Measuring the average speed of an object

AI Thread Summary
The discussion revolves around measuring the average speed of an object using the formula s=d/t, but participants express uncertainty about its application in a specific context. One contributor suggests calculating the total time and using the area under a graph to find distance, while also noting that instantaneous speed requires drawing a tangent. There is a consensus that simply applying the average speed formula may not suffice for a three-mark question, especially given the follow-up questions. Additionally, there is a clarification on the misconception that average speeds can be simply averaged from different speeds. The conversation emphasizes the need for a deeper understanding of how to measure average speed effectively.
Griffy11
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Hi everyone,

http://img372.imageshack.us/img372/6093/img009h.jpg

With the above, I really have no idea other than the standard s=d/t formula, but I doubt that has anything to do with it for a question worth 3 marks, and then looking at the two questions below, it'd make no sense.

The other idea I had was finding the total time, then the area under the graph for d, giving you s=d/t again, but using the method I just described. Then 25c would be answered by saying that finding instantaneous speed required a tangent drawn to the point etc, as opposed to the whole area under the curve.

Is the idea of finding d and t using area under the graph right, or am I way off?

Thanks for the help in advance.
 
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Bump. :)
 
dude look a) Vm=X-X0/T-T0=deltaX/deltaT so this is for the avarage speed .
 
I've never heard of this formula before, so it's something which we haven't covered in class yet. Hence - it can't be right.
 
ah i now , now it is about the uinits i wrote them in my lengauge but this formula is for the avarage speed but i don't now how to writte them in english sorry but it is the formula for avarage speed
 
and another thing the avarage speed u can discribe it like this if a car moves with a speed of 3 km/h at the start and 5 km/h at the end u can't put together 5 + 3 and get 8km/h then divide it by 2. 8:2=4km/h so the avarage speed now is 4 km/h so even if the car dosent achive to have this speed but it is simpel to tell that the car can end the road at this speed sorry for my english i now it is bad but it is my 4 lengauge and i am learning it now since 4 months but i see i get better
 
I'm aware that there is a formula for average speed (s=d/t), but something like that wouldn't cut it for a 3 mark question, especially when there's two follow-on questions after it. The question also asks how you would measure the average speed, rather than what average speed is.

Also, don't worry about your English, it's not that bad! ;)
 

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