Chapters 9,10,&11 review

Again, notes are recommended

Chap 9 stuff

• Explain the difference between linear speed and rotational speed.

• Explain the difference between rotation and revolution.

And then…

• Two ladybugs are on a turntable. One is at the edge and the other is 1/3 of the way out from the center. How much faster does one on the edge travel than the other?

• Which part of the earth’s surface has the greatest rotational speed?

• Which part has the greatest linear speed?

And then…

• What kind of force gives rise to circular motion?

• What is the difference between centripetal force and centrifugal force?

And then…

• Why does the water not fall out of the bucket when Dr. Mason swings it overhead?

• You are whirling a rock overhead on a string. If the string breaks, will the rock fly off in a straight line path because of centripetal force, centrifugal force or lack of force?

And then…

• A bug is at the bottom of a can that is being whirled overhead. There is an action/reaction pair of forces between the bug and the can. Which of these is the centripetal force and which is the centrifugal force?

Center of gravity stuff

• Define center of gravity• The complicated motion of a thrown baseball

bat can be reduced to what two kinds of motion?

And then…

• How do you find the CoG of a regularly shaped object?

• How do you find the CoG of an irregularly shaped object?

And then…

• Give examples of three objects whose centers of gravity are not where there is any material.

And then…

• When will an object topple over?

And then…

• Why can you not stand with your heels and back to the wall and bend over to touch your toes without falling over?

And then…

• How do tails help animals keep their balance?

And then…

• Why is the Seattle space needle stable?

And then…

• Explain how that crazy body bending way of clearing a high jump bar is, like, better.

And then…

• Why can you not stand on your toes when you are facing a wall?

And then…

• What is suggested by a star that wobbles off center?

And then…

• Why is a meter stick standing on end unstable but it’s stable when it hangs from one end?

And then…

• What happens to the CoG of a glass of water when a ping pong ball is pushed under the surface?

Chapter 11 stuff

• Define torque

And then…

• What two things can you do to increase torque?

And then…

• Explain the whole see saw thing with the balanced torques and stuff.

And then…

• What is newton’s first law?• Explain the rotational form of newton’s first

law.

And then…

• Why is it harder for a long-legged animal to move its legs fast than a short-legged animal?

And then…

• Explain rotational inertia

And then…

• What two factors influence rotational inertia?

And then…

• What does a gymnast do to rotate faster when performing a flip?