A question answer community on a mission

to share Solutions for all STEM major Problems.

to share Solutions for all STEM major Problems.

Cant find a problem on ToughSTEM?

0

Two moons orbit a planet in nearly circular orbits. Moon A has orbital radius r, and moon B has orbital radius 4r. Moon A takes 20 days to complete one orbit. How long does it take moon B to complete an orbit?

5 days

20 days

80 days

160 days

320 days

Added Sun, 26 Jul '15

Community

1

Add a Comment

Solutions

0

v = sqrt(Gm/R)

omega = v/r is inversely proportional to r^(3/2)

So the planet with 4r radius takes (4r/r)^(3/2) = 8 times the time i.e. 20*days*8

= 160 days

Added Sun, 26 Jul '15

Community

1

Add a Comment

Add Your Solution!

Close

Click here to

Choose An Image

or

Get image from URL

GO

Close

Back

Add Image

Close

What URL would you like to link?

GO

α

β

γ

δ

ϵ

ε

η

ϑ

λ

μ

π

ρ

σ

τ

φ

ψ

ω

Γ

Δ

Θ

Λ

Π

Σ

Φ

Ω

∫

∮

∞

∝

∇

∴

→

↔

⊆

⊂

∀

∃

∈

∉

∪

∩

∅

Copied to Clipboard

Sign Up

to interact with the community. (That's part of how we ensure only good content gets on ToughSTEM)

OR

OR

ToughSTEM is completely free, and its staying that way. Students pay way too much already.

Almost done!

Please **check your email** to finish creating your account!

Welcome to the Club!

Choose a new Display Name

Only letters, numbers, spaces, dashes, and underscores, are allowed. Can not be blank.

Great! You're all set, .

A question answer community on a mission

to share Solutions for all STEM major Problems.

to share Solutions for all STEM major Problems.

Why

The Purpose

The Purpose

How

The Community

The Community

Give Feedback

Tell us suggestions, ideas, and any bugs you find. Help make ToughSTEM even better.