The speed of light is about $1.9 \times 10^{5}$ miles per second. It takes about 500 seconds for light to travel from the sun to Earth. What is the approximate distance between Earth and the sun? Write in scientific notation.

Use the following values, where needed: radius of the Earth = 4000 mi = 6440 km, 1 year (Earth year) = 365 days (Earth days), 1 AU =

$$92.9 \times 10 ^ { 6 }$$

mi=

$$150 \times 10 ^ { 6 } \mathrm { km }$$

. The dwarf planet Pluto has eccentricity e = 0.249 and semimajor axis a = 39.5 AU. Find the perihelion and aphelion distances.

Why does atmospheric pressure decrease as you go higher in altitude on earth?

What do we call the gravitational force between the Earth and your body.

Write down logical representations for the following sentences, suitable for use with Generalized Modus Ponens:

• a. Horses, cows, and pigs are mammals.
• b. An offspring of a horse is a horse.
• c. Bluebeard is a horse.
• d. Bluebeard is Charlie’s parent.
• e. Offspring and parent are inverse relations.
• f. Every mammal has a parent.

Radiant energy from the Sun arrives at Earth with an intensity of $1.5 kW/m^2.$ Making the rough approxima- Sion that all photons are absorbed, find (a) the radiation pressure and (b) the total force experienced by Earth due to this “solar wind.”

John's mass is $65.0 \mathrm{~kg}$ on the earth. Express his U.S. (a) mass and (b) weight $40 \overline{0} 0\ \mathrm{mi}$ above the surface of the earth, where $g=7.85 \mathrm{ft} / \mathrm{s}^2$ ?

Compute the net force on Earth due to the Sun and Moon (b) when the Moon is new.

Applying Ideas How would seasons be different if Earth was not tilted on its axis?

If a star that is 20 light-years from Earth explodes, gravitational waves from the explosion would reach Earth in (a) less than 20 years. (b) 20 years. (c) more than 20 years. (d) None of these.

If a baseball were the size of Earth, about how large would its atoms be?

In this exercise, there are about 4.8 $\times$ 10$^{19}$ ft$^3$ of water on Earth. One cubic foot of water contains about 9.47 $\times$ 10$^{26}$ water molecules. About how many water molecules are there on Earth?

One kg weighs $10$ N on Earth. Would it weigh more or less on the Moon?

Light from the Sun takes approximately $8.3 \mathrm{~min}$ to reach the Earth. During this time interval the Earth has continued to rotate on its axis. How far is the actual direction of the Sun from its image in the sky?