physics help!

[magice03]

These two problems i have no idea how to do, please help me out.

1)Suppose that a binary star system consists of two stars of equal mass. They are observed to be separated by 300 million kilometers and to take 6.0 Earth years to orbit about a point midway between them. What is the mass of each?


2)What is the apparent weight of a 79 kg astronaut 4100 km from the center of the Moon in a space vehicle moving at constant velocity?

the radius of the moon is 1.74x10^6 m and the mass is 7.35x10^22kg.

thanks in advance.

 

[miniMUNCH]

Dude...

Gravitational Force = G X (m1Xm2) / r^2.... plug and chug.

 

[magice03]

yeah. i know that. but it is definitely more than plug in the numbers.

 

[Moonbeam]

As regards the astronaut, if he is moving at a constant velocity would that imply that he is in orbit. If he were passing by the moon than you would thing that he would accelerate getting closer and deccelerate going away. So if he IS in orbit wouldn't he be weightless?

 

[magice03]

apparently not. I know the answer is somewhere between 22 and 24 N. I just don't know how to get it.

 

[magice03]

never mind. got them both