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        riddles >> medium >> hard rain
        
(Message started by: lukes new shoes on Nov 18^th, 2002, 12:29am)

Title: hard rain
Post by lukes new shoes on Nov 18^th, 2002, 12:29am

a man is two kilometres from his house when it starts raining. he can walk at a speed of 1km per minute or run at 2km per minute. what should he do to remain as dry as possible?

Title: Re: NEW PUZZLE: hard rain
Post by towr on Nov 18^th, 2002, 12:56am

Hide under a tree, open his umbrella, etc

If the only option for action is walking or running he should run.

though I very much doubt anyone can walk at 1 km per minute, since that 60 km per hour, which even most cyclist can't match. 2 km per minute is 120 km/h which is the maximum speed allowed for cars around here..

Title: Re: NEW PUZZLE: hard rain
Post by lukes new shoes on Nov 18^th, 2002, 1:10am

ok, the man is caught out in the open (no trees to hide under) and has no devices to keep him dry.
change his walking speed and running speed to 1km/5mins and 2km/5mins respectively if u like.

Title: Re: NEW PUZZLE: hard rain
Post by towr on Nov 18^th, 2002, 7:57am

well, the exact speed doesn't really matter much (up to a point).

Walkingspeed gets you wetter than runningspeed over the same distance.. Something they actually tested in an experiment..
That's assuming the rain is at a constant level. If it rains progressively harder its more obvious that running will keep you dryer. When the rain is getting progressively lighter walking might keep you dryer in some cases.

Title: Re: NEW PUZZLE: hard rain
Post by James Fingas on Nov 18^th, 2002, 8:53am

It depends on the direction the rain is falling. If it's falling straight down, he will get equally wet (to a point--his head will get wetter walking). The front of his body will get about the same wetness whether he walks or runs.

However, if the rain is coming down in his face (ie. wind in his face), then he'll get wetter walking. If the rain is coming down slightly on his back (ie. small wind at his back), then he may get wetter running, and if the rain is coming down hard on his back (ie. strong wind at his back), he'll get wetter walking.

Title: Re: NEW PUZZLE: hard rain
Post by Icarus on Nov 18^th, 2002, 3:30pm

It also depends on whether or not the rain is steady. If it's a downpour for the amount of time it would take him to run home, then slacks off to a light sprinkle, he would be better off walking (of course he wouldn't know this). In a steady rain falling straight down, his "front" will encounter the same amount of water regardless of how fast he goes. The amount of water landing on his "top" increases with time however, so he is better off running.

Title: Re: NEW PUZZLE: hard rain
Post by Garzahd on Nov 18^th, 2002, 4:24pm

Technically, I suppose it matters how tall the guy is compared to the size of his head. If the guy in question happens to be Charlie Brown or Calvin, he should run as fast as he can.