Interactive lab · projectile motion
One clock, two axes that never talk to each other.
Every projectile mistake on the diagnostic comes from letting the axes contaminate each other — using the full launch speed for height, or the horizontal speed for fall time. Fly the model until the independence is obvious, then prove it on numeric problems that recognize the wrong turns.
- Model
- aₓ = 0 · a_y = −g
- Bench
- live trajectory + vector readout
- Practice
- 6 problem types · randomized values
- Feedback
- trap-matched · not just "incorrect"
Objectives: fall time, landing distance, peak height, and air time — all from one resolve-first habit.
- x
- 0 m
- y
- 0 m
- vₓ
- 11.6 m/s
- v_y
- 13.8 m/s
- range
- 32.6 m
- peak
- 9.7 m
vₓ (green) never changes — no horizontal force. v_y (amber) loses 9.8 m/s every second, no matter what vₓ is doing. That independence is the whole model.
Predict first then test it
Two identical balls are launched from the ground at the same speed — one at 30°, one at 60°. Ignoring air resistance, which lands farther away?
Worked example one resolve, three answers
- 01
Model
A ball leaves level ground at v₀ = 20 m/s, 37° above horizontal. No air resistance, so the only force in flight is gravity: aₓ = 0, a_y = −9.8 m/s². We want air time T, range R, and peak height H.
Practice desk 0/6 solved
Numeric answers, checked with a ±2% tolerance — sig figs won't bite you. Wrong answers are matched against the known wrong paths, so the feedback names the actual mistake, not just "incorrect."
A ball is launched horizontally at 20 m/s from a cliff 34 m above level ground. How long is it in the air? (g = 9.8 m/s², ignore air resistance)
next Pressure-test the model
The lab builds the model in a quiet room. The ladder and the diagnostic test whether it survives contact with trap-heavy problems.