Earth-orbiting satellites can be used to help study heavenly bodies such as asteroids. Let us first look at some basic orbital characteristics applicable to the motions of satellites, planets, moons, and asteroids.
Go to http://www.fearofphysics.com --> "Visual Physics" --> "Why Satellites Don't Fall"
1. Observe and record what happens to the satellite after inputting data for the following three scenarios:
a. Height = 500 miles
Speed = 0 mph
Animation Detail --> high
Click "Go"
b. Height = 500 miles
Speed = 100 mph
Animation Detail --> high
Click "Go"
c. Height = 500 miles
Speed = 25000 mph (do not input any commas)
Animation Detail --> high
Click "Go"
2. For a satellite at a height of 500 miles, at what speed must the satellite be traveling to achieve a circular orbit? (A score of 100% will tell you that you have achieved a circular orbit).
3. For a satellite at a height of 22,300 miles, at what speed must the satellite be traveling to achieve a circular orbit? (A score of 100% will tell you that you have achieved a circular orbit).
4. For a satellite already in perfect orbit around the Earth, what would happen if:
- the satellite's speed is reduced?
- the satellite's mass is reduced?
5. Using information covered in the satellite activity above and in class discussions, discuss at least three scientific concepts, which are connected to an asteroid's motion around the Sun. Explain how the asteroid (without any means of propulsion) is able to continually maintain its orbit around the Sun.
6. If the asteroid is moving at a constant speed in its orbit, does this also mean it is moving at a constant velocity? Explain your answer.
7. Based on your answer above, is the asteroid accelerating? Explain.
8. What force (or forces) act(s) to hold the asteroid in orbit around the Sun? What direction does the force (or forces) act?
9. This asteroid's motion is affected by many different massive objects. Rank the following in order of increasing influence: the Sun, Mars, Jupiter, and other asteroids. Explain your answer clearly and specify the main determining factors that you based your ranking on.
10. Assume this asteroid has the shape of a sphere. A rock sitting on the surface of the asteroid has a weight of 100 Newtons. What would the weight of this rock be if it were moved to a distance above the surface equal to the radius of the asteroid? Include calculations or the logic used to get your answer. (It may be helpful to draw a picture to better visualize what is going on). How is the mass of the rock affected by its change in position?
11. At some point in its orbit, our asteroid is moving with a speed of 20 kilometers per second. Determine the kinetic energy of the asteroid assuming it has a mass of 1000 kilograms. Be sure your answer is in the correct units of energy. (1 kilometer = 1000 meters; 1 Joule = kg-m2/sec2).
12. If the distance from the Sun varied during our asteroid's orbit, would its kinetic energy change? Explain. Would its potential energy change? Explain. Would the total energy (sum of kinetic and potential energy) of the asteroid change? Explain your answer.