Homework
Due
Tonight’s
HW
Do Now
Read & Study 9.3-9.4, do #8-12 p. 133
• Read & Study 9.5; do #13-15
• (3 points)
• Finish today’s WebQuest if
necessary
• Prepare for Open Notes Quest
next class!
• Turn in HW
• Take back your Ladybug Exit Slip
from last class
• Take a Clicker from my desk –
• Channel 50 Channel
Use this as a hint…
• http://phet.colorado.edu/en/simulation/ladyb
ug-motion-2d
#1. The ladybug moves CLOCKWISE.
What could the FORCE and VELOCITY
vectors, respectively, look like?
95%
A.
B.
C.
D.
5%
A.
0%
B.
0%
C.
D.
Do Now Answers
#1. The ladybug moves CLOCKWISE. What
could the FORCE and VELOCITY vectors,
respectively, look like? (A, B, C, or D)
#2. The ladybug moves CLOCKWISE.
What could the ACCELERATION and
VELOCITY vectors, respectively,68%
look
like?
A.
B.
C.
D.
32%
0%
A.
B.
0%
C.
D.
Do Now Answers
#2. The ladybug moves CLOCKWISE. What
could the ACCELERATION and VELOCITY
vectors, respectively, look like? (A, B, C, or D)
Do Now Answers
#3. The ladybug moves COUNTERCLOCKWISE.
Draw and Label the FORCE, ACCELERATION,
and VELOCITY vectors.
#4. Imagine the bugs are attached to
a bar as shown. What would the
TANGENTIAL VELOCITY vectors look
like at points X & Y?
A.
B.
C.
D.
E.
60%
20%
A.
20%
B.
C.
0%
0%
D.
E.
Do Now Answers
#4. Imagine the bugs are attached to a bar as
shown.
CHECK QUESTION!!
Imagine the bugs are attached to a
bar as shown. Which bug has the
larger ROTATIONAL VELOCITY?
A. Bug X
B. Bug Y
C. Not enough
info to say
D. Same
100%
0%
A.
0%
B.
0%
C.
D.
#5. Imagine the bugs are attached to
a bar as shown. What would the
ACCELERATION vectors look like at
points X & Y?
A.
B.
C.
D.
E.
40%
25%
25%
5%
A.
B.
C.
5%
D.
E.
Do Now Answers
#5 & 6!!!!
POGIL Review
• Turn to the summary
portion at end of
POGIL.
• 5 minutes to complete
#1-8
• We will we clicking in
as a class
1. The force that
causes an object to
move in a circular
path acts…
A.
B.
C.
D.
Inward, towards the center
Curved, In a circle
Tangent
Curved, away from the
circle
E. Outward, away from the
center
F. None of the above
89%
5%
A.
B.
5%
C.
0%
0%
0%
D.
E.
F.
2. If you were to
remove that force
from the object, the
object would take a
path that looked like
75%
A.
B.
C.
D.
Inward, towards the center
Curved, In a circle
Tangent
Curved, away from the
circle
E. Outward, away from the
center
F. None of the above
15%
10%
0%
A.
B.
C.
D.
0%
0%
E.
F.
3. You are traveling in the passenger seat of a
car. All of the sudden, the driver makes a sharp
LEFT turn. Do you feel as if you are moving to
the right, or the left?
100%
A. Right
B. Left
C. Neither
0%
A.
B.
0%
C.
• Imagine that you are a passenger in a car which is
making a left turn.
– As the car begins to take the turn to the left, you
often feel as though you are sliding to the right.
– The car is turning to the left due to the inward
CENTRIPETAL force, yet you feel as though you are being
forced rightward or outward.
– In actuality, the car is beginning its turning motion (to
the left) while you continue in a straight line path. This
motion can be better understood by examining the
animation below.
– http://www.physicsclassroom.com/mmedia/circmot/rht.
cfm
– http://www.mrwaynesclass.com/teacher/circular/CarAn
dCurve.htm
4. When a car travels in a circular path, what
force holds the car in the curved path? (Hint: Is
it easy to maneuver a car when road conditions
are icy?)
A. Gravity
B. Support force
C. Centrifugal force due to
friction
D. Centripetal force due
to friction
70%
15%
10%
A.
5%
B.
C.
D.
5. Please answer the following question: When
riding the “Himalaya” or “Music Express” carnival
rides, is it more comfortable to sit on the outside
seat or the seat closer to the center? Why?
72%
A. Outside seat
B. Inside seat
C. Doesn’t matter
22%
6%
A.
B.
C.
5. Please answer the following question: When
riding the “Himalaya” or “Music Express” carnival
rides, is it more comfortable to sit on the outside
seat or the seat closer to the center? Why?
http://www.youtube.com/watch?v=DtNVLEXzcv
M
6. Suppose you were to
let go of the string
holding the water
bottle. (DO NOT DO
THIS) What path would
the water bottle follow?
94%
A.
B.
C.
D.
Inward, towards the center
Curved, In a circle
Tangent
Curved, away from the
circle
E. Outward, away from the
center
F. None of the above
6%
0%
0%
A.
B.
C.
0%
0%
D.
E.
F.
7. Picture a washing machine drum. It rotates,
and has holes in the side of the drum. Is the
water being forced away from the clothes, or
are the clothes being forced away from the
water?
1. The water is being forced
away from the clothes
2. The clothes are being forced
away from the water
3. Neither the clothes nor
water are being forced
4. Both the clothes and water
are being forced
50%
39%
11%
0%
1.
2.
3.
4.
8. Explain why various race
tracks have banked curves – or
inclined walls.
http://www.youtube.com/watch
?v=HmFMAGxGavY
1.
2.
3.
4.
More centripetal force
Less centripetal force
More centrifugal force
Less centrifugal force
72%
22%
6%
0%
1.
2.
3.
4.
Concept Development
• On the back of your Study Guide
• Complete this!
• We are going over this in 5 minutes!
**Summary**
• CENTRIPETAL force is always inward, towards the
center of the circle. (So is the acceleration! Object is
changing direction, so its velocity is changing, so it is
accelerating INWARD just like the force!)
• CENTRIPETAL force causes objects to MOVE in a
circular path
• CENTRIFUGAL is the FEELING of being thrown outward
(due to INERTIA / 1st Law), but it is not a real force!
There is NEVER a force that throws you “outward”
• When you turn, CENTRIPETAL force keeps you turning.
Remove the force, you move in a tangent path because
there is NO FORCE acting on you – you move by virtue
of your own inertia / Newton’s 1st Law!
Concept Development
• On the back of your Study Guide
• Complete this!
• Check in w/ teacher to review (you WILL see this on
your test)
• Then, you will receive a Web Quest….
• You have the rest of class to prep for your quest by
completing the…
– Web Quest (not collecting or grading…but some of the
questions will be on your Quest)
– Study Guide (not collecting or grading…but some of the
questions will be on your Quest)
– Tonight’s HW (#13-15, 3 points)
At this time…
• Return your CLICKERS!
• You have the rest of class to prep for your quest by
completing the…
– Web Quest (not collecting or grading…but some of the
questions will be on your Quest)
– Study Guide (not collecting or grading…but some of the
questions will be on your Quest)
– Tonight’s HW (#13-15, 3 points)
• Next class we will…
– Review HW #8-15
– Take the quest
– Start Ch. 12 (Big Bang, Black Holes, Universal Gravitation)