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**Monday**(45 minutes): position-time graphs, learned through facts and a graph-matching exercise. Homework is about position-time graphs.
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**Wednesday**(90 minutes): velocity-time facts and graph-matching exercise; acceleration facts with demos using the PASCO visual accelerometer; demonstrate free-fall acceleration with a motion detector. Homework is about velocity-time graphs.
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**Friday**(90 minutes): motion diagrams with a 10-Hz dot machine; make a position-time graph from the dot machine output; use two slopes of that graph to find an acceleration. Then, two quantitative demonstrations with the projectile launcher and algebraic kinematics. Homework is about the definition of acceleration.
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**Monday**(45 minutes): finish dot machine lab, correct any issues with the first homeworks. Homework is several algebraic kinematics problems.
Then on Wednesday we're moving into equilibrium of forces. (Those of you who have taken my workshops might be confused - for my upperclassmen, I start the year with equilibrium of forces, and

*then*move into kinematics in the style above. But for 3rd formers who are more at home with real inquiry from the beginning of the class, I dive into motion.)
How, you might ask, does this minimal treatment lead to deep understanding?

Well, it only kinda does right away. It's the long-term re-visitation of these concepts, the integration of kinematics into problem solving with other topics, that truly ingrains deep understanding. Yet, my students average a full two points higher than the national average on the AP Physics 1 exam. They're getting kinematics just fine with my approach.

**I use fact sheets, and demand direct reference to the facts on every problem.**

**A big part of why students struggle at first with understanding motion is that they rely on their prior knowledge. I mean, AP physics students are generally at the top of their class. They are used to half-listening in math or science class, then using their natural talent to reach in the direction of an answer or written justification.***

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*Then they're used to using their debate skills to argue why their answer is technically correct and should earn points.*

I don't provide the class with a lot of facts; but those facts get directly to the point of kinematics concepts. And direct reference to these facts will lead students to correct answers and justifications... if the students can be arsed to use them.

Here are the facts. No justification is accepted unless the student has quoted at least one of these facts nearly verbatim. (When there's a numerical or semi-quantitative problem using the constant acceleration equations, those equations are used instead of these facts.)

And yes, really, these facts and a week of experiments/demonstrations/practice is all that's necessary to dive into kinematics. In my next post, I'll explain how I use the acceleration facts with demonstration to stamp out misconceptions.

**Definitions**

Displacement indicates how far an object ends up from its
initial position, regardless of its total distance traveled.

Average velocity is displacement divided by the time
interval over which that displacement occurred.

Instantaneous velocity is how fast an object is moving at a
specific moment in time.

**Position-time graphs**

To determine how far from the detector an object is located,
look at the vertical axis of the position-time graph.

To determine how fast an object is moving, look at the steepness
(i.e. the slope) of the position-time graph.

To determine which way the object is moving, look at which
way the position-time graph is sloped.

A position-time slope like a front slash / means the object
is moving away from the detector.

A position-time slope like a back slash \ means the object
is moving toward the detector.

Instantaneous velocity is found by taking the slope of the
tangent line to a position-time graph

**Velocity-time graphs**

To determine how fast an object is moving, look at the
vertical axis of the velocity-time graph.

To determine which way the object is moving, look at whether
the velocity-time graph is above or below the horizontal axis.

An object is moving away from the detector if the
velocity-time graph is above the horizontal axis.

An object is moving toward the detector if the velocity-time
graph is below the horizontal axis.

To determine how far an object travels, determine the area
between the velocity-time graph and the horizontal axis.

On a velocity-time graph it is not possible to determine how
far from the detector the object is located.

Most everyday motion can be represented with straight
segments on a velocity-time graph.

**Acceleration**

Acceleration tells how much an object’s speed changes in one
second.

When an object speeds up, its acceleration is in the
direction of motion.

When an object slows down, its acceleration is opposite the
direction of motion.

Objects in free fall gain or lose 10 m/s of speed every
second