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Physics 211, Quiz 3

Question 1:

See Dick run! See Jane run! Run, Dick! Run, Jane!

Jane runs at 4.27 meters per second. Dick runs at 4.38 meters per second.

See Dick and Jane start a 10 km race together. Run, run!

How far ahead of Jane is Dick when he finishes?

  Answer:   The time it takes each to finish the race is

                              10,000 m
                Dick:   t  =  --------  =  2283 seconds
                              4.38 m/s

                              10,000 m
                Jane:   t  =  --------  =  2342 seconds
                              4.27 m/s

            Therefore, Dick finishes 2342 - 2283 = 59 seconds earlier.

            At the time that Dick finishes, Jane has been running for
            2283 seconds.  She has run

                Jane:   d  =  (4.27 m/s) * (2283 s) =  9748 m

            And therefore she is

                       10,000 m - 9748 m =  252 m   behind Dick

Creative Commons License Copyright © Michael Richmond. This work is licensed under a Creative Commons License.