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course phy 121

2/8 2:21

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 (start in the next line):

10cm/sec + 4cm/sec /2

=14 cm/ sec /2

=7cm/sec

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Without further information, why is this just a guess?

answer/question/discussion (start in the next line):

We do not know how long it took or how far it took to reach those velocities.

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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 (start in the next line):'

Average Velocity=change in distance/ change in time

7=ds/3 multiply each side by 3

ds=21 cm

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At what average rate did its velocity change with respect to clock time during this interval?

answer/question/discussion (start in the next line):

10 cm/s -4 cm/s / 3 seconds

=6cm/s/ 3 seconds

=2 cm/sec ^2