Imagine for a Minute That the Moon Is Held in Its

question 34

Short Answer

Imagine for a minute that the Moon is held in its orbit about the Earth by electrical forces rather than by gravitation. What electrical charges −Q on the Earth and +Q on the Moon are necessary to hold the Moon in a circular orbit with a period of 27.3 days? The Earth-Moon distance is 384,000 km and the mass of the Moon is 7.35 × 10²² kg.

---

Definitions:

Equivalent Annual Annuity

A method used in financial analysis to compare the profitability of investments with differing durations by converting values into equal annual payments.

WACC

Weighted Average Cost of Capital; a calculation of a firm's cost of capital in which each category of capital is proportionally weighted.

Discounted Payback

A capital budgeting procedure that calculates the time required to break even from an investment, accounting for the time value of money.

Cash Flow

The net amount of cash being transferred into and out of a business, a key indicator of financial health.