Fast Wheels

[landie]

Starting with the assumption that the topmost part of a moving vehicle's wheels travel at twice the speed of the vehicle. How is the accuracy of a speed detector affected when the beam is concentrated at the side of the vehicle.

The above assumption is based on the fact that the bottom of the wheel matches the speed of the road (i.e. zero), the hub travels at the same speed as the vehicle and the topmost part of the tyre travels at speed x 2. It needs to do this to get back to the road in time. Sorry if that's a bit long-winded.

[verrecchia]

The radar in a speed camera picks up the whole car and times it over a set distance, it doesn't matter what speed different parts of the car are travelling at, as for handheld radars, the principle is the same, distance over time, the officer would point it at the front of your car, not at the side, the beam is not a thin laser beam but more of a wide infra red type beam so it would not concentrate on a mm sized piece of your car, plus you would have to be along side him for him to point it at the side of your car. so just admit you were speeding and pay the fine, only kidding

[landie]

Thanks Verrecchia,

Touch wood, I haven't been been speeding. It's just a theoretical question.