George is driving 100 ft/sec toward an intersection.
He looks to his right, and sees Bill, driving 30 ft/sec toward the same intersection. George foolishly slams on his brakes.

If he had kept going 100 ft/sec, he would have been through the intersection long before Bill got there.

At the instant that he slams on his brakes, the center of George's car is 125 ft from the intersection, and the center of Bill's car is 150 ft from the intersection. George's brakes give his car an acceleration of -30 ft/sec².
Bill never changes his speed.
Each car is 13 ft long and 7 ft wide.

Will there be a collision?

(In reply to Hey guys!! by FatBoy)

FatBoy,

First, I think you are comparing the time when George comes back to intersection (in reverse, rather than the first time he goes through).

And second, Charlie is taking into account the notion that the center of the car is not travelling down the center of the road... which I think is a little extreme and not what DJ intended.

Either way, this will explain the difference.

But in the spirit of this site, I think you should actually read the previous posts and endeavor to understand what he (Charlie) said, and if necessary summon the will to learn/grow. That can be fun too.

--- SK

Posted by SilverKnight on 2003-10-02 13:56:27