Topic 1.2: Acceleration
Name: _______________________________ Date: _______________
Before We Start: Yesterday's Recap
Yesterday we learned instantaneous velocity. Without looking back: what's the difference between instantaneous and average velocity?
Today's New Concepts
AP CED Alignment: Unit 1, Topic 1.2
Acceleration
- How quickly an object's velocity is changing — the "rate of change" of velocity, the same way velocity is the rate of change of position
- Formula: $a = \dfrac{\Delta v}{\Delta t}$ (change in velocity divided by the time interval)
- Units: meters per second squared (m/s²)
- A vector quantity — direction matters, just like velocity
- Speeding up, slowing down, AND changing direction all count as acceleration — it's not just "getting faster"
Positive, Negative, and Zero Acceleration
- Positive acceleration: velocity is increasing in the positive direction
- Negative acceleration: velocity is decreasing, or increasing in the negative direction (this is sometimes called deceleration, but only when it's slowing something down — negative acceleration doesn't always mean slowing down)
- Zero acceleration: velocity isn't changing at all — constant velocity
Worked Example: A car speeds up from 0 to 60 mph in 4.2 seconds — a common way car ads brag about performance. That number describes acceleration: how quickly the velocity changed, not just the final speed.
A ball thrown straight up is accelerating downward the ENTIRE time it's in the air — even while still moving upward, and even at the exact top when it's momentarily at rest. Gravity never stops pulling down, so the acceleration never becomes zero, only the velocity does (for an instant, at the peak).
Keep This Sheet!
These sheets build into your semester study guide. Keep them in order in a binder or folder — you'll want to flip back through them before quizzes, unit tests, and when AP exam review starts in the spring.