Homework Due

Read & Study 9.3-9.4, do #8-12 p. 133

Tonight’s HW

• Read & Study 9.5; do #13-15 • (3 points)

• Finish today’s WebQuest if necessary

• Prepare for Open Notes Quest next class!

Do Now • 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/ladybug-motion-2d

#1. The ladybug moves CLOCKWISE. What could the FORCE and VELOCITY vectors, respectively, look like?

A. B. C. D.

5%0%

95%

0%

A. B. 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, look like?

A. B. C. D.

32%

0%

68%

0%

A. B. 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.

20%

60%

0%0%

20%

A. B. C. 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. B. C. D.

0%

100%

0%0%

A. Bug XB. Bug YC. Not enough

info to sayD. Same

#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.

25%

40%

25%

5%5%

A. B. C. 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. E. F.

89%

5%0%0%0%

5%

A. Inward, towards the centerB. Curved, In a circleC. Tangent D. Curved, away from the

circleE. Outward, away from the

centerF. None of the above

2. If you were to remove that force from the object, the object would take a path that looked like

A. B. C. D. E. F.

10%

0% 0%0%

15%

75%

A. Inward, towards the centerB. Curved, In a circleC. Tangent D. Curved, away from the

circleE. Outward, away from the

centerF. None of the above

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?

A. B. C.

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0%0%

A. RightB. LeftC. Neither

• 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/CarAndCurve.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. B. C. D.

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70%

5%

15%

A. Gravity B. Support force C. Centrifugal force due to

friction D. Centripetal force due

to friction

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?

A. B. C.

22%

6%

72%

A. Outside seatB. Inside seatC. Doesn’t matter

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=DtNVLEXzcvM

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?

A. B. C. D. E. F.

0% 0%6%

0%0%

94%

A. Inward, towards the centerB. Curved, In a circleC. Tangent D. Curved, away from the

circleE. Outward, away from the

centerF. None of the above

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. 2. 3. 4.

50%

11%

0%

39%

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

8. Explain why various race tracks have banked curves – or inclined walls.

http://www.youtube.com/watch?v=HmFMAGxGavY

1. 2. 3. 4.

72%

6%0%

22%

1. More centripetal force2. Less centripetal force3. More centrifugal force4. Less centrifugal force

Concept Development • On the back of your Study Guide • Complete this!• We are going over this in 5 minutes!

Remember – YOU want to move according to Newton’s 1st Law – no change in motion. Only a FORCE will change your motion. Remove the force (in this case, back of seat), you tend to stay at rest.

Remember – YOU want to move according to Newton’s 1st Law – no change in motion. Only a FORCE will change your motion. Remove the force (in this case, seatbelt), you tend to keep a constant velocity.

Remember – YOU want to move according to Newton’s 1st Law – Straight line, same speed. Only a FORCE will change your motion. Remove the force (in this case, seatbelt and car door), you tend to keep a constant, TANGENT velocity – you would fly out of the car by virtue of your inertia, since there would be NO force on you!

**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)