The SOLAR SYSTEMMMMMMMM

Which of these terms describes a force of attraction between two objects that results from their masses?

• aphelion

• gravity

• orbit

• planetesimal

The diagram below shows the effect of mass and distance on the force of gravity. Which configuration will result in the greatest gravitational force?

• small masses far apart

• large masses far apart

• small masses close together

• large masses close together

The distance between objects, along with the masses of the objects, affect the gravitational force between the objects. Which statement is true according to Newton’s law of universal gravitation?

• When the masses of objects increase, gravitational force decreases.

• When distance between objects increases, gravitational force decreases.

• When distance between objects decreases, gravitational force decreases.

• When the masses of objects decrease, the distance between objects decreases.

Which of these choices states Kepler’s first law of planetary motion?

• As a planet moves around its orbit, the planet sweeps out equal areas in equal amounts of time.

• The orbit of a planet or other body around the sun is an ellipse, and the sun is one focus of the ellipse.

• The square of a planet’s orbital period is proportional to the cube of the planet’s mean distance from the sun.

• Gravitational force increases as the mass of an object increases or as the distance between two objects decreases.

Lee performed calculations that showed that the square of a planet’s orbital period is proportional to the cube of the planet’s mean distance from the sun. What did Lee’s calculations demonstrate?

• Newton’s law of universal gravitation

• Kepler’s first law of planetary motion

• Kepler’s second law of planetary motion

• Kepler’s third law of planetary motion

The diagram below shows the orbit of Halley’s comet. Each region has the same area. The comet covers region 1 in 2,313 days. How long does the comet take to cover region 4?

• 13 days

• 48 days

• 578 days

• 2,313 days

Cara is explaining to her sister how the solar system formed. Which description would she use to explain the solar nebula?

• a rotating cloud of dust and gas

• a disk of material surrounding a young star

• a small body from which planets form

• a rocky core surrounded by a deep atmosphere of gas and ice

Which statement is true about gas giants?

• Gas giants formed close to the sun and contain deep, gaseous atmospheres.

• Gas giants have gaseous cores and rocky surfaces because the planets are far from the sun.

• Gas giants contain no rock or metals because the planets are too cold for these materials to condense.

• Gas giants contain ices because these planets formed far enough from the sun that these materials could condense.

Eric is creating a timeline of the formation of the solar system. Which flow chart best describes the formation of the solar system?

• solar nebula ® protostellar disk ® nuclear fusion ® sun ® planetesimals ® planets

• solar nebula ® protostellar disk ® nuclear fusion ® planetesimals ® planets ® sun

• protostellar disk ® nuclear fusion ® sun ® solar nebula ® planetesimals ® planets

• solar nebula ® nuclear fusion ® sun ® planets ® planetesimals ® protostellar disk

Which statement best describes the role of gravity and centripetal force in the motion of planets around the sun?

• Gravity provides the centripetal force that keeps planets in orbit.

• The sun's gravity causes planets to move forward in a straight line.

• A planet's orbit is the result of forward motion and unbalanced forces.

• Centripetal force is an unbalanced force causing planets to move in a circular path.