杏吧原创

In the TV programme Knight Rider, lead actor David Hasselhoff drives his talking car, Kit, up and onto a moving lorry via a ramp projecting from the back onto the road, often at high speed. The same thing happened in the original The Italian Job movie starring Michael Caine. But is this possible? As soon as the car hits the ramp, it would be moving relative to the lorry and therefore would only have the length of the inside of the lorry in which to brake, probably ending up crashing into the cab. Am I correct?

Continued)

A couple of corrections from the purists. The car in Knight Rider is not Kit, but KITT, Knight Industries Two Thousand. Second, in The Italian Job, the Minis drive into the back of a converted bus, not a truck 鈥� Ed

All your correspondents providing answers to the problems of The Italian Job stunt are concerned with the relative speeds of the wheels and the ramp and the potential for the adverse impact of almost instantaneous changes in speed.

鈥淏y using a roller ramp there is essentially no impact and instead a smooth slow-down鈥�

However, there need be no problem. By using a roller ramp, like those used in industrial conveyer systems, there would be essentially no impact because the rollers have a relatively small inertia and speed up very quickly. The problem of stopping the vehicle once on the ramp could then be addressed by using friction in the rollers to make them progressively harder to turn the further up the ramp they are. The result would be a smooth slow-down and none of the problems that troubled the three Mini drivers in the movie.

David Sharman, Richardson, Texas, US