Gettin’ Real with Centripetal

Check out this dangerous curve near downtown Atlanta (click the picture to embiggen — it’s the loop in the lower right corner). The curve I’m looking at takes traffic toward the southeast, around the curve with all the perfectly placed trees. Drivers have to navigate a really tight turn. Plenty of them don’t believe the signs warning them to slow down to 25 mph.

How fast can you go around that turn safely?

Georgia Performance Standards: SP1g

SP1. Students will analyze the relationships between force, mass, gravity, and the motion of objects. g. Measure and calculate centripetal force.

Kevin Bacon as Physics Demo?

This upcoming year, I’m back into the physics saddle (part time, at least) and the summer blockbuster schedule is supplying me plenty of fodder for my Physics of Superheros course.

Witness this scene from X-Men: First Class. (As I eagerly await the DVD release, you’ll have to settle for this single image)

Sebastian Shaw is a mutant. His power is that he can absorb kinetic energy and “rechannel it into superhuman strength, speed and durability“. In this scene, he’s about to absorb the energy of a hand grenade.

Just for argument’s sake, let’s say that’s a popular WWII grenade, the Mk2. The TNT equivalent for the 57 g of TNT in a Mk2 is 240 kJ. In order for normal Kevin Bacon to store that much energy, he’d have to climb to a height of 340 m*. Dude, that’s a lot of energy.

Shaw is a walking, talking example of the Conservation of Energy Theorem. He is so going into my class.

Physics peeps — suppose Shaw chose to convert the energy to “superhuman strength”, how strong would he be? More to the point, what does “strength” mean in this sense? Should we go with traditional materials measures of strength like tensile or ductile? Or human measures like “can bench press x pounds”?

* Energy is conserved and potential energy is given by PE = mgh




Solving for h gives h = PE/(mg)

h = 240 kJ / [(70 kg)(9.8 m/s²)]

h= 340 m

This falls under Georgia Performance Standard SP3a, “Students will evaluate the forms and transformations of energy. a. Analyze, evaluate, and apply the principle of conservation of energy and measure the components of work-energy theorem by
• describing total energy in a closed system.
• identifying different types of potential energy.
• calculating kinetic energy given mass and velocity.
• relating transformations between potential and kinetic energy.”

Superhero Physics – Deadpool & Momentum

File me under examples of the Conservation of Momentum cause this beats the heck out of pool table physics: Wade Wilson (aka Deadpool) slices a bullet with his sword — and kills 2 gunmen with the pieces. I found this gem approximately 13 minutes into the movie X-Men Origins: Wolverine (2009).

Here comes the pure awesome moment: the bullet halves kill those two gunmen behind Deadpool.

Momentum is conserved. Sweet.

I owe a huge debt to Dr. James Kakalios for the inspiration to teach physics via superhero examples. His book, The Physics of Superheroes, changed my teaching.

Georgia Performance Standards: (Physics) SP3. Students will evaluate the forms and transformations of energy. c. Measure and calculate the vector nature of momentum. e. Demonstrate the factors required to produce a change in momentum.

Physics Day @ Six Flags

supermanuflogo1I’m taking my students to Six Flags for Physics Day. It’s April 24 in Georgia. If you’re outside of Georgia, know that Six Flags parks all over the country host similar outings in the spring.

Because we’ve been studying the Physics of Superheroes, our trip to Six Flags is extra special. Students will (in addition to all the great theme park physics we will do) get to ride the Batman and Superman roller coasters.

I’m starting my planning with the sweet physics day workbook, available for download from the Six Flags site.

Today, we watched The Science of Watchmen (6min), which introduced the students to several wave principles of energy. Then, I introduced them to light waves and early experiments to determine the velocity of light.

Wiipendulum Physics Lab

Grant, a student of mine, wrote a physics lab for his final project. He set up a pendulum with 2 choices of arm length and asked the rest of the class 1) for an object swinging on the end of the arm, when during the period is acceleration greatest? and 2) which would swing with a higher velocity — a Wiimote on the longer- or shorter-armed pendulum?

To gather data, Grant connected a Wiimote to his computer over Bluetooth. He then showed us how the Wiimote works:

Then he connected the Wiimote to his Apple laptop to display acceleration (in 3 axes, no less!) using DarwiinRemote.

Grant used a few web resources in devising his lab, here they are:

Oh, you wanna know the answers to Grant’s questions? 1) acceleration is maximized on the downward swing and 2) the Wiimote records a higher velocity when swinging on the long-arm pendulum.

Superhero Physics Class Highlighted

Watch my physics class highlighted on 11 Alive news.

Vector fun with Superman

Vector fun with Superman

I teach physics AND love superheroes. My mash-up? My Superheroes Physics class. The class is an absolute blast to teach!

This past week, I was fortunate enough to be spotlighted on the local news in their education segment. 11 Alive in Atlanta filmed and highlighted my physics class on Friday and the segment aired Monday morning.

My favorite part is that I was able to say “men in Spandex” on television. That and how many teachers do you know who can get away with wearing a Superman T to school — let alone on television?

Embedding doesn’t seem to be working properly, so you’ll have to click through to watch my physics class highlighted on 11 Alive news.

(I owe a huge debt of thanks to Dr. James Kakalios, author of The Physics of Superheroes, for the inspiration for the class as well as an excellent text from which to take examples.)