1. 1. No tutorials Wednesday morning 2. Santa’s little helper is next Monday, shopping for our little girl will be Thursday night at 6pm at Target. Please let me know if you plan to attend and give me your contact information. 3. You will need your notebook today- we are studying rotation and revolution

2.  Content- Distinguish between rotate and revolve  Language- Define rotate, revolve, linear (tangential) speed and rotational speed

4.  What is an axis? The (invisible) straight line around which a rotation takes place

5.  Rotation is defined as…?  When the object turns around an internal axis (the axis is located within the body of the object)  http://www.youtube. com/watch?v=9LzZ1 ORjSjk http://www.youtube. com/watch?v=9LzZ1 ORjSjk

6.  What does revolve mean?  Answer: When an object turns around an external axis

8.  The Earth ______ around the sun once every ____.  The Earth _____ around an axis (through it’s poles) once every _____.  Revolves  365.25 days  Rotates  24 hours

9. 1) Match the following terms: Orbit Revolve Spin Rotate 2) Which object rotates and which revolves? Top? Moon? Orbit → Revolve Spin → Rotate Rotates Revolves

10. Is it correct or incorrect to say that the Earth is rotating around the Sun? Why? It is rotating around its own axis, but revolving around the sun

11.  Which moves faster, the outer horse on a merry go round or the inner horse?

12. 2 types 1) Tangential Speed = Distance Time 2) Rotational Speed= Rotations Time

13. 1) Tangential Speed= Distance Time 2) Rotational Speed= Rotations Time  Revolutions /hr  Revolutions/s  Revolutions/min  Revolutions/day Have you ever heard of 45 rpm, 33 1/3 rpm A car’s engine is 2-3000 rpm  Rotations/yr  Rotations/week  Rotations/month

14.  At the center of the axis, do you have Tangential or rotational speed?  Rotational

15.  As you move outward do you increase your tangential or rotational speed?  Tangential

16.  1) Which part of the Earth’s surface has the greatest rotational speed? Linear speed?  All parts have the same rotational speed  The equator has the greatest linear speed

18.  In a rigid rotating system, all parts have the same (rotational, linear) speed, but the (rotational, linear) speed varies. rotational, linear Linear speed depends on the _____ from the axis of rotation and on the _____ speed. distance, rotational