This week’s Please Explain is all about roller coasters—from the old classics like the Cyclone to the new wild rides like the Green Lantern! We're joined by two roller coaster experts: Jeffrey Rhoads, Associate Professor at Purdue University's School of Mechanical Engineering,  where he co-teaches a course in the physics of roller coasters, and Jacob Miller, PhD candidate at Purdue University's School of Mechanical Engineering (studying vibration), whose personal passion is the Millennium Force at Cedar Point in Ohio for its combination of "speed" and  "airtime."