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Discussion Starter #1
If a car, a friend's car, was traveling at such a speed that the car covers a mile in 42.39 seconds. How fast is the vehicle moving in terms of mph? So, seconds per mile to miles per hour I guess. Thanks in advance!
 

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was there an acceleration...if so that would change everything
 

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ok, disregarding acceleration:

60MPH is one mile a minute.
30miles an hour is one mile every two minutes, or half a mile a minute.

one mile in 45 seconds, at a constant speed, would be 90MPH.
So, at constant velocity, coverint a mile in 42.39 seconds is about 92/93 MPH.

Covering a mile from a dead stop in 42.39 seconds means you had to accelerate from zero, so you were likely going around 100-110 by the time you passed the mile line to compensate for speeding from a stop.
 

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phx, one mile in 45 seconds is not 90mph.

1 mile per 45 seconds = 80 mph:
60/45 = 1.333 miles per minute = 80 mph.

1 mile per 40 seconds = 90 mph:
60/40 = 1.5 miles per minute = 90 mph.
 

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Discussion Starter #10
The car, my friend's car, was on cruise control. So was it 92/93 mph or 84.xxxxxx? I googled it and used some sites but couldn't ever figure out how to get it just right. Which, believe it or not, is why I asked you guys
 

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Discussion Starter #12
Appreciate it Brian, thanks again everyone
 

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lol. Covering this in physics. lol. what your getting there is the average velocity. Assuming that it was a constant velocity, then that is correct. But to factor acceloration in, you would need more information I believe. It could be solved, but its pretty difficult.

I see cruise control up there, so thats a constant velocity. Formula is easy enough. Velocity = Distance/Time

V = 1 mile/0.011775 hours
V = 84.925690021231422505307855626327 m/h(mph) (as your average velocity considering that cruise control isnt perfect. With the information you gave thats as accurate as it gets as far as I know)
 

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dspurck2 wrote:

> Here's one. If you drive your car at the speed of light and
> turn the headlights on... do they work?
>

OK. first I'd like to say that I have no idea. but heres my hypothesis:

If you're traveling at the speed of light, and you turn on your headlights, they would burn out instantly. This is because a photon will only go the speed of light. If the filament itself is moving that the speed of light, all of the photons that would fire in the direction of travel would never actually leave the filament. Therefore the photons would build up in number pretty instantaneously and the heat generated would burn the filament out.
 

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"Here's one. If you drive your car at the speed of light and turn the headlights on... do they work?"

Your car has mass, anything with mass cannot travel the speed of light, But lets say you could travel 99.9% of the speed of light and if you decided to turn your headlights on you would see the light inching foward from your headlights. If it was possible to actually travel at those speeds I think the post above nailed it the filament would instantly burn out.
 
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