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does more rain hit your car if


KILZ FILLZ

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its sitting still

or moving?

 

the same?

your car cant take up more Area one way or the other.

 

we couldnt come to an agreement at work.

i say its the same.

whatta you think?

 

 

 

 

heres some boobs...

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

( . )( . )

 

 

enjoy

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i'd guess it's the same if it is raining at the same rate everywhere

so, drive to the downpour or into the garage to make a difference.

 

i know though, riding a bike you get wetter the faster you go just because the rain is hitting you harder. but i don't think you get more rain on you.

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http://mathforum.org/library/drmath/view/61187.html

 

Rainfall on a Moving Object

 

Date: 09/10/2002 at 12:13:24

From: Susan Christy

Subject: Rainfall on a moving object

 

I would like to figure out the relation between a moving object (a

person) and the amount of rain that will hit him given a fixed

distance. If I'm running and you're walking 1 mile in a rainstorm, who

will get wetter?

 

Date: 09/10/2002 at 13:45:21

From: Doctor Rick

Subject: Re: Rainfall on a moving object

 

Hi, Susan.

 

Here are some things to consider.

 

The rain is coming down at some rate. How do we measure this rate? We

could measure the volume of water that comes down per second, but this

depends on the ground area over which you are measuring. If you double

the area, you'll find that twice as many cubic inches of water hit

that area per second. The correct measure, then, is something like

cubic inches per square inch of surface area per second. (These units

reduce to inches per minute; that's why the total rainfall during a

storm is measured in inches. It's really cubic inches per square

inch.)

 

Suppose we could know how big the raindrops are, and we could take a

snapshot and count the raindrops in 1000 cubic inches of the air at

one moment. Then, to find the rate of rainfall, we could multiply the

amount of water per cubic inch of air by the SPEED at which the

raindrops fall, in inches per second. If the amount of water is

measured in cubic inches, we'll have the rate in inches per second.

 

The rain is also coming down at a certain angle. You could simplify

the problem if you require that there be no wind, so the rain comes

straight down. But in doing the calculations for the moving object

(person), you'll find that it helps to think about rain coming down at

other angles. That's because we can apply "Newtonian relativity" -

which isn't as difficult to understand as Einstein's relativity. If an

object is moving at velocity v with no wind, it's the same as if the

object is stationary and there is a wind of velocity -v (that is, just

as fast in the opposite direction).

 

If rain isn't falling vertically, this doesn't affect the rate at

which it hits the ground, as long as we use the VERTICAL COMPONENT of

the rain in calculating the rate. The horizontal component only causes

the rain to fall at a different place; it doesn't affect WHEN a

raindrop hits the ground.

 

Now back to the measurement of the rainfall. I referred to a certain

area of ground -- the area of a horizontal flat surface. When you

consider the rain hitting the object (person), you'll need to consider

surfaces that aren't horizontal. Just as in the case of non-vertical

rainfall hitting a horizontal surface, what counts is the COMPONENT of

the rain's velocity PERPENDICULAR to the surface.

 

Putting it all together, here are the factors you'll need to consider

in calculating the amount of water that hits a moving object. First,

consider the object as a bunch of flat surfaces at different angles.

 

Find the angle at which the rain would be falling, if the object were

stationary and there was a wind as fast as the object is really

moving. (Note: This will require knowing the vertical speed of

raindrops; I'm sure this information is out there somewhere on the

Internet.)

 

Then for each of the object's surfaces, find the component of the

rain's velocity perpendicular to the surface, and use this to

calculate the rate at which water hits the surface.

 

Add up the rates for each surface, and you'll have the rate at which

the object gets wet. Finally, multiply by the TIME it takes for the

object to go the specified distance, and you'll have how wet it gets

in the course of the trip.

 

One final hint. You don't need a realistic division of the object into

surfaces; for a person, that would be really tough. All you really

need is one horizontal surface representing the area of the object's

shadow when the sun is directly overhead, and a vertical surface

representing the area of the object's shadow when a light is directly

in front of it.

 

See what you can do with this. I'd like to hear what you come up with.

Once you get the concepts involved, the math isn't all that

complicated. Don't worry about coming up with estimates for the three

numbers - rainfall velocity and the two shadow areas. You can get a

formula first and worry about the numbers later, if you find you need

them.

 

For discussions of who gets wetter in a rainstorm, a runner or a

walker, see:

 

To stay drier, do you walk or run in rain? If you walk,

researchers say, you're all wet - Eric Sorensen, Seattle Times

http://seattletimes.nwsource.com/html/localnews/134370003_rain23m.html

 

Do you get wetter if you run or walk in the rain?

http://www.physlink.com/Education/AskExperts/ae212.cfm

 

Which will keep you drier, running through the rain or walking?

http://www.straightdope.com/classics/a3_395.html

 

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its got to be more does the speed not square root the surface area? or at least i would think

 

on another note if 2 cars traveling at the same speed hit one another head on they cancel each other out, its equivalent to hitting a solid wall. that much i am certain.

 

not completely true.. gotta take into account the make/weight/other shit of the car.

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i drive a GX 470 for my work sometimes, and the windshield wipers speed up the faster you are going. i assume this is because you get more water splatter when you are going faster.

 

driving and running in the rain are different, when you run in the rain as oppose to walking you are flinging water off your feet onto your back.

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you forget one thing, it depends how long you stay there. Stay in the rain for 20 minutes, walking, running, or staying still wont make a difference, you'll be soaking wet. Time is an important factor here. The longer the time lapse, the more decreased the difference in the accumulated amount of rain in both situations becomes.

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i was told if you're driving in a convertable with the top down and you drive into rain, if you're goin' fast enough then you don't get wet. all the rain passes over you and hits the back seat.

 

they did that shit on mythbusters as well. it is possible when a certain speed is reached, but i think the conclusion was that you'd have to go faster than the speed a car can reach.

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