Two Moons Orbit a Planet in Nearly Circular Orbits

question 28

Multiple Choice

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?

• A)20 days
• B)40 days
• C)80 days
• D)160 days
• E)320 days

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Definitions:

Redeemed

In finance, it refers to the repayment or buyback of a debt or security, such as a bond or a share, usually at the maturity date or beforehand.

Semiannual Interest

Interest that is calculated and paid twice a year on an investment or loan.

Bond Discount

The financial difference that arises when a bond is sold for an amount below its official face value.

Straight-line Method

A technique for determining depreciation or amortization by uniformly distributing the asset’s cost throughout its lifespan.