PhysicsLAB: Cookie Sale Problem

A girl scout has to sell cookies in her neighborhood one Saturday morning. After walking out her door, she initially walks 15 meters, East, at 1 m/sec to arrive at her first customer's house. It takes her 180 seconds to ring the doorbell, have someone answer the door, explain her project, record their order and document their payment. She then walks 17 meters, North, at 1 m/sec to her second customer's house where, once more, she takes 180 seconds to complete the sale. Next she walks 25 meters, West, at 0.5 m/sec, to arrive at her third customer's house at which she completes her sale in 180 seconds. To reach her 4th customer's house, she walks 16 meters, South, at 0.5 m/sec and completes her sale in 180 seconds. Realizing that she is running out of time, she jogs 18 meters, East at 1.5 m/sec, to her 5th customer's house, completes her sale in 180 seconds, and runs 16 meters, South, at 2 m/sec to her 6th and final house where after taking 180 seconds she barely makes her deadline as she finishes with her morning activities.

In the following chart, supply the scout's travel times along with her x (E-W) and y (N-S) displacements for each step.

	travel	travel	travel	sales	travel
steps	distance	speed	direction	times	times	x	y
	(m)	(m/sec)		(sec)	(sec)	(m)	(m)

home

180

0.5

180

0.5

180

1.5

180

Summary Questions

What total distance did she travel from her home to house #6 while making her sales?

How much total time was required for her to travel from her home to house #6 while making her sales?

How much total time was required for her give her "sales pitches" and collect her orders?

What was her average speed during these morning's activities?

What was her net x displacement?

What was her net y displacement?

Map Construction and Conclusions

On a sheet of graph paper, draw a scaled vector diagram, or map, of the girl scout's morning route. Be careful to provide your scale and label each house's location. On your map, neatly show your calculations for each of the following questions.

I. What is the magnitude and direction of her net displacement from her home to house #6? This answer may be calculated or constructed and measured with a ruler and protractor.

II. What is the magnitude and direction of her average velocity from her home to house #6?

III. Why is your answer for the magnitude of her average velocity of her morning's activities not the same as your previous anwer for her average speed?

IV. State the exact direction that she would need to walk directly home once she finishes her sales at house #6. Explain how you determined this answer.