(III) Mary and Sally are in a foot race (Fig. 2–39). When

QUESTION:

(III) Mary and Sally are in a foot race (Fig. 2–39). When Mary is 22 m from the finish line, she has a speed of \(4.0\mathrm{\ m}/\mathrm{s}\) and is \(5.0\mathrm{\ m}/\mathrm{s}\) behind Sally, who has a speed of \(5.0\mathrm{\ m}/\mathrm{s}\). Sally thinks she has an easy win and so, during the remaining portion of the race, decelerates at a constant rate \(0.40\mathrm{\ m}/\mathrm{s}^2\) of to the finish line. What constant acceleration does Mary now need during the remaining portion of the race, if she wishes to cross the finish line side-by-side with Sally?

Equation Transcription:

Text Transcription:

4.0 m/s

5.0 m/s

0.40 m/s2

4.0 m/s

5.0 m/s