What Is the Average Acceleration of a Downhill Skier?

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The average acceleration of a downhill skier can be calculated using the formula a_avg = (v_final - v_initial) / (t_final - t_initial). In this case, the skier starts at an initial speed of 2.5 m/s and accelerates to 20 m/s over 3.8 seconds. The change in velocity is 20 m/s - 2.5 m/s, resulting in a total change of 17.5 m/s. Dividing this change by the time interval of 3.8 seconds yields an average acceleration of approximately 4.61 m/s². Understanding the correct application of the formula is crucial for accurate calculations.
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This might be an extremely easy question and I'm just over-thinking it, but could someone give me a hand with some grade 10 physics?

1. A downhill skier has an initial speed of 2.5 m/s. She accelerates up to a speed of 20 m/s in 3.8 s.

a) Calculate the average acceleration of the skier.


Okay, so I know that acceleration equals velocity over time, but I'm slightly confused. So I know how to calculate the acceleration of 20 m/s in 3.8 s. Which is ... (about) 5.26. But, I get stuck here.
 
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Why are you confused? Explain.
 
I don't know how to find the average acceleration.
 
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wait, is that all I have to do?
 
No, your answer isn't correct. Average acceleration is the change in velocity over a given time interval. So what's the velocity at the beginning of your time interval, and what is it at the end?

Do you recognize this: a_{ave} = \Delta v / \Delta t
 
a_{ave} = \frac{\Delta v}{\Delta t} = \frac {v_{final} - v_{initial} }{t_{final} - t_{initial} }

it is definition :wink:
 
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