Two satellites A and B orbit the Earth in the same plane. Their masses are 7 m and 8 m, respectively, and their radii 5 r and 8 r, respectively. 8 r 5 r B 8 m A 7 m What is the ratio of their orbital speeds? 1. vB vA = r 8 5 2. vB vA = r 5 7 3. vB vA = r 8 7 4. None of these 5. vB vA = r 7

Explanation:

Given  

Satellite A has a mass of 7 m and at a radius of 5 r

Satellite B has a mass of 8 m and at a radius of 8 r

Orbital velocity is the velocity required by a satellite to remain in its orbit

Orbital velocity can be find by equating centripetal force on satellite and Force of gravitation between satellite and Planet

where M=mass of Planet

m=mass of body

r=distance from center of Planet

We can say that orbital velocity is independent of mass of satellite

For satellite A

For satellite B

divide 1 and 2 we get

because it says use -2,0,and 2 for x, we can plug those numbers into the equation. y/4=3/4(-2)+2   y/4= -1 1/2 +2 now to get x by itself, we can multiply each side by 4. y=-6+8 which equals y=2 when x=-2. now you can do the same thing with 0 and 2 as x. you get y=8 when x=0 and y=14 when x=2.

x   |   y

-2 |   2

0   |   8

2   |   14

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