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course PHY 121
2.21.11 at 2:42pm
Random Assignment 2 Problem 1#$&*
course PHY 121
2.18.11 at 6:00pm
If the velocity of the object changes from 4 cm / sec to 16 cm / sec in 8 seconds, then at what average rate is the velocity changing?The change in velocity is -2cm/sec. The average rate of change in velocity is that divided by the change it time, or (-2cm/sec)/(7sec).
A ball rolling from rest down a constant incline requires 8.2 seconds to roll the 97 centimeter length of the incline.
What is its average velocity?
vAve = 'ds/'dt
=97cm/8.2sec
=11.83cm/sec
An object which accelerates uniformly from rest will attain a final velocity which is double its average velocity.
What therefore is the final velocity of this ball?
23.66cm/sec
At what average rate is the velocity of the ball therefore changing? 17.75cm/sec
An automobile accelerates uniformly down a constant incline, starting from rest. It requires 10 seconds to cover a distance of 132 meters. At what average rate is the velocity of the automobile therefore changing?
vAve=132m/10sec
=13.2m/sec
final velocity = 26.4m/sec
@& Correct so far.*@
avg rate velocity changing = 19.8cm/sec
&&&&This was calculated my averaging average velocity of 13.2m/sec and final velocity of 26.4m/sec.&&&&
@& Thanks for clarifying; I can see what you did.
However that doesn't give you the average rate at which the velocity changes.
Please answer the following:
By how much does the velocity change during this 8.2 second interval?
What is the definition of the average rate of change of velocity with respect to clock time?
What therefore should the result here be?*@
@& But again I can't tell how you got your final result.*@
@&
&#Please see my notes and, unless my notes indicate that revision is optional, submit a copy of this document with revisions and/or questions, and mark your insertions with &&&& (please mark each insertion at the beginning and at the end).
Be sure to include the entire document, including my notes.
If my notes indicate that revision is optional, use your own judgement as to whether a revision will benefit you.
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*@"
Self-critique (if necessary):
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@& Thanks for the clarification.
Please see my note and submit a revision with answers to my questions, and mark your insertions this time with ####.
I believe this will go a long way toward clarifying the challenging concept of the rate of change of velocity.*@