怎么讓汽車貼在墻上行駛

　　Probably every race car driver today played with Hot Wheels cars as a kid, and imagined what it would be like to go so fast that you could drive around the wall of a race track without rolling over.

　　Turns out that’s not as impossible as it sounds.

　　Some physics students at the University of Leicester in the U.K. worked out the math.

　　Four factors are crucial in keeping a car up on a vertical curve: friction between the tires and the track; the weight of the vehicle; its speed; and how hard the car presses into the road, which depends on its aerodynamics. The work appears in the Journal of Physics Special Topics. [B. Jordan, O. Youle, T. Morris and K. Raymer, Racing on the Edge]

　　An Indy race car hugs the road at high speeds. And on a circular track as long as the one in Indianapolis, it would have more than enough sticking power to cling to a vertical wall at 150 miles an hour.

　　But do not try this yourself. Most consumer sports cars don’t press down when they go really fast—they lift up…up and away.

　　—Wayt Gibbs