In E1/E2 and E4/E5, prepare the component plan or T-chart and record a prediction before launch, then review the remaining responses with the observed flight. Later sections use the full lesson view: record all four worksheet responses and a trial prediction before revealing results. Paper entries record that you chose paper; they do not claim a correct answer.
Play and +0.25 s advance one shared simulation clock. Replay and the slider inspect the recording. Playback speed changes viewing speed only. Help, number entry and browser interruptions pause playback. Resume deliberately.
Use up as positive. Earth g is a positive magnitude, while ay = −9.8 m/s². No wind or drag acts in this course. Equal-height flight symmetry only applies to equal launch/landing elevations. Sprite size does not change the marked point-mass trajectory.
Presentation view enlarges the laboratory and keeps the step controls. It uses the same prediction rules. Save & skip keeps work without marking a section reviewed. Lessons are optional and independently selectable.
STATE OF THE ARCEarth trajectory training