Download Newton`s 3rd Law

What will happen?
https://www.youtube.com/watch?v=Z3xyqfCZmSU skateboards
https://www.youtube.com/watch?v=1jvr5UPudUk chairs
Newton’s
rd
3
Law of Motion
•For every action,
there is an equal
and opposite
reaction.
What does this mean?
• For every force acting on an object,
there is an equal force acting in the
opposite direction.
• For example: gravity is pulling you
down in your seat, but Newton’s
Third Law says your seat is pushing
up against you with equal force.
• This is why you are not moving.
There is a balanced force acting on
you– gravity pulling down, your seat
pushing up.
For every action, there is an equal and
opposite reaction.
For every action, there is an equal and
opposite reaction.
For every action, there is an equal and opposite reaction.
• The baseball applies a force
the bat (an action); and the
bat applies a force to the ball
(the reaction).
For every action, there is an equal and
opposite reaction.
• A car’s wheels spin, they grip the road and push the road
backwards (Action)
• The car moves forwards (reaction)
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For every action, there is an opposite an equal
reaction.
• If I push on a wall, what will
happen?
• The wall will push back
• What if I try to twist a screwdriver?
• The screwdriver will twist back.
• On earth this is not a problem, my
feet have enough friction to hold
me in place.
• But in outer space…
https://www.youtube.com/watch?v=PrJnWTcW55s
Physics of Rowing
• A crew team pushes the water
backwards to propel the boat
forwards.
Review of Newton’s three Laws
• 1st Law: Objects in motion tend to stay in motion
and objects at rest tend to stay at rest unless
acted upon by an unbalanced force.
• 2nd Law: Force equals mass times acceleration (F =
ma).
• 3rd Law: For every action there is an equal and
opposite reaction.
Review of Newton’s three laws on a bike
https://www.youtube.com/watch?v=JGO_zDWmkvk
Balloon Car Challenge
• Can you use your knowledge of motion
and forces to create a car that will travel
5m in the hallway using a single balloon
for power?
• Your materials are:
• Cardboard
• Four plastic lids
• Bamboo skewers
• Tape
• Straws
• balloon