Mistake Master
Mistake Master · AP Precalculus · Unit 4 · Step-Through Animation
Two Throttles, One Moving Point
You'll learnto track an object's motion by its horizontal and vertical positions separately.
A moving point in the plane runs on two independent throttles: one sets how it drifts left and right, the other how it rises and falls, and time drives both. Read them apart and the puzzles dissolve — at the top of a leap the vertical throttle reads zero while the horizontal one keeps right on going.
Unit 4 is not assessed on the AP exam; schools include it where local requirements ask.
arrowheads show the direction of travel
Before you start
What you're looking at
A moving object with three displays: horizontal position over time, vertical position over time, and the combined path.
The question
At this instant, what is each coordinate doing on its own?
Watch for
At the top of a projectile's arc: vertical rate zero, horizontal rate not zero, total motion not stopped.
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