(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

From t = 0 to t = 5.00 min, a man stands still, and from t = 5.00 min to t = 10.0 min, he walks briskly in a straight line at a constant speed of 2.5 m/s.

What is his average acceleration aavg in the interval 2.00 min to 8.00 min?

2. Relevant equations

I know that in the formula the A_avg is ∆V/∆t... but I can't make it work for me. It says the answer is .00694 m/s^2, but I keep getting a different answer.

3. The attempt at a solution

I tried to calculate the final velocity (V_f): ∆d/∆t: [2.5 m/s x 180 s]/480s. (or 2.5 m/s x 3 minutes)/8 minutes). This give me 0.975 m/s^2.

The initial velocity (V_i) seems to me that it would be 0 at t=2 minutes.

So A = [.975-0]/∆t = [.975 m/s]/360s = .0027 m/s^2.

but this is wrong.

Help please. where did I mess up?

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# Homework Help: Average Acceleration Confusion

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