1. Day 8 of 3rd Quarter
1) Talk about HW
2) Probs
3) New topic at end

2. When you leave here today
You will know how to relate motion in a circle to Newton’s Laws.
You will know the difference between CENTRIPEDAL motion and TANGENTAL motion

3. HW
Answers online,
How can I help you out with this?

4. ON WATCH
Quiz on all topics: Ballistic Pendulums Pendulums Gravitation/Gravity Springs Orbits
Fri 10th /Mon 13th

5. PARTNERS

6. Here a satellite is orbiting in an ellipse and is measured from the Earth’s center.
We want to find the velocity at the ? in terms of the variables given AND the earths mass Me.

7. Please create a table of values at R1 and R2

8. Is the work here + - or 0

9. What is the work done on the satellite here 0, + or -

10. Curved track in the hall

12. Statements:
You can have an acceleration even if the magnitude of the velocity is constant.
T/F?

13. Statements:
You can have an acceleration even if the magnitude of the velocity is constant.
TRUE! If the direction changes, there is an acceleration!

14. Statements:
You need an imbalance of forces in order to change the direction of an objects motion
T/F?

15. Statements:
You need an imbalance of forces in order to change the direction of an objects motion
TRUE! Newton's 1st law states that stuff keeps doing what its doing until an imbalance occurs

16. Question: Remember Orbits
So for something going in a CIRCLE, or in a CIRCULAR CURVE, which way must the imbalance be?

17. Question: Remember Orbits
So for something going in a CIRCLE, or in a CIRCULAR CURVE, which way must the imbalance be?
Towards the center of the circle!

18. TANGENTAL ACCELERATION changes amount
CENTRIPEDAL ACCELERATION changes the direction
ONLY FOR CIRCLES

19. Do these 2 accelerations affect each other?
NO, because they are 90 degrees to each other (X and Y independence)
FOR CIRCLES ONLY, elliptical orbits are different

21. From points A to E, there is negative work done (SLOWING).
From E to A, there is positive work done (SPEEDING UP)

22. PLEASE WRITE A SENTENCE EXPLAINING THE WORK DONE ANOTHER WAY…
From A to E, part of the velocity is opposite the direction of force which is a negative work
This is an ISOLATED system, so from A to E the GRAVITATIONAL ENERGY is going up (farther from Earth), so KE decreases which is a negative work