1. Draw the path the Earth takes as it travels around the sun. Draw and label the velocity and gravity force vectors. How is the cartoon version different from the scale version?

2. What happens to the path of the Earth when you turn off gravity?

3. If you increase the mass of the Sun, what happens to the Earth?

4. If you decrease the mass of the Sun, what happens to the Earth?

5. Click on the Earth/satellite button. Increase the speed of the satellite (change the magnitude of the velocity vector). What happens? Explain.

6. Decrease the speed of the satellite. What happens? Explain.

7. Move the satellite. Describe what happens. Can you make a stable orbit further from the Earth? How did you do it?

8. Change the mass of the satellite only. How do the velocity and force vectors change? Will this change the orbit of the satellite? Why or Why not? Explain what happens.

9. The mass of the moon is 7.35x1022kg and the mass of the earth is 5.97x1024kg. The moon's orbit distance is 3.84x108m. Use Newton's law of gravitation to figure out the following question. What is the gravitational force on the moon by the earth? What is the gravitational force of the earth on the moon?