Intro to Space Systems Exploration Pretest

Front

What happens to Earth if the Sun's gravity disappears?

Back

Earth would stop orbiting the Sun and begin moving in a straight line.

Front

What does it mean when we see less and less of the Moon each night?

Back

It means the Moon is in its waning phases.

Front

What two forces keep the planets in their orbits around the sun?

Back

Gravity and inertia.

Front

What term describes the time it takes for Earth to complete one circle around the sun?

Back

Revolution.

Front

When will the gravity between two objects be the least?

Back

When the masses of both objects are small and the objects are far apart.

Front

What is the force that pulls objects toward each other?

Back

Gravity.

Front

What is inertia?

Back

Inertia is the tendency of an object to resist changes in its state of motion.

Front

What is the difference between rotation and revolution?

Back

Rotation is when an object spins on its axis, while revolution is when an object orbits around another object.

Front

What is the average distance from the Earth to the Sun?

Back

About 93 million miles (150 million kilometers).

Front

What is a lunar phase?

Back

A lunar phase is the appearance of the Moon as seen from Earth, which changes as the Moon orbits the Earth.