Random Problem 1

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course PHY 201

6/7 around 9:00I want to make sure I'm doing this correct

If the velocity of the object changes from 5 cm / sec to 15 cm / sec in 9 seconds, then at what average rate is the velocity changing?

15 cm/s-5 cm/s/9 sec=1.11 cm/sec^2

A ball rolling from rest down a constant incline requires 3.9 seconds to roll the 49 centimeter length of the incline.

What is its average velocity?

average velocity=49 cm/3.9 sec=12.56 cm/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?

12.56 cm/sec*2=25.12 cm/sec

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

12.56 cm/s-0 cm/s/3.9 s=3.22 cm/s^2

An automobile accelerates uniformly down a constant incline, starting from rest. It requires 13 seconds to cover a distance of 110 meters. At what average rate is the velocity of the automobile therefore changing?

average velocity=110 m/13 s=8.46 m/s

8.46 m/s*2=16.92 m/s final velocity

16.92 m/s-0 m/s/13 s=1.30 m/sec^2

I want to make sure I am do all of this right????"

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Very good.

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