Start learning →

NCEA Level 3 Newton's Law of Gravitation — practice questions

Explore 12 free Newton's Law of Gravitation questions in NCEA Level 3 Physics. Open each question or exercise to read its content, reference answers and available explanation.

Practise Newton's Law of Gravitation with Quill →

Newton's Law of Gravitation questions and exercises with answers

Showing questions 1–12 of 12.

What does Kepler's first law state about a planet's orbit around the sun?Read the answer and worked solution →What names are given to a planet's closest and farthest points from the sun in its orbit?Read the answer and worked solution →How is the eccentricity of an ellipse calculated?Read the answer and worked solution →Before Kepler, Copernicus, and Galileo, the Ptolemaic model placed which body at the center of the solar system?Read the answer and worked solution →Why does the moon not trace a perfectly smooth circle around the sun?Read the answer and worked solution →Who first measured the gravitational constant G experimentally, and when?Read the answer and worked solution →Earth's radius is 6.37 x 10^6 m, and g at its surface is about 9.8 m/s^2. Using G = 6.673 x 10^-11 N.m^2/kg^2, what is Earth's mass?Read the answer and worked solution →Using G = 6.673 x 10^-11 N.m^2/kg^2, what is the gravitational force between two 60.0 kg people sitting 100 m apart?Read the answer and worked solution →Mercury orbits the sun with a period of 88.0 days at an average radius of 5.791 x 10^10 m. Using r^3/T^2 = GM/(4 pi^2), what is the mass of the sun?Read the answer and worked solution →Earth orbits the sun at 1.496 x 10^8 km, taking one year. Neptune orbits at 4.490 x 10^9 km. About how many Earth years does Neptune take to complete one orbit?Read the answer and worked solution →A moon's orbital focal point sits 50,000 km from the center of its elliptical orbit, and the orbit's eccentricity is 0.25. What is the length of the semi-major axis?Read the answer and worked solution →Earth's closest approach to the sun is 1.47 x 10^8 km, and its farthest distance is 1.52 x 10^8 km. What is the area enclosed by Earth's orbit?Read the answer and worked solution →

Worked practice questions

What does Kepler's first law state about a planet's orbit around the sun?

  1. It is an ellipse with the sun at one focus
  2. It is a perfect circle centered on the sun
  3. It is an ellipse with the sun at its center
  4. It is a spiral that slowly moves outward
Show answer and solution

Correct answer: A. It is an ellipse with the sun at one focus

1. Kepler's first law describes the shape of every planet's orbit. 2. That shape is an ellipse, not a circle, and the sun sits at one of its two foci rather than at its center. 3. A circle only appears as the special case where the ellipse's eccentricity is zero. _Source: OpenStax Physics (CC BY 4.0), Ch 7 "Newton's Law of Gravitation", section 7.1 Kepler's Laws of Planetary Motion_

Open this question →

What names are given to a planet's closest and farthest points from the sun in its orbit?

  1. Eccentricity (closest) and focus (farthest)
  2. Aphelion (closest) and perihelion (farthest)
  3. Apogee (closest) and perigee (farthest)
  4. Perihelion (closest) and aphelion (farthest)
Show answer and solution

Correct answer: D. Perihelion (closest) and aphelion (farthest)

1. The closest approach to the sun is named perihelion. 2. The farthest distance from the sun is named aphelion. 3. Apogee and perigee are the equivalent terms used for orbits around Earth instead of the sun. _Source: OpenStax Physics (CC BY 4.0), Ch 7 "Newton's Law of Gravitation", section 7.1 Kepler's Laws of Planetary Motion_

Open this question →

How is the eccentricity of an ellipse calculated?

  1. The focus-to-center distance divided by the semi-major axis
  2. The semi-major axis divided by the focus-to-center distance
  3. The semi-major axis multiplied by the semi-minor axis
  4. The semi-minor axis divided by the semi-major axis
Show answer and solution

Correct answer: A. The focus-to-center distance divided by the semi-major axis

1. Eccentricity e is defined as e = f / a. 2. Here f is the distance from the ellipse's center to a focus, and a is the semi-major axis. 3. An eccentricity of zero, where the focus sits at the center, describes a circle. _Source: OpenStax Physics (CC BY 4.0), Ch 7 "Newton's Law of Gravitation", section 7.1 Kepler's Laws of Planetary Motion_

Open this question →

How to practise

  1. Choose a Newton's Law of Gravitation question and try to work out your answer.
  2. Open the question to check the correct answer and read its worked solution.
  3. Continue in the app for bite-sized lessons, explanations and review with Quill. You can start without creating an account.

More Physics topics

Circular and Rotational Motion