobject).
theSecondLawgivesus anexactrelationship
betweenforce,mass, andacceleration. It can
be expressedas a mathematicalequation:
F = ma
Or, Force = mass x velocity

11. Newton's Third Law of Motion
For everyaction there is an equaland opposite
re-action.
This meansthat for everyforcethere is a
reactionforce that is equal in size, but
oppositein direction. That is to say that
whenever an object pushes another object it
gets pushedbackin the opposite direction
equallyhard.

12. Law of 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.
• Can we apply this law for a collisionbetween
twovehicles? Yes, we can! This law is
applicable for all types of collisions.

13. Made By
Sanaa Sial
Student of class IX
D.AV. ACC Public School , Katni