Gravity

Which answer best describes Newton's Law of Universal Gravitation?

• The gravitational pull exerted on an object depends on the length of its orbital path.
• The smaller an object is, the greater the force of gravity it exerts.
• Only the largest object in the universe exerts a constant force that pulls every other object towards it.
• All objects in the universe exert a gravitational force on all other objects.

Why does the Sun not orbit Earth?

• Only celestial objects within ten thousand miles of each other can be brought into another body's orbit
• Earth's mass is less than the Sun's, so it does not have a strong enough gravitational pull to attract the Sun into its orbit.
• Only celestial bodies that emit light, like the Sun, can be the center orbits.
• The Sun has an elliptical orbit, so it cannot orbit Earth, which has a circular orbit.

A student is looking at a model of the solar system noted there is a belt of objects in orbit in between Mars and Jupiter. What are these orbiting objects?

• Comets
• Moons
• Asteroids
• Pluto

A small planet that is close to the Sun will -

• have a strong gravitational pull exerted on it
• pull several smaller planets into its orbit
• have too great a mass to orbit the Sun
• orbit in an elliptical path

Why do planets follow circular orbital paths?

• The force of motion and force of gravity maintain the planets' constant path towards the Sun
• In order to follow an elliptical path, the planet would have to be larger than the Sun
• Planets' masses are too large to be influenced by the gravity of bodies other than the Sun
• Planets lose the ability to move forward over time as they travel such a long distance to orbit the sun

A student noticed that the Moon orbits Earth and wondered why. What aspect of Newton's Law of Universal Gravitation would help answer the student's question?

• The Moon was once part of Earth
• The greater the distance between two objects, the weaker the force
• All objects exert the force of gravity on all other bodies.
• There is no gravity in space

Scientists at NASA have taken pictures of planets being "eaten" by a star. What could have happened to the orbit of the planet?

• The gravity of the planet equals the gravity of the star.
• The planet did not belong to that solar system.
• The force of gravity of the star is less than the forward motion of the planet.
• The force of gravity of the star is greater than the forward motion of the planet

A student was challenged to put the planets of the solar system in order by the amount of the force of gravity of each planet. What planet should be listed as having the greatest gravitational force?

• Jupiter
• Earth
• The Sun
• Uranus

What is the massive object the planets of our solar system orbit?

• Venus
• Earth
• Jupiter
• The Sun

What is an orbiting object that is not a planet in which a student could include in a model of the solar system?

• Neptune
• A comet
• The Sun
• A star