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You drive on Interstate 10 from San Antonio to Houston, half the distance at 55km/h and the other half at 90km/h. Waht is your average speed from San Antonio to Houson?
How do I do this?
How do I do this?
That's the problem with the lack of a good explanation of "average velocity" in physics textbooks.DrWarezz said:To find the average of something, you simply add up all the numbers you have, then divide by how many you have, as an answer to your question:
(55+90)/2 = 72.5
:)
[r.D]
Since v1t1=v2t2, I get 68.276 km/hr.DrWarezz said:Thanks robphy.
However, my solution answers the authors question, correct?
:)
[r.D]
You cannot apply the statistical definition of "average" to average speed. It is DEFINED, as stated, as the total distance travelled divided by the total time taken. Even though the total distance and time taken here are not given, this problem is still solvable if one stick to solving it symbolically in the beginning and not plug in numbers right away.DrWarezz said:Tide, that's the overall speed. Which would equal the average speed. So, you're not necessarily wrong, however, niether the time nor the distance are specified in the question. So, my answer is the one to go for :)
[r.D]
Well, you could certainly do that but consider this. Suppose you traveled at 50 km/h for the entire trip except that over the last meter you gunned it and traveled at the speed of light. Would your average speed have been half the speed of light?DrWarezz said:Tide, that's the overall speed. Which would equal the average speed. So, you're not necessarily wrong, however, niether the time nor the distance are specified in the question. So, my answer is the one to go for :)
[r.D]