Your 'cq_1_02.1' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
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A ball starts with velocity 4 cm/sec and ends with a velocity of 10 cm/sec.
• What is your best guess about the ball's average velocity?
4cm/sec + 10cm/sec = 14cm/sec; 14/2=7cm/sec
I would say the ball has an average velocity of 7 cm/sec
• Without further information, why is this just a guess?
The ball could have actually immediately sped up to 10cm/sec and traveled the whole time at that speed, therefore the average velocity would be higher. Without knowing what the actual outcome was, we have to guess.
• If it takes 3 seconds to get from the first velocity to the second, then what is your best guess about how far it traveled during that time?
With an average velocity of 7cm/sec after 3secs, it would have traveled 21cm.
• At what average rate did its velocity change during this time?
10cm/sec – 4cm/sec = 6cm/sec / 3 sec = 2cm/sec
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10 mins
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I'm not sure that I calculated the last question correctly.
Except for the units your calculation was correct; be sure you see how it is an application of the definition of average rate of change.
The units: (cm/s) / s = (cm/s) * (1/s) = cm/s^2.
&#Good responses. See my notes and let me know if you have questions. &#