Transcript Newton`s Third Law of Motion

Newton’s Third Law of Motion
Warm up
State Newton’s first law of motion.
State Newton’s second law of motion.
Which one, force or mass, is directly proportional to
acceleration.
When the forces are balanced, do we have
acceleration?
Newton’s Third Law of Motion
KEY CONCEPTS
•WHAT IS NEWTON ’S THIRD LAW OF
MOTION?
•WHAT IS AN ACTION AND REACTION
FORCE?
•DESCRIBE HOW FORCES COME IN
PAIRS.
Introduction
Try to push the corner of
your table with the palm
of your hand.
What do you notice.
Introduction
Read the procedure of the
activity and do your
demonstration and then
record your observations
by filling in the designated
part on the activity sheet
Newton’s Third Law of Motion
If one object exerts a force on
another object, then the
second object exerts a force
of equal strength in the
opposite direction on the
first object
“For every action there is an
equal but opposite reaction”
Action – Reaction Pairs
 Kayak paddle pushes the water back,
the water pushes the kayak forward
 A dog pushes down on the ground,
the ground pushes up on the dog
causing it to leap into the air
Other Examples…….
Do Action – Reaction Forces Cancel?
 If 2 equal act in opposite directions they are balanced
and cancel each other out. There is no movement
 Action – Reaction forces do not cancel out because
they are acting on 2 different objects
Indicate which one is an action and which
one is a reaction force
Wrap up
 Newton’s Third law states that for every
action force there is an opposite and
equal reaction force.
 Action and reaction force don’t cancel
each other, since they are applied on
different objects.
 Forces occur in pairs.
 Homework:
 Section review questions #:
 Quiz on Monday, Nov. 28, 2011
1- Gravity
2-Third Law of motion