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On the German autobahn, the recommended speed is 130 kilometers per hour. ...

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brandih | eNotes Employee

Posted October 28, 2013 at 4:35 PM via web

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On the German autobahn, the recommended speed is 130 kilometers per hour.  Approximately what is this speed in feet per second?

A. 0.023 foot/second

B. 119.167 feet/second

C. 305.067 feet/second

D. 7150 feet/second

Tagged with math, speed

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tiburtius | High School Teacher | (Level 3) Associate Educator

Posted October 28, 2013 at 4:55 PM (Answer #1)

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`1"ft"=0.3048"m"` (this is the definition of a foot) and since `1"m"=0.001"km"` we have

`1"ft"=0.0003048"km"=>1"km"=1/0.0003048"ft"`

Also `1"h"=3600"s"`

Now we have everything we need to calculate how many ft/s is 130 km/h.

`130"km/h"=130cdot (1/0.0003048"ft")/(3600"s")approx118.47477"ft/s"`

In the above line we've put `1/0.0003048"ft"` instead of 1km and 3600s instead of 1h.

130km/h is approximately equal to 118.47477ft/s.

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