Single-problem validation

Passenger in an accelerating elevator

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Passenger in an accelerating elevator

Run one observed attempt for this mechanics model before changing problem scope.

Full validation pack
  1. Run one student on one problem at a time; do not demo the full site first.
  2. Start from the public problem page, then switch to Solve mode before any answer-key exposure.
  3. Record attempt time, finish state, first hesitation checkpoint, first wrong path, and whether the reveal changes their explanation.
  4. Paste the copied Solve-mode attempt snapshot into notes as evidence, but do not treat it as a score or success verdict.
  5. Count the visible corrections or checker recoveries before the student can explain the governing equation in their own words.
  6. Record the exact first-success quote or mark no usable evidence; do not infer clarity from a correct final answer.
  7. Show the tutor the worksheet answer key only after the student attempt, then capture concrete reuse or rejection reasons.

Decision gate

Student task

Solve modeProblemWorksheet

Student can explain why "N = m(g + a)" follows from the diagram state and givens.

Focus checkpoints

  • Choose the upward vertical axis
  • Apply Newton's second law vertically
  • Solve for the scale force
  • Substitute values

Observe for

  • Does the student avoid this trap without prompting: Using N = mg and ignoring the upward acceleration.
  • Which checkpoint caused the first real hesitation or correction?
  • Did the reveal help them explain the equation, or only copy the next algebra line?

Equation-choice spot checks

  • Choose the upward vertical axisWhat feature of the diagram, sign convention, or givens makes "Choose the upward vertical axis" the right next equation?
    Listen for: The elevator accelerates upward, so choosing +y upward makes the acceleration positive.Flag if: Student can only quote "+y = upward" without connecting it to the diagram state or givens.
  • Apply Newton's second law verticallyWhat feature of the diagram, sign convention, or givens makes "Apply Newton's second law vertically" the right next equation?
    Listen for: Normal force is positive and weight is negative on the chosen axis. The net upward force equals ma.Flag if: Using N = mg and ignoring the upward acceleration.
  • Solve for the scale forceWhat feature of the diagram, sign convention, or givens makes "Solve for the scale force" the right next equation?
    Listen for: Rearranging the vertical equation shows the scale must support weight and provide the extra upward acceleration.Flag if: Subtracting ma from mg for an upward-accelerating elevator.; Reporting 65 kg as the scale reading instead of converting the force model to newtons.
  • Substitute valuesWhat feature of the diagram, sign convention, or givens makes "Substitute values" the right next equation?
    Listen for: The upward acceleration makes the scale reading larger than the passenger's weight. The scale reads about 7.5e2 N.Flag if: Student can only quote "N = 65(9.8 + 1.8) = 754 N" without connecting it to the diagram state or givens.
  1. Open the Solve-mode link for Passenger in an accelerating elevator and ask the student to restate the target unknown before writing equations.
  2. Ask for the diagram state first: axes, direction assumptions, and the force or motion components they expect to use.
  3. Let the student attempt one scratch line before any checkpoint reveal, then use Check this line only after the attempt.
  4. If they stall, reveal one checkpoint and ask them to say which diagram element or given made that equation necessary.
  5. After the result checkpoint, ask for one sentence explaining why the chosen governing equation was the right model.

Tutor review prompts

  • Would you send /problems/elevator-apparent-weight to a student stuck on this exact problem?
  • Which checkpoint would save you the most explanation time?
  • Which diagram label, assumption, or rubric row feels misleading or too thin?
  • What one change would make this problem page worth reusing in a lesson?

Tutor rubric cues

  • Setup (0 / 1 / 2)Axes, sign convention, model constraints, and linked-motion/origin choices are stated.Score descriptions
    • 0No usable evidence for this row, or the work contradicts "Choose the upward vertical axis".
    • 1Partly correct, but review this row's checkpoint signal: evidence reaches "Choose the upward vertical axis" but is not yet consistent across the row
    • 2Complete row: Axes, sign convention, model constraints, and linked-motion/origin choices are stated.
  • Components (0 / 1 / 2)Resolved components, force directions, normal/friction setup, or velocity split are correct.Score descriptions
    • 0No usable evidence for this row, or the work contradicts "Identify the passenger forces".
    • 1Partly correct, but review this row's checkpoint signal: evidence reaches "Identify the passenger forces" but is not yet consistent across the row
    • 2Complete row: Resolved components, force directions, normal/friction setup, or velocity split are correct.
  • Net-force / governing equation (0 / 1 / 2)The main Newton's law or motion equation uses the right model, signs, and shared variables.Score descriptions
    • 0No usable evidence for this row, or the work contradicts "Apply Newton's second law vertically".
    • 1Partly correct, but review this row's checkpoint signal: Using N = mg and ignoring the upward acceleration.
    • 2Complete row: The main Newton's law or motion equation uses the right model, signs, and shared variables.
    Watch: Using N = mg and ignoring the upward acceleration.
  • Result (0 / 1 / 2)The final rearrangement, numeric value, units, and direction/speed interpretation are correct.Score descriptions
    • 0No usable evidence for this row, or the work contradicts "Solve for the scale force".
    • 1Partly correct, but review this row's checkpoint signal: Subtracting ma from mg for an upward-accelerating elevator.
    • 2Complete row: The final rearrangement, numeric value, units, and direction/speed interpretation are correct.
    Watch: Subtracting ma from mg for an upward-accelerating elevator.; Reporting 65 kg as the scale reading instead of converting the force model to newtons.

Passenger in an accelerating elevator session notes

Capture observed outcomes from real attempts: time, hesitation checkpoint, wrong path, copied Solve-mode snapshot evidence, recovery, equation-choice explanation, first-success evidence, manual tutor row scores, and tutor send-link decision.

Next-fix queue

Use after real attempts: carry only observed time, hesitation, wrong-path, recovery, equation-choice, first-success, manual tutor row-score, or tutor-rejection evidence into the next product slice. The evidence gate flags partial notes before they masquerade as product signals.

No observed attempts yet
Observed sessions: 0Ready for next-fix review: 0Need more observed evidence: 0

Run one single-problem Solve-mode attempt before choosing a product fix or adding another mechanics model.

No observed next fixes yet.

Passenger in an accelerating elevator

Solve modeProblemWorksheetBrief

Focus checkpoints: Choose the upward vertical axis; Apply Newton's second law vertically; Solve for the scale force; Substitute values

Tutor row-score template: Setup ___ / 2; Components ___ / 2; Net-force / governing equation ___ / 2; Result ___ / 2; reteach cue: ___

Seed from Solve snapshotPaste a copied Solve-mode attempt snapshot. Only filled starter fields are imported; placeholder blanks stay missing evidence.
Evidence checklistNeed all five evidence groups before this note can drive next-fix review.
  • Missingattempt time / finish stateAttempt time and finish state
  • Missingequation-choice evidenceEquation-choice explanation
  • Missingfirst-success quote or verdictFirst success-test evidence
  • Missingscratch, checker, or reveal evidenceWrong path or scratch line / Solve attempt snapshot evidence / Corrections before recovery / Reveal outcome
  • Missingmanual tutor row, tutor decision, or next-fix cueTutor row scores and reteach cue / Tutor send-link decision / Next fix before adding problems
Manual row-score summaryEnter observed 0/1/2 row scores to summarize manual tutor evidence.Blank row-score starters stay out of totals and do not count as grading.
Manual row-score helper0/1/2 rows from the existing tutor rubric. Blank starters do not count as evidence.
  • Setup ___ / 2Axes, sign convention, model constraints, and linked-motion/origin choices are stated.0: No usable evidence for this row, or the work contradicts "Choose the upward vertical axis". | 1: Partly correct, but review this row's checkpoint signal: evidence reaches "Choose the upward vertical axis" but is not yet consistent across the row | 2: Complete row: Axes, sign convention, model constraints, and linked-motion/origin choices are stated.
  • Components ___ / 2Resolved components, force directions, normal/friction setup, or velocity split are correct.0: No usable evidence for this row, or the work contradicts "Identify the passenger forces". | 1: Partly correct, but review this row's checkpoint signal: evidence reaches "Identify the passenger forces" but is not yet consistent across the row | 2: Complete row: Resolved components, force directions, normal/friction setup, or velocity split are correct.
  • Net-force / governing equation ___ / 2The main Newton's law or motion equation uses the right model, signs, and shared variables.0: No usable evidence for this row, or the work contradicts "Apply Newton's second law vertically". | 1: Partly correct, but review this row's checkpoint signal: Using N = mg and ignoring the upward acceleration. | 2: Complete row: The main Newton's law or motion equation uses the right model, signs, and shared variables.Watch: Using N = mg and ignoring the upward acceleration.
  • Result ___ / 2The final rearrangement, numeric value, units, and direction/speed interpretation are correct.0: No usable evidence for this row, or the work contradicts "Solve for the scale force". | 1: Partly correct, but review this row's checkpoint signal: Subtracting ma from mg for an upward-accelerating elevator. | 2: Complete row: The final rearrangement, numeric value, units, and direction/speed interpretation are correct.Watch: Subtracting ma from mg for an upward-accelerating elevator.; Reporting 65 kg as the scale reading instead of converting the force model to newtons.