Your 'cq_1_05.1' 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 accelerates at 8 cm/s^2 for 3 seconds, starting with velocity 12 cm/s.
What will be its velocity after the 3 seconds has elapsed?
8 * 3 = 24
These numbers have units; units should be included with every quantity at every step of the solution.
24 + 12 = 36cm/sec^2
You did not include units with your quantities. However cm/s^2 are not units of velocity.
The velocity after the three seconds is 36 cm/sec
Answer/question/discussion:
Assuming that acceleration is constant, what will be its average velocity during this interval?
vAve = `ds/`dt
vAve = 24 cm/sec^2 / 3sec
`ds is displacement, and would not be measured in cm/s^2.
There is in any case no quantity in this problem that is equal to 24 cm/s^2.
vAve = `ds / `dt is correct, but while you know `dt, you don't know vAve and you don't know `ds. Until you know two of the three quantities you can't get any information from this equation.
You know the acceleration is uniform, and you know the initial and final velocities. How can you therefore find the average velocity?
vAve = 8 cm/sec
The object starts at 12 cm/s and speeds up. Its average velocity will be more than 8 cm/s.
There is in any case no quantity in the problem which is equal to 8 cm/s.
Answer/question/discussion:
How far will it travel during this interval?
It will travel 24 centimeters
You need to include the details of your reasoning, though in this case the result you give would follow from the initial velocity and time interval you are using. However that initial velocity is not correct.
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15 minutes
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When finding the average velocity during the time interval, I was not sure if I should or should not add the starting velocity of 12 cm/s.
12 cm/s is your starting, or initial, velocity. If you find the change in velocity, then you would add that to your intiial velocity to get your final velocity. You would then have initial and final velocity, which could be used to find average velocity.
You are misidentifying many of your quantities, and you don't appear to be using units throughout your calculations.