Midterm

What does Kepler’s 1st Law state about the planet's orbit?

• The orbit of a planet is an ellipse with the Sun at one of the two foci.

• The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit.

• The line joining a planet and the Sun sweeps out equal areas during equal intervals of time.

• Planets move in circular orbits with uniform speed.

Kepler’s 2nd Law is called: Equal Areas in Equal Time. What does Kepler’s 2nd Law state?

• The planet is moving fastest from interval A to B.

• The planet is moving at the same speed in all intervals.

The barycenter between two objects in space is always closest to the object that has....

• a greater mass

• a greater density

Earth’s axis points in different directions, this will change our North Stars (Polaris to Vega). What Earth motion is this?

• Revolution

• Rotation

• Nutation

• Precession

What motion describes Earth’s wobble?

• Revolution

• Rotation

• Nutation

• Precession

Earth is __________ on its axis. This is the reason for seasons!

If the Earth was NOT tilted, like the image below... What would happen to Earth’s season?

• The seasons would be more extreme.
• There would be two seasons instead of four.
• The seasons would be shorter in duration.
• There would be no seasons.

How long does Earth take to do the following motions.... a. Rotate on its axis: __________ b. Revolve around the sun: __________

• a. 24 hours

  b. 365.25 days

• a. 365.25 days

  b. 24 days

• a. 12 hours

  b. 365 days

Why are the seasons DIFFERENT in the Northern and Southern hemispheres?

• The Sun gives off more heat in the summer and less heat in the winter.

• Earth is farther from the Sun in winter and closer to the Sun in summer.

• With more clouds in the winter, less sunlight can reach the surface of Earth.

• Since Earth is tilted on its axis, heat from the Sun gets distributed unequally.

Circle one: Which nuclear process powers the sun? Fusion or Fission

• Fusion

• Fission