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puneeth
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Homework Statement
Suppose it is raining at a constant rate (at any instant the number of raindrops in a given volume of space will be constant) . there is no wind and rain falls vertically. two persons of same size (height, stoutness etc) set out to travel a fixed distance say d meters in a straight path one on a bicycle moving at const. speed of 10 Km/hr and other on a bike moving with 20 Km/hr. who gets more wet?
N.B : they travel WITHOUT stopping.
Homework Equations
distance/time = speed.
volume swept during journey = surface area x speed
The Attempt at a Solution
when a person moves in space the raindrops hitting him are those which should have been present in the space which he occupies at that particular instant. suppose that the person is photographed at a particular instant, the raindrops which hit him at that instant are those which were present in tthe volume he occupies in that instant. since he is in a state of continuous motion the drops on, beside before, or behind him do not affect him.
also since rain falls at a constant rate the number of raindrops striking a person during his journey should then equal the volume swept by him x no. of rain drops per unit volume.
since both are of the same size and move same distances the volumes swept are equal.
then it leads to the conclusion thar both are wetted to the same extent.
this conclusion seems to oppose common sense, for we run to our destinations rather than walking when it rains - but in both cases we are wetted to the same extent!
hence I doubt the validity of the arguement.
please think about this problem and state your views about it. if my views are incorrect I'd be thankful to know the correct answer and the argument which will leads to it.