Motion and Position-Time Graphs

[Jacobpm64]

A police officer clocked a driver going 20 mph over the speed limit just as the driver passed a slower car. He arrested both drivers. The judge agreed that both were guilty, saying, "If the two cars were next to each other, they must have been going the same speed." Are the judge and police officer correct? Explain with a sketch, a motion diagram, and a position-time graph.

Uhmm.. I'm not sure at all how to think about this.. If i look at it one way.. it looks like it would have to be the same.. because they'd meet at the same point where the distance / time would be the same on the graph.. but if i think about it.. it wouldn't be very smart to say that they'd have to be moving at the same speed.. or would it? I'm confused

 

[siddharth]

Think about this. One car, initially at the origin (say x=0) is going with a constant velocity of 100 m/s. Another car, initially 100m away(x=100) is going with a constant velocity of 50 m/s in the same direction. Will the cars pass? If so,what will the velocities of the cars be?