Secant → Tangent Packet A2
Penguin Percy's position is graphed below. Shrink Δt and watch the secant line (orange) turn into the tangent line (dark). Its slope settles down to the instantaneous velocity.
Controls
Readout
Your table
| Δt (s) | Δx/Δt (m/s) |
|---|
Record a row, shrink Δt, record again. What number are you closing in on?
x → v → a Packet A6–A7
Drag the time slider (or drag on any graph). The tangent line on each graph has a slope equal to the value on the graph below it. In Predict mode the bottom graphs are hidden — your scrubbing leaves a trail of slope dots. Sketch the curve in your head, then reveal.
Controls
At this instant
The Area Machine Packet B1, B4
Add up thin rectangles under the curve. Area above the axis counts positive (blue); below counts negative (orange). Crank up the number of rectangles and compare with the exact answer from the Fundamental Theorem of Calculus.
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Result
Rule Drill Packet A3–A5, B2, B5
Type your answer using ^ for powers, * or nothing for multiplication, and functions like sin(2x), e^(3x), ln(x), sqrt(x). For integrals, leave off the + C. Answers are checked numerically, so any correct form counts.
Problem set
Score
Professor Waddles is ready when you are.
Drag Lab: Hank's Parachute Packet C2 · Topic 2.9
Hank the Hamster falls from rest with air resistance. The smooth curve is the exact solution from separation of variables. The dots are a step-by-step simulation that only uses Newton's second law: a = Fnet/m, then vnew = v + aΔt. Shrink the step and the dots land on the curve.
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Results
The math with your numbers
Slice-a-Rod Packet C1 · Topics 2.1, 5.4
A 1.0 m rod is cut into N slices. Each slice has mass dm = λ(x) dx. Add up the slices to get the mass, the center of mass, and the rotational inertia about the axis you choose. More slices → the sum becomes the integral.
Sum of slices vs. the integral
| Quantity | Integral | Sum with N slices | Exact |
|---|
Controls
Hank says: heavier slices are darker. Watch where the center of mass (orange triangle) sits when one end is denser. Then put the axis at the CM — that's the smallest I can get.