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HomeConcept libraryGravity and Orbits

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Follow the authored sequence, or switch to recap mode for a faster review of the same path.

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Starter track5 concepts3 checkpoints135 min

Gravity and Orbits

Not started

Start with one source mass creating a field and potential well, then use that same gravity model to explain circular speed, orbital periods, and the escape threshold.

Use this track when gravity, orbit speed, orbital period, and escape still feel like separate formulas. The path stays inside one bounded gravity story: source mass sets the inward field, the same source creates the potential well, circular orbit balance fixes sideways speed and year length, and escape finishes by asking when the motion stops being bound at all.

Inverse-square fieldPotential wellCircular-year timingEscape threshold

Entry diagnostic

Decide where to enter this path without opening a second testing system.

Reuse the gravity-fields quick test and the existing field-to-potential checkpoint to decide whether to start from the source-mass field basics or jump straight into circular-orbit balance.

Review prerequisite first0 / 2 probes ready

Check the gravity bridge before you enter orbits

Review prerequisite first

Motion and Circular Motion is the authored prerequisite for Gravity and Orbits. Vectors and Components opens this track and sets up the rest of the path. Nothing is hard-gated here; this is simply the clearest setup before the track opens.

Uses the same local-first quick tests, checkpoint challenges, and track history already saved in this browser.

Start Motion and Circular Motion prerequisite trackBegin with Gravitational Fields
  1. Quick testNot started4 questions

    Gravity-fields quick test

    Check whether inward field direction, inverse-square drop, and source-versus-probe roles are already stable.

    No saved quick-test result yet.

    Gravity fields
    Open Gravitational Fields quick test
  2. ChallengeNot started8 checks

    Field-to-potential checkpoint

    Use the existing doubled-distance challenge to verify that the field and potential ratios still stay connected on one gravity setup.

    No saved checkpoint attempt yet.

    Gravity potential
    Open Half the potential, quarter the field

Why this order

The sequence is authored to keep the model honest.

Gravitational Fields comes first because the orbit and energy ideas are harder to trust if the source-field picture is still fuzzy. Gravitational Potential and Potential Energy keeps the same one-mass model while turning the field into a well-depth story, Circular Orbits and Orbital Speed uses that same inward pull for stable sideways motion, Kepler's Third Law and Orbital Periods turns the circular case into honest year-length comparisons, and Escape Velocity closes by showing what changes when the launch is no longer bound.

Shared concept pages

Each step opens the same simulation-first framework.

Compare mode, prediction mode, quick test, worked examples, guided overlays, challenge mode, and read-next cues stay on the concept pages. The track only decides the guided order and the next recommended stop.

Guided path

Follow the concepts and checkpoint moments in order.

Checkpoint cards reuse the authored challenge entries already living on the concept pages.

  1. 1Not startedMastery: NewStart here

    Gravitational Fields

    See how one source mass creates an inward gravitational field, how source mass and distance set the field strength, and how a probe mass turns that field into force without changing the field itself.

    Start here before moving into Gravitational Potential and Potential Energy.

    MechanicsIntro25 min
    Start concept
  2. 2Not startedMastery: New

    Gravitational Potential and Potential Energy

    See one source mass create a negative potential well, compare how potential and potential energy change with distance, and connect the downhill slope of phi to the gravitational field on the same live model.

    Builds on Gravitational Fields before setting up Circular Orbits and Orbital Speed.

    MechanicsIntro25 min
    Open concept
  3. Checkpoint 1LockedNot started

    Field-to-potential checkpoint

    Lock in the doubled-distance case where the potential well becomes half as deep while the field falls to one quarter before orbit balance takes over.

    Finish Gravitational Potential and Potential Energy first. This checkpoint ties together Gravity fields and Gravity potential through Half the potential, quarter the field.

    Pause here after Gravitational Potential and Potential Energy before moving into Circular Orbits and Orbital Speed.

    Gravity fieldsGravity potential8 checksCoreGraph-linkedGuided start
    Return to Gravity potentialOpen concept
  4. 3Not startedMastery: New

    Circular Orbits and Orbital Speed

    See why a circular orbit needs the right sideways speed, how gravity supplies the centripetal acceleration, and how source mass and radius together set orbital speed and period on one bounded live model.

    Builds on Gravitational Potential and Potential Energy before setting up Kepler's Third Law and Orbital Periods.

    MechanicsIntermediate30 min
    Open concept
  5. 4Not startedMastery: New

    Kepler's Third Law and Orbital Periods

    Compare circular orbits around one source mass and see why larger orbits take longer: the path is longer, the circular speed is lower, and the same live model makes the period law visible without hiding the gravity-speed link.

    Builds on Circular Orbits and Orbital Speed before setting up Escape Velocity.

    MechanicsIntermediate25 min
    Open concept
  6. Checkpoint 2LockedNot started

    Circular-year checkpoint

    Keep the source mass matched, then compare the inner and outer circular years honestly so the wider orbit stays slower and takes longer.

    Finish Kepler's Third Law and Orbital Periods first. This checkpoint ties together Orbital speed and Orbital periods through Inner year vs outer year.

    Pause here after Kepler's Third Law and Orbital Periods before moving into Escape Velocity.

    Orbital speedOrbital periods12 checksStretchCompareGraph-linkedGuided start
    Return to Orbital periodsOpen concept
  7. 5Not startedMastery: New

    Escape Velocity

    Launch outward from one bounded gravity source and see how source mass, launch radius, and total specific energy decide whether the object escapes or eventually returns.

    Capstone step after Kepler's Third Law and Orbital Periods.

    MechanicsIntermediate30 min
    Open concept
  8. Checkpoint 3LockedNot started

    Escape-threshold checkpoint

    Finish the track by separating the last bound launch from the threshold case where the turnaround disappears and the motion is no longer confined to the circular-year story.

    Finish Escape Velocity first. This checkpoint ties together Gravity potential, Orbital speed, Orbital periods, and Escape speed through Remove the finite turnaround.

    Final checkpoint that closes the authored track after Escape Velocity.

    Gravity potentialOrbital speedOrbital periodsEscape speed8 checksCoreGraph-linkedGuided start
    Return to Escape speedOpen concept