#$&* course Phy 201 2/13/11 around 3pm If the velocity of the object changes from 3 cm / sec to 13 cm / sec in 7 seconds, then at what average rate is the velocity changing? A ball rolling from rest down a constant incline requires 4.6 seconds to roll the 54 centimeter length of the incline. * What is its average velocity? 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? * At what average rate is the velocity of the ball therefore changing? An automobile accelerates uniformly down a constant incline, starting from rest. It requires 14 seconds to cover a distance of 106 meters. At what average rate is the velocity of the automobile therefore changing? Average velocity= (change in position)/(change in time) (13cm-3cm) = 10cm change in position change in time is 7seconds 10cm/7seconds= 1.43cm/sec/sec average rate of velocity change 54cm/4.6seconds=11.7cm/sec average velocity Final velocity = 2x11.7cm/sec = 23.4cm/sec average velocity of the ball is changing at a rate of 2 since the velocity doubled from rest to final.
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