John Burk

@RobSpencer1 Could you use an online strobe website like #0" target="_blank" rel="nofollow noopener">moodlight.org/#0

#ITeachPhysics I'm ISO an iPad app with an adjustable strobe (0hz-30hz will do). My district just bought us iPads to replace phone apps that we use all the time. I can't find an app that works on an iPad. Another option would be a $10-15 adjustable freq strobe light. Suggestions?

@RobSpencer1 I think you could build a simple react native app to do this. Here's what I was able to put together with bolt.new in a few minutes: bolt.new/~/sb1-6hmsrj43.

#iteachphysics I am in search of a strobe light that I can mount on the ceiling (maybe battery powered) and control the frequency (up to 30 hz) that is inexpensive. Can anyone share some ideas if you have them? Thanks!

@joshgiesbrecht It worked! Thanks!

@joshgiesbrecht Oh, that makes me even more curious to see what 6th grade math looks like in Canada…

@joshgiesbrecht Any chance you’d be willing to share those? I have a 6th grader and am curious what standards get covered in other classrooms…

🎉 We're so thrilled to welcome @pivot_is to the DE family! Learn how Pivot Interactives' phenomena-based learning is revolutionizing science eduction >> bit.ly/3PX8Hbm

It's been a long time in the pipeline...Python in Tychos! Now you can code in either Python or continue to write your simulations using MathJs. Python is the new default, but just change it in the Settings tab.

Python in Tychos...here is the new Language Reference Docs: docs.tychos.org/docs/learn/lan…

@bennettscience How about @gcschmit’s Polar Bears around an Ice Hole: pedagoguepadawan.net/12/polarbearsa…

The sign on top of this convenience store fridge selling beer reads, "Beer Therapy." Another sign of the triumph of the therapeutic.

In a video message, Ukrainian President Volodymyr Zelenskyy called for peace talks with Russia to be “meaningful, fair and without delay” to stop the invasion of his country. Previous rounds of talks have so far been unsuccessful. bit.ly/3KUVq0S

@Jennifer_Manly @ShriramKMurthi OMG - yes. I lose much time to this. Other major headache is lack of partial credit on digital exams. No way to download Ss responses (they'll email csv if asked), AND no way to upload partial credit scores. Yields lots of student panic and email.

@TRegPhysics Vectors—2+2 can be anything between 0 and 4.

@dandersod Have you seen 3blue1brown’s latest? youtube.com/watch?v=-RdOwh… very related to what you are doing and probably accessible to students.

"Fun" hahahaha

In Precalculus we're finding complex roots for polynomials, and while real roots are easier to visualize, complex roots are tough. Here's the function f(x)=x^3+5x^2+11x+15 graphed over the complex plane (L/R real, U/D imag). Can you "see" the roots now? openprocessing.org/sketch/1309032

@thgmansur Hi, sorry. I gave all of these away years ago.

@occam98 Hi! Do you have one more copy? Thanks

I still have ~10 copies of the 7th edition of PSSC Physics, which is an amazing textbook you want to have in your collection. It can be yours for $4.19 in postage. #Iteachphysics

@pricepd @TychosTeam It’s working fine for me when I try to login…

@metabase do you support two-factor authentication?

@brianwfrank @DeltaGPhys Thanks Brian! I love this video.

If a sphere is sliding and rolling across a level track, Ff acts at the point of contact and is opposite the motion of the sphere. If I take the axis of rotation as the pt of contact, then Ff, Fn, and Fg all act through the axis, so the net torque is zero. So how does L change?

@DeltaGPhys @brianwfrank Thanks Josh!

@BriannoColler Thanks so much! Super helpful!

@occam98 So a zero net moment about the contact point doesn't cause zero angular acceleration. It causes r_{G/p} x m a_p + I_p \alpha = 0. Since a_p is not zero and a_p not colinear with r{G/p} when sliding, \alpha is not zero. (fin)