Circular orbit VS Elliptical orbit? Differences?

1. Jul 22, 2009

graphicer89

Circular orbit VS Elliptical orbit?? Differences?

1. The problem statement, all variables and given/known data
Hi im trying to understand some questions about Space and man made satellites...i would really appreciate it if someone could help me out thanks......also i included an extra question about the theory of relativity if you can help me out i would appreciate it....

6) What conditions must be met if a man made satellite is to attain a CIRCULAR ORBIT around the earth? ( choose as many as apply)
A) It must be launched with a tangential speed of 0
B) It must be launched with a tangential speed of 8 km/s
C) It must be launched with a tangential speed greater than 8 km/s
D)It must be launched horizontally at a distance over 150 km above the earth
E) It must be launched vertically with a speed of 8 km/s

4) What conditions must be met if a man made satellite is to attain an ELLIPTICAL ORBIT around the earth? (choose as many as apply)
A) It must be launched with a tangential speed of 0
B) It must be launched with a tangential speed of 8 km/s
C) It must be launched with a tangential speed greater than 8 km/s
D)It must be launched horizontally at a distance over 150 km above the earth
E) It must be launched vertically with a speed of 8 km/s

Belinda takes a trip in a rocket ship that travels at near light speed of her twin Melinda stays at home. Which of the following statements is true?
A) When Belinda arrives back at earth, Melinda will be much older than Belinda because from Belindas frame of reference on the rocket,time in Melindas frame of reference was passing slowly.
B) When Belinda arrives back on earth Melinda will be much older than Belinda because Belindas frame of reference on the rocket is not an inertial reference frame.

2. Jul 22, 2009

tiny-tim

Welcome to PF!

Hi graphicer89! Welcome to PF!

Show us what you think (with reasons), and where you're stuck, and then we'll know how to help!

3. Jul 22, 2009

graphicer89

Re: Circular orbit VS Elliptical orbit?? Differences?

Well the questions about Belinda i think its A because Belinda (THe one who went to space ) her traveling at the speed of light made time for her to pass slowly but i am not sure though....the INERTIAL REFERENCE FRAME on the second one throws me offf....but talking about the first 2 i think the 6 i think is B and E because it falls around the earth so it has to be less than 11. ? of the escape speed.....and number 4 i think C and D because that one is like an oval ..it rotates around the earth and keeps going pass the earth...but what do you think??