Transcript Newton intro with hover pucks

A ball released and allowed to
roll down one ramp and it
quickly slows to a stop rolling
up the next ramp in A.
The same ball is released and
allowed to roll down the ramp
and it slowly slows to a stop
rolling up the next ramp in B.
The same ball is released and
allowed to roll down the ramp
and onto a smooth horizontal
surface.
1. What do you think will
happen to the ball in C?
This is a photo of a car seat
advertised in the 1950’s.
Seat belts are not part of the
design.
2. Carefully examine the
early car seat model shown
above. If the car was
moving forward and came
to a sudden stop, what
would happen?
This polar bear slipped and
fell on the ice.
3. What would have
prevented this bear from
slipping? What is unique
about the surface it slipped
on?
2 straws and a marble
1. What did you have to exert on the marble to get it to start
moving?
2. What did you have to exert on the marble in order to
slow it to a stop?
3. What did you have to exert on the marble in order to
change its direction?
4. If the marble was rolling along, did you have to exert a
force to keep it rolling?
5. In the absence of friction, and with an infinitely long table
top, once the marble is rolling, would it stop on its own?
Add to Force and Motion Notes
• What are some examples of forces:
– Friction (opposes motion, goes in opposite direction)
– Normal (supporting force ex: chair pushing up on your butt, table
holding the TV)
– Tension (pulling force along a wire or string)
– Gravity (attractive force between masses)
– Applied (push or pull exerted by an outside object)
• Remember we need an unbalanced forced to cause a change in
motion.
• The motion will not change if the forces acting on it are ZERO!
• Tendency of an object to maintain its present motion or no motion is
INERTIA
Eureka
•
Inertia – (start at 1:20) http://www.youtube.com/watch?v=by7kkAu2Pg
• **Mass **
http://www.youtube.com/watch?v=uvy4nWh0KwE&feature=related
• What is another word for Inertia?
laziness
• Inertia is related to what property of matter?
mass
Hover pucks
• Describe before
during and after
• Design a situation in
which the hover puck
moves with constant
velocity.