How Do You Calculate Average Speed with Variable Acceleration?

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To calculate average speed with variable acceleration, the formula used is total distance divided by total time. The discussion highlights the importance of determining both the total distance and total time when dealing with segments of constant acceleration followed by constant speed. A hint suggests substituting numerical values for time variables to clarify the total time calculation. The conversation emphasizes the need to sum distances and times accurately to find the correct average speed. This approach ensures a clearer understanding of how to handle variable acceleration scenarios.
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Homework Statement


In the file below.

Homework Equations


Speed= total distance over total time.
Acceleration = change of speed over time

The Attempt at a Solution


[/B]
I tought it is just E because of the first rule above. But then I doubt my answer since it moved with constant acceleration first then constant speed. However, I don’t see thant any of the choices fit. Can someone help?
 

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Your definition for speed is actually the definition for average speed. What is the total distance and what is the total time?
 
Sum of distance and sum of time?
 
What is the sum of the distances? How much time elapsed in covering those distances?
Hint: for total time, try replacing t1 and t2 with numerical values to get an idea of total time in letter variables.
 
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Is it not d1+d2 for total distance? Aha, the hint makes this clear; it is just t2.
Next time I will assume some values. Thanks a lot.
 
Well, I made the same mistake at first.
 
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Thread 'Correct statement about size of wire to produce larger extension'

Thread 'Correct statement about size of wire to produce larger extension'

The answer is (B) but I don't really understand why. Based on formula of Young Modulus: $$x=\frac{FL}{AE}$$ The second wire made of the same material so it means they have same Young Modulus. Larger extension means larger value of ##x## so to get larger value of ##x## we can increase ##F## and ##L## and decrease ##A## I am not sure whether there is change in ##F## for first and second wire so I will just assume ##F## does not change. It leaves (B) and (C) as possible options so why is (C)...
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