Assignment 1 – Gravity & Orbital Motion

Name _______

NSCI 103 Assignment 1 – Gravity & Orbital Motion

1. Go to http://www.fearofphysics.com –> “Visual Physics” –> “Why Satellites Don’t Fall”

 

2. Observe what happens to the satellite when you input the following data:

Height = 500 miles

Speed = 0 mph

Animation Detail –> high

Click “Go”

Satellite crashes

Now input the next situations:

Height =500 miles

Speed = 100 mph

Satellite crashes

Height = 500 miles

Speed = 25000 mph (do not input any commas)

Satellite crashes

3. Discuss your observations of motion for a satellite at a height of 500 miles above the earth, moving at a speed of:

· 0 mph

· 100 mph

· 25000 mph

· Satellite crashes on all Speeds

4. 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).

5. Knowing that the Earth has a circumference of about 24,000 miles, how “fast” is someone standing on the equator traveling?

A couple of hints:

– What is the equation for speed?

– How long does it take the Earth to make one complete rotation about its axis?

6. Describe the orbit of a “geostationary” satellite. How is a geostationary satellite useful?

7. Knowing that a geostationary satellite orbits above the Earth’s equator at a height of about 22,240 miles, calculate a geostationary satellite’s speed as it orbits around the Earth (be sure to show your calculations). Then verify and record your answer using the FearOfPhysics website. (Your speed values may differ slightly due to round off errors).

Circumference and radius are related by the following equation:

C = 2 π r

8. Describe how a satellite is able to maintain an orbit around the Earth without constant propulsion. Include what parameters need to be balanced for orbital motion to occur.

9. For a satellite already in perfect orbit around the Earth, what happens if:

– the satellite’s speed is reduced?

– the satellite’s mass is reduced?

10. Draw the “force diagram” (or clearly describe the force diagram) of a satellite that is orbiting the Earth. (You may use the figure on the next page).

Label all forces acting on the satellite with a single arrow (->), and indicate the direction and magnitude of the “net force” with a double arrow (=>).

DO NOT draw any non-forces in your force diagram.

(The magnitude of the force is represented by the length of its arrow).

(Note that “velocity” is not a force; and inertia is not a force).

(Obviously not drawn to scale).