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The Physics of Winter Biking |
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Wheel Size Suspension Brakes Helmet Color Bibliography |
A helmet is smething that is not especially important to winter biking more than it is to summer use, but the physics of it are interesting. Accorning to Newton's second law, the force acting on an object from a collision with another object is equal to its net change in momentum (that is, velocity times mass) over the change in time. If you're biking, and you fall and hit your head on the ground, and come to a complete stop, your mass should not change (depending perhaps on the severity of the colission), and your velocity will move from your original velocity to zero. Therefore, an excellent way to reduce the force of this collision is to increase the time over which it occurs, and this is exactly what a helmet does. As the styrofoam helmet gives way, it takes time, and reduces the force acting on your head. This is the same function served by a bumber of a car, or when you bend your knees after a fall. |