Warmup #19: Gravity

Course

Please type your name:

Please type your LAST NAME and LAST FOUR SS# digits:

IN:
The first three questions refer to the material you were to read in preparation for the lesson. Questions one and two require you to write a three or four sentence response. Number three is a multiple choice question. Click in the appropriate circle. Questions 4 is your opportunity to suggest what we should emphasize today and how.

You may change your mind as often as you wish. When you are satisfied with your responses, click the SUBMIT button at the bottom of this page.


1.

Kepler's third law is a statement of

  1. conservation of energy
  2. conservation of angular momentum
  3. both
  4. neither



2 a. Two satellites are placed in circular orbits. Satellite A is orbiting the Earth, while satellite B orbits the moon. If both orbits have a radius of 7000 km, which satellite has a shorter period? What is the ratio of the satellites' periods?



2 b. Estimate how fast you must throw a baseball to make it go around the Earth at your current altitude. State any assumptions made to get your answer.

 

3 a.

A planet's orbit around the sun is an ellipse. Consider points A and B on the ellipse. How does the centripetal force exerted on the planet at point A compare to the centripetal force exerted on the planet at point B? How about the kinetic energies at A and B? How about angular momenta?

3b.

Two different planets are orbiting the same sun along two different orbits. The red orbit is circular, the blue orbit is elliptical. Compare the speeds of the planet in the blue orbit at points A, B, and E. Compare the speeds of the planet in the red orbit at points C, D and E. The planet in the blue orbit is to be shifted to the red orbit as it passes point E. Does it have to speed up or slow down?

State your reasons for all of your answers.


 



4. Below is a space for your thoughts, including general comments about today's assignment (what seemed impossible, what reading didn't make sense, what we should spend class time on, what was "cool", etc.):




You may change your mind as often as you wish. When you are satisfied with your responses, click the SUBMIT button.

I received no help from anyone on this assignment.