AP C folks help me I'm stuck. Want to show Ss how to derive formula for exponential q decay in RC circuit. Starting w/ loop eqn: Vc - Vr = 0. But this results in exponent of e being +, not -. What's the justification for starting w/ Vc + Vr = 0 which ends in correct result?

When drawing a FBD for an object on an incline, I encourage Ss to tilt the axes. Some Ss leave the axes and tilt the forces instead. It's technically correct, but hurts my brain. Does anyone know whether drawing it that way would lose points on the APC Mechanics test?

Catch the “stuntman” in Honors Physics today!

Successful projectile motion calculations!

Another take on it (per student demand).

When studying circular motion we watch a video of pilots in which the technique they use to tolerate g’s is described as “like straining while constipated.” This showed up during retrieval practice today.

AP C Ss practiced a question where B-field is changing in the diagram below. S asked how that could happen since no part of the B-field touches the wire. Could not explain the mechanism other than to cite Faraday's Law: changing flux produces emf. Any idea HOW in this case?

I posed a question that resulted in a lot of replies, retweets,and replies to replies and I'm interested in reading all of it. But now I feel like I'm on a scavenger hunt to find all of that. Is there a way to view everything that branches off from an initial tweet easily??

Two days of class to go. Seniors will not be present so only a few (2-4) underclassmen. I hate doing nothing -- boring for them. Any ideas for fun physics stuff with just a few students?

Since ⁦PASCO scientific⁩ doesn’t have merch, I had to improvise for #nerdyshirtfriday thanks to the town of Pasco, Washington.

The perennial 'why can't we just make electrons positive so electron movement and conventional current are the same?' discussion this week. ... and you say....? (not going to prime your brain with what I say 😉). #iteachphysics

Frōhliches Oktoberfest y’all

#iteachphysics community: I have a student who wants to do a physics science fair project. I'm terrible at coming up with these ideas but I feel like I saw a post once that had a whole bunch of suggestions. Can anyone point me in the right direction??

Raced a ring, solid disk, solid sphere (bowling ball), and spherical shell (basketball) and the photo finish was exactly in the same order as predicted by their rotational inertias.

? for AP C E&M teachers: When Ss integrate the Efield for a sphere to get potential difference from infinity, the V at infinity is 0 which makes sense. But if they do it for a cylinder V at infinity is infinity b/c ln(infinity). That doesn't make sense. Thoughts? #iteachphysics

Some bizarre power failure in my school right now. About to teach E&M. Would love to explain what’s happening but I have to clue. Any ideas? #iteachphysics