HS-PS2-4: Newton's law of gravitation, with Coulomb's law
What students must show for performance expectation HS-PS2-4, with a lesson sequence built on live data, the misconceptions to expect, and assessment questions with answers.
Last updated . Curriculum links last reviewed November 2026.
What students must show
Our summary- Students use mathematical representations of Newton's law of gravitation and Coulomb's law to describe and predict the gravitational and electrostatic forces between objects.
Both number-based and concept-based descriptions of gravitational and electric fields.
Systems of more than two objects.
Our summary, in our own words. Read the official wording.
The three dimensions
High schoolUsing mathematics and computational thinking
Use mathematical representations of phenomena to describe explanations.
PS2.B Types of interactions
Newton's law of gravitation and Coulomb's law describe forces at a distance; fields carry energy through space.
Patterns
Different patterns at each scale can give evidence for causes.
Live tools for this standard
3 toolsLesson sequence
Engage to evaluate- Engage10 min
The ISS is about 420 km up. Ask: is gravity there 0%, 50% or 90% of its surface value? (Close to 90%.)
- Explore25 min
Inverse-square table: g at the surface, at the ISS (about 420 km), at GPS height (20,200 km) and at geostationary height (35,786 km), Measure every distance from the center of the Earth, so add its radius, 6,371 km, to each height.
- Explain20 min
The Weight on other worlds sheet: g = GM / r^2 for the Moon and Mars. Then Coulomb's law: the same inverse-square form, but charges can repel, and the electric force between two protons is about 10^36 times stronger than gravity.
- Elaborate15 min
The Geostationary orbit sheet: work out how high a satellite must be to circle once per day.
- Evaluate15 min
Two-body problems: the Earth and Moon, a satellite and Earth, two charged spheres.
Common misconceptions
3 to watch forGravity is zero in orbit.
At the ISS's height gravity is close to 90% of its surface value.
Calculate it with the station's live height.
Doubling the distance halves the force.
The force falls with the square of the distance: double the distance and the force drops to a quarter.
The inverse-square table.
Gravity and electric forces have nothing in common.
Both are inverse-square forces acting at a distance. Gravity only attracts and is far weaker.
Put the two laws side by side.
Assessment questions
Answers folded awayHS-PS2-4: Newton's law of gravitation, with Coulomb's law · orbitalradar.com/schools/us/standards/hs-ps2-4
- If the distance between two masses triples, the gravitational force becomes:
- One-third as strong
- One-ninth as strong
- Three times stronger
- Which force can push two objects apart?
- Gravitational
- Electrostatic
- Neither
- Find g at the height of the ISS (420 km). Earth's radius is 6,371 km and g at the surface is 9.8 m/s^2.
- Electric forces are far stronger than gravity, so why does gravity rule the solar system?
- Use the satellite directory: for one satellite, work out the gravitational force per kilogram at its height.
Answer key
- One-ninth as strong.
- Electrostatic.
- 9.8 x (6,371 / 6,791)^2, about 8.6 m/s^2.
- Planets and stars are electrically neutral overall, so electric forces cancel, while gravity always adds up.
- g = 9.8 x (6,371 / (6,371 + h))^2, with h in km.
Worksheet
US LetterOne page on US Letter, filled in with live numbers when you open it. Teacher notes and answers included.
The same idea in state standards
Texas, Florida, Georgia- Texas: Physics 5H, IPC 5E
- Florida: SC.912.P.12.4
- Georgia: SP2.e, SP5.a
Related, not equivalent: each state words and groups its standards differently.
More standards pages
High schoolAbout these codes
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Codes are performance expectations of the Next Generation Science Standards*, for example 5-ESS1-2. Each summary is our own wording; follow the link on a standard page for the official text.
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Cite this page
Pick a style, then copy it or download it for your reference manager.Orbital Radar. (2026, November 6). HS-PS2-4: Newton's law of gravitation, with Coulomb's law. Retrieved November 6, 2026, from https://orbitalradar.com/schools/us/standards/hs-ps2-4
“HS-PS2-4: Newton's law of gravitation, with Coulomb's law.” Orbital Radar, 6 Nov. 2026, orbitalradar.com/schools/us/standards/hs-ps2-4. Accessed 6 Nov. 2026.
Orbital Radar (2026) HS-PS2-4: Newton's law of gravitation, with Coulomb's law. Available at: https://orbitalradar.com/schools/us/standards/hs-ps2-4 (Accessed: 6 November 2026).
Orbital Radar. “HS-PS2-4: Newton's law of gravitation, with Coulomb's law.” Last modified November 6, 2026. https://orbitalradar.com/schools/us/standards/hs-ps2-4.
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Live figures change, so keep the date you accessed the page. How to cite Orbital Radar
* Next Generation Science Standards is a registered trademark of WestEd. Neither WestEd nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of this product, and do not endorse it.