Chapter 21, The Moon and Mercury: Comparing Airless Worlds Video Solutions, Foundations of Astronomy

01:20

Problem 1

Calculate the escape velocity of the moon from its mass and diameter. (Hint: See Chapter 5.)

Garrett Bess

Numerade Educator

01:15

Problem 2

Why do small planets cool faster than large planets? Compare surface area to volume. Why is that comparison important?

Sanjeev Kumar

Numerade Educator

04:03

Problem 3

The smallest detail visible through Earth-based telescopes is about 1 arc second in diameter. What linear size is this on the moon? (Hint:
Use the small-angle formula, Chapter $3 . .$

Daniel Alva

Numerade Educator

02:33

The trenches where Earth's seafloor slips downward are $1 \mathrm{km}$ or less wide. Could Earth-based telescopes resolve such features on the moon? Why can you be sure that such features are not present on the moon?

Rodger Claar

Numerade Educator

01:31

Problem 5

The Apollo command module orbited the moon about $100 \mathrm{km}$ above the surface. What was its orbital period? (Hint: See Chapter 5.)

Ajay Singhal

Numerade Educator

01:29

Problem 6

From a distance of $100 \mathrm{km}$ above the surface of the moon, what is the angular diameter of an astronaut in a spacesuit? Could someone have seen the astronauts from the command module? (Hint: Use the small angle formula, Chapter $3 . .$

Eleanor Johnson

Numerade Educator

01:40

Problem 7

If you transmitted radio signals to Mercury when it was closest to Earth and waited to hear the radar echo, how long would you wait?

Lottie Adams

Numerade Educator

01:06

Problem 8

Suppose you sent a spacecraft to land on Mercury, and it transmitted radio signals to Earth at a wavelength of $10 \mathrm{cm} .$ If you saw Mercury at its greatest angular distance west of the sun, to what wavelength would you have to tune your radio telescope to detect the signals? (Hints: See Celestial Profile 4 and the section on the Doppler shift in Chapter $7 .)$