2. IndexObjectivesForceNewtons first lawInertiaNewtons second
lawNewtons third lawEnd!
3. ObjectivesUnderstand the ideas of motion and forceDescribe
Newtons three laws of motionUnderstand the idea of inertiaTest
Newtons three laws of motion intheir class room
4. WHEN THERE IS A PULL ...WHEN THERE IS A PUSH...WHEN THERE IS
A STRETCH...WHEN THERE IS A SQUEEZE ...WHEN THERE IS A TWIST...We
experiences some effect called forces.We cant see forces but we can
see the effect of aforce.Force
5. The ball remains in its state of rest till an externalforce
is acting on it.Newtons first law
6. When an external force (push) is acting on a ball (object)at
rest it changes its state (moves over the steps ).Newtons first law
(contd..)Push the ball
7. object in motion tends to stay in motionNewtons first law
(contd..)
8. When external force (Push of the rabbit)acting on the object
(ball) which is inmotion the object changes its position.Newtons
first law (contd..)Push the ball
9. From the above observation...Newtons first law (contd..)An
object remains in its state of restif no external force is acting
on it.An object remains in its state of motionif no external force
is acting on it.An object changes its state of rest or
uniformmotion if some external force acting on it.
10. An object at rest tends to stay at rest and an object
inmotion tends to stay in motion with the same speed andin the same
direction unless an external force is actingon it.The above three
statement can be written as a singlestatement which is the Newtons
first lawIn other wordsEvery body continuous in its state of rest
or in uniformmotion Unless an external force is acting on
it.Newtons first law (contd..)
11. When the car hits the wallThe moving car stopped when a
force (from thewall) is acting on it.Driver who is moving along
with the car could notable to stop himself when the car
stopped.Driver has inability to change his position byhimself at
that instant.Inertia
12. When the truck hits the carThe moving truck stopped when a
force (from the car) isacting on it.Ladder which is moving along
with the truck could not ableto stop itself when the truck
stopped.Ladder has inability to change its position by itself at
thatinstantInertia (contd..)
13. It is the natural tendency of objects to resist changes
intheir state of motion.This tendency to resist changes in their
state of motion isdescribed as inertia.This can be said in a single
statementInability of an object to change its position by itselfis
called Inertia.Inertia (contd..)
14. It is too hardIt is very easySmaller force is needed to
move smaller massLarger force is needed to move larger massNewtons
second law
15. 10 n30 nSmaller force give smaller accelerationLarger force
give Larger accelerationNewtons second law (contd..)
16. If a bowling ball and a soccer ball were both dropped at
the same time from the roof of a tall building, whichwould hit the
ground with a greater force?Acceleration due to gravity accelerates
downwards all objects at the same rate.Therefore the difference in
forces would be caused by the different masses of the balls.The
mass of the bowling ball is greater than the mass of the soccer
ball.The bowling ball experience greater force than soccer ball.So,
bowling ball hit the ground first.Newtons second law (contd..)
17. Smaller force (F) is needed to move smaller mass (m)Larger
force (F) is needed to move larger mass (m)So, Force is directly
proportional to massF mSmaller force (F) give smaller acceleration
(a).Larger force (F) give smaller acceleration (a).So, Force is
directly proportional to acceleration (a).F aAcceleration is
produced when a force acts on a mass.The greater the mass (of the
object being accelerated) the greater the amount of force needed
(toaccelerate the object).Newtons second law states that the net
force on anobject is proportional to the mass and the
accelerationthat the object undergoes.F = maNewtons second law
(contd..)
18. Look at the flying motion of birds.A bird flies by the use
of its wings.The wings of a bird push air downwards.The air reacts
by pushing the bird upwards.The direction of the force on the
air(downwards) is opposite to the direction of theforce on the bird
(upwards).These two forces are equal and
opposite.actionreactionNewtons third law
19. Look at the flying motion of rocket.Hot gases are pushed
out from the bottom ofthe rocket as the rocket is thrust upward.The
force of the gases pushing against thesurface of the earth is equal
and opposite tothe force with which the rocket movesupward.These
two forces are equal and opposite.Newtons third law (contd..)
20. Look at the recoil effect of the gun.When we trigger the
gun, the gun pushes thebullet forwards and the bullet pushes the
gunbackwards.The bullet has a greater acceleration due to thefact
that it has a smaller mass. (Newtonssecond law)These two forces are
equal and opposite.actionreactionTrigger the gunNewtons third law
(contd..)