# drag

Title Post date
How big was the aerodynamic force on Felix Baumgartner at 1342 km/h? (Or on Alan Eustace at 1321 km/h?) Keywords: aerodynamics, drag, felix baumgartner, free fall

Did you watch Felix Baumgartner jump out of a balloon gondola at an altitude of 39 km? Here's a question for your physics students, or even your physics teacher! How big was the drag force on Felix Baumgartner at his maximum speed of 1342 km/h? Pretty enormous, right? Wrong.

Knowing next to nothing about how aerodynamic drag varies as one hits the sound barrier, there is very simple way to assess the aerodynamic drag on a falling object at its maximum speed. Even at 1432 km/h. In fact the maximum aerodynamic drag occurs afterwards when the falling object is slowing down in the denser lower atmosphere. To asses how big the force was on Felix Baumgartner, we create a simple mathematical model of his fall.

6 years 31 weeks ago
Energy Use in Cars 2: Constant Speed Cruising Keywords: air resistance, drag, efficiency, energy use in cars, fuel economy, vehicle transportation

If a body in motion tends to stay in motion, why do we need to burn gas to travel at highway speeds?

Why do we need to burn gas to keep travelling at the same speed? The basic answer is "because if we didn't, eventually the car would stop." In everyday life, there is always friction and air resistance that opposes any motion, and if you leave a moving object alone, this friction and drag will eventually cause it to stop. This lecture looks at how this drag impacts a car.