Download Name: Date: Aim 13: How does friction, air resistance and gravity

Name:
Date:
Aim 13: How does friction, air resistance and gravity affect the motion of object?
Do Now:
1. More friction causes an object to move (slower/faster). Less friction causes an object to move (slower/faster)
2. Suppose you roll a ball with your hand, the ball speeds up as you push it and then keeps moving after it
leaves your hand. What ends up happening to the ball’s speed if it is moving on a flat level surface?
.What force caused this?
A. What is FRICTION: A ________________ that causes ______________________ to motion when

Where is friction found? __________________________________________________________________

What causes friction? The ______________ of the frictional force exerted by one surface on another
depends on

How does the force of friction work? The force acts in the __________________________________ to the
way an object wants to move.
* Think about it: When you’re wearing shoes and you are running on a sidewalk, why can
you plant your feet and stop and do not keep sliding around?
* What happens when you run and stop in a puddle?

How does friction affect an objects motion?
MORE FRICTION (less smooth surface) =
LESS FRICTION (smooth surface) =
B. Why types of friction are there?
Static Friction

Velocity ____________________________

No _________________________________ of
objects past each other
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Sliding Friction

Velocity ______________________________

Object can __________________________
______________________________________


Rolling Friction
Round objects in contact with a solid
surface ______________________________

______________________________________
______________________________________
1. What is released when friction exists between two objects move past each other?
2. Why is it easier to move objects on wheels?
3. What would happen to the ball in our “do now” if friction was removed from the surface it was rolling
on?
4. What can we do to make object move faster?
5. Name some surfaces that have low friction and ways that can reduce the amount of friction between
objects.
6. Brake in bicycles work by pressing pads together on the wheels. This slows the bicycle due to
a. Centripetal force
b. Elastic force
c. Sliding friction
d. Static electricity
C. What is air resistance? An
that opposes the
*When objects fall, air resistance works UPWARD on the object*

Your pet elephant Rupert and a feather from your bird Winston were dropped off the
top of a building. Would the elephant or the feather fall first?

What if there was no air resistance?

Examine the two people in the parachutes. Which person will
fall to Earth faster? Explain!
D. What is gravity? The
force that
________________________________________________________________________________________________
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Gravity pulls ALL objects towards earth at the same rate of speed = 9.8 m/s2.
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MASSIVE objects have a
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When is the gravity between two objects the LARGEST?