Anyone who saw Mark Webber’s crash at the European Grand Prix will be amazed that he walked away. But it turns out physics can tell us why, as the good people at The Red Bulletin can reveal...
Up In The Air
“I knew I was involved in a huge crash, and that I was just a passenger,” says Red Bull Racing driver Mark Webber. “The landing wasn’t too hard. It was OK because I had massive forward momentum. I knew there was a lot of run-off down there and I was happy it was a tyre wall that I eventually hit.”
Down To Earth
“It may sound like a cliché, but there is no way to escape the laws of physics,” says physicist Professor Thomas Schrefl. “The kinetic energy of the car, mv²/2, is three million joules, whereby m is the mass of the car and v is its velocity. Looking at Webber’s recent backflip, we immediately think that kinetic energy is transferred into potential energy, mgh, and rotational energy, Iw²/2. Webber takes off from the ground by h = 2m and rotates at an angular velocity, , of about 180 degrees per second (1, 2, 3). Here m is the total mass, g is the acceleration due to gravity, and I is the moment of inertia.
“However, doing the maths we see that the potential energy and the rotational energy take up about one to two per cent of the kinetic energy. After hitting the ground, Webber’s car slides towards the tyre barrier. Sliding means friction. The frictional force is FR = µmg, whereby µ is the friction coefficient between the car and the ground. The work, FRs, done by the frictional force is calculated simply: force times distance to the barrier. Friction reduces the kinetic energy by roughly 10%”
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