# Momentum Principle and Energy Principle Problem

• Oct 1st 2009, 06:03 PM
Hellacious D
Momentum Principle and Energy Principle Problem
You will need to use the Momentum Principle to do the first part of this problem, and the Energy Principle to do the second part.

A satellite of mass 4500 kg orbits the Earth in a circular orbit of radius of 9.2x10^6 meters http://www.webassign.net/images/multiply.gif[/IMG] 106[/COLOR] m (this is above the Earth's atmosphere).The mass of the Earth is 6.0 http://www.webassign.net/images/multiply.gif 1024 kg.
What is the speed of the satellite?
v = 1 m/s
What is the minimum amount of energy required to move the satellite from this orbit to a location very far away from the Earth?
energy = 2 J

Not really sure what to do here, I feel as though I need more information to work this. Help is much appreciated.
• Oct 1st 2009, 07:24 PM
aidan
Quote:

Originally Posted by Hellacious D
You will need to use the Momentum Principle to do the first part of this problem, and the Energy Principle to do the second part.

A satellite of mass 4500 kg orbits the Earth in a circular orbit of radius of 9.2 http://www.webassign.net/images/multiply.gif 106 m (this is above the Earth's atmosphere).The mass of the Earth is 6.0 http://www.webassign.net/images/multiply.gif 1024 kg.
What is the speed of the satellite?
v = 1 m/s
What is the minimum amount of energy required to move the satellite from this orbit to a location very far away from the Earth?
energy = 2 J

Not really sure what to do here, I feel as though I need more information to work this. Help is much appreciated.

Need some clarification:
Quote:

in a circular orbit of radius of 9.2 http://www.webassign.net/images/multiply.gif 106 m (this is above the Earth's atmosphere

9.2x106 = 975.2 and I assume the m stands for miles even though mass is metric and joules is metric.
When you say atmosphere, the exosphere is about 300 miles up. Is the 975 miles in ADDITION to the 300 miles or is the 975 miles above the surface of the earth?
• Oct 1st 2009, 07:50 PM
Hellacious D
Sorry, it's 9.2E6 meters

and 6E24 kg.

idk why it gives energy and velocity... 1 and 2 respectively for those is wrong
• Oct 4th 2009, 01:42 AM
Quote:

Originally Posted by Hellacious D
You will need to use the Momentum Principle to do the first part of this problem, and the Energy Principle to do the second part.

A satellite of mass 4500 kg orbits the Earth in a circular orbit of radius of 9.2x10^6 meters http://www.webassign.net/images/multiply.gif[/IMG] 106[/color] m (this is above the Earth's atmosphere).The mass of the Earth is 6.0 http://www.webassign.net/images/multiply.gif 1024 kg.
What is the speed of the satellite?
v = 1 m/s
What is the minimum amount of energy required to move the satellite from this orbit to a location very far away from the Earth?
energy = 2 J

Not really sure what to do here, I feel as though I need more information to work this. Help is much appreciated.

Are you sure the speed of the satelite is 1m/s . I doubt if its possible .

For (1) , Have its gravitational attraction between the earth and the satelite equals the centripetal force of the satelite . Then solve for v .

ie (GMeMs)(R^2)=(Msv^2)(R) , this R is the orbit of sat .