Mistake Master
Mistake Master · AP Physics 2 · Unit 10 · Step-Through Animation
Energy With a Sign On It
You'll learnwhy the charge signs stay inside U = kq₁q₂/r, what a negative energy actually tells you, and how to total three charges without counting anything twice.
A proton and an electron store energy in their arrangement, and the number comes out negative. That minus is not a mistake: it is the difference between a pair that is bound and a pair that flies apart. Ten short steps; press Next for each one.
signed charges into U = kq₁q₂/r · three charges make three pairs
Before you start
What you're looking at
Charges, and the energy stored in their arrangement. Violet marks a bound pair's energy; red marks a pair that would fly apart.
The question
What does the sign of a potential energy tell you, and how many terms do three charges make?
Step 1 / 10