RandomProbAssign2-1

course 231

2/11; 5:25pm

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?(16-4)/8 = 12/8 = 1.5cm/s^2

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?

97cm/8.2s= 11.8cm/s

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?

11.8cm/s * 2 = 23.6cm/s

• What average rate is the velocity of the ball therefore changing?

23.6cm/s/8.2s = 2.88cm/s^2

Good.

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?

132m/10s = 13.2m/s.

That's the average rate of change of position with respect to clock time, not the average rate of change of velocity with respect to clock time.

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