Mistake Master
Mistake Master · AP Physics 1 · Unit 2 · Step-Through Animation
The Point That Ignores the Drama
You'll learnto draw a system boundary and locate its mass-weighted center of mass.
Two unequal masses, one balance point that refuses to sit in the middle. Draw the boundary, weight the average, then blow the system apart — and watch the one point that doesn't care.
SYSTEMS LAB
Before you start
What you're looking at
A 4 kg block at x = −3 m and a 2 kg block at x = +3 m joined by a rod, with a hollow marker at the middle.
The question
Where is this two-block system's center of mass?
Watch for
Keep an eye on the hollow midpoint marker; the mass-weighted balance point refuses to sit there.
What the symbols mean
One color per block by mass, the rod joins them, and the hollow marker at x = 0 is the tempting geometric middle.
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