Phy 201
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.
** **
The problem:
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?
answer/question/discussion: You can calculate average velocity by taking the change in velocity over 2. This would give (10cm/sec-4cm/sec)/2 which gives 6cm/sec. My best guess for average velocity is 6cm/sec
• Without further information, why is this just a guess?
answer/question/discussion: This is only a guess because you don’t know if the velocity is increasing at a constant rate. It could be variable or increasing at an increasing rate.
• 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?
answer/question/discussion: You would take average velocity (10 cm/sec) and multiply it by the total number of seconds (3). This would give an expression of 10 cm/sec (3 sec) = 30 cm. Seconds would cancel out leaving cm at the units. Using average velocity causes the system to have a constant velocity that is easy to work with.
Good, but as you say above the ave rate is 6 cm/s.
• At what average rate did its velocity change with respect to clock time during this interval?
answer/question/discussion: To find the average rate that velocity changed, you must take the change in velocity which is 6cm/sec and divide it by the total time interval which was 3 seconds. This gives an average velocity change of 2 cm/sec/sec. Again this number is just a guess because you don’t know if the system is accelerating at a constant rate.
** **
10 minutes
** **
&#Good work. See my notes and let me know if you have questions. &#