Use unfamiliar values and changed assumptions to defend a physical conclusion.
These 14 original public cases sample the current physics sequence. Ten require calculations and four require an evidence-based choice. Together they sample motion, forces, conservation, rotation, fluids, thermal physics, waves, fields/circuits and modern evidence. They do not cover every course objective. Explain your reasoning before recording a response; a matching number or choice does not automatically grade the explanation.
First and latest responses, up to three attempts and known feedback exposure are retained in science backups. Explanation drafts remain editable after feedback. Returning later or importing an older backup does not make an exposed case fresh. Keys are inspectable in this static application: this is practice, not a secure exam or independent mastery assessment.
0/14 cases attempted; 0/14 first responses match the keys. Unattempted cases supply no evidence. These counts do not change lesson completion or award course mastery.
A cart moves from x = −2 m to +7 m, then to +3 m in 5 s total. What is its average speed?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
A 0.50 kg cart experiences +0.80 N drive and −0.30 N resistance. What is its acceleration?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
A 0.40 kg cart enters braking at 0.80 m/s. Constant opposing force is 0.20 N. What stopping distance follows, ignoring rotation and other losses?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
A 0.20 kg cart at +1.2 m/s sticks to a stationary 0.40 kg cart. Neglect external impulse. What is their common velocity?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
A virtual isolated heater transfers 150 J into 20 g water with c = 4.0 J/(g K) and a cup of heat capacity 20 J/K. What common temperature rise follows?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
An ideal 6 V source drives a single 12 Ω resistor. What thermal power is dissipated?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
A wave has frequency 5 Hz and wavelength 0.40 m. What phase speed does the simple periodic-wave relation give?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
An original ensemble has 2400 parent nuclei and a 30 s half-life. What expected number remains after 90 s?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
A charged particle moves in a uniform magnetic field with velocity perpendicular to the field, with no electric field or other force. Which classical result follows?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
An invented atom has allowed populated levels 2, 5 and 9 eV. A direct transition from 9 to 5 eV emits what photon energy?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
In a one-photon photoelectric model, photon energy is 1.5 eV and the work function is 2.0 eV. What follows when incident power doubles at unchanged frequency?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
A carbon-14 nucleus becomes nitrogen-14 through beta-minus decay. Which additional particles belong in the equation?
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
A massless horizontal lever pivots at its center. A downward 4 N force acts 0.30 m left of the pivot. What downward force 0.20 m right of the pivot gives zero net torque? Both forces are perpendicular to their arms.
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
A 0.30 kg object floats at rest in a liquid with stipulated density 1000 kg/m³. Neglect air buoyancy and surface tension. What liquid volume is displaced, in cm³? Use equal gravitational acceleration for weight and buoyancy.
Explain the mechanism, evidence and assumptions. This saved draft stays editable after feedback; it is not a locked first-attempt explanation and is not automatically graded.
0/3 attempts recorded. No recorded feedback exposure in this notebook.
The rotation and fluid case relationships were checked on 30 October 2026 against torque equilibrium and Archimedes’ principle. Related lesson links provide the other concept sources. All case values and prose are original.
For each response, identify the system boundary, quantities and units, relevant mechanism, assumptions and a limitation. Explain what evidence would change your conclusion. If you revise after feedback, describe the error you repaired. A current explanation draft can reflect later learning and is not a locked record of prior understanding.
A reviewer should examine the explanations alongside the virtual transport-design project and a fresh task with changed evidence. Check calculations, causal reasoning and alternatives separately. Public practice does not establish laboratory technique, independent investigation or AP readiness.
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