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LAB: Barbie Bungee Jumping Name: _________________________________________ Date:_________

Block:________

Introduction Your team has been hired to work for the Evil Knievel Entertainment Company. This

company provides rock climbing, sky diving, extreme skateboarding, and hang gliding adventures to the

public. The current market research indicates that the company should add bungee jumping to its list of

entertainment services. As part of the preliminary research, the management assigned teams the task of

working out the details of the jump that will ensure a safe yet thrilling experience.

Purpose To design a safe and yet thrilling jump using the relationship determined between jump

height and the number of rubber bands used to make the bungee cord.

Materials - One Barbie doll or other action figure

Meter stick

Rubber bands (two small and several large)

Balance

Day 1: Data Collection

1. Use one small rubber band to secure Barbies ankles together and to serve as a point ofattachment for the bungee cord. This rubber band does not count in the total length of the bungee.

2. Use a second small rubber band to tie back Barbies hair if it is not already in a ponytail. 3. Mass Barbie on the balance (in grams), and convert to kilograms. Record the mass in Table 1.4. Construct a bungee cord composed of two large rubber bands (your teacher will show you how to

do this) and attach it to the small rubber band around Barbies ankles.

5. Let Barbie hang upside down, and measure the distance from the free end of the bungee (the endNOT around her ankles) to the tip of her head. Measure in centimeters and then convert to meters.This is the initial length of the two-band bungee cord. Record the data in Table 1.

6. Place Barbie in a standing position on the edge of a desk or table. Allow her to bungee jump, andtake a reading of the total stretched length of the bungee (again, from the free end to the tip of

her head). Repeat for a total of three readings; record your data in Table 1 under Drop Distance.

All data must be recorded in meters!

7. Add a rubber band to your attached bungee cord. Measure the new un-stretched length. DropBarbie three times and record the data.

8. Repeat step 7 until your bungee cord has a total of six rubber bands. You may have to devise away to take measurements that are longer than 1.0 meter!

9. Calculate the average of the data and record it in the data table.

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Table 1. Bungee Data

Mass of Barbie (kg) =

Number of

Rubber

Bands

Initial

(Unstretched)

Length of Bungee

(m)

Drop Distance (Stretched Length) (m)Precise?

(yes/no)Trial 1 Trial 2 Trial 3 Average

Once you have collected your data, clean your lab station and return to your seat.

DO NOT go on with this lab until you have reviewed and taken notes over graphing in class or on the

website.

Day 2: Analysis

1. Using the data from Part I, construct a graph of Average Drop Distance (meters) vs. Number ofRubber Bands. Average Drop Distance is the dependentvariable, in that its value depends on the

number of rubber bands (independent variable) that you use. Properly scale your axes and be sure

to provide a graph title, axes titles, and units used on the axes.

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2. Draw a line of best fitthrough your data points by approximating a line that has an equal numberof data points above it as below it (in other words, a good average of all of your data). Lines of best

fit are used to approximate a linear regression trend in your data we will use these throughout

the year! Do not connect your data points dot-to-dot style!

3. From your graph, find the y-intercept.

4. Calculate the slope of your line by using the slope formula: m = (y2 y1) / (x2 x1). You mustcircle the two points you choose on your line.

5. Using the y-intercept and the slope you calculated in Steps 3 and 4, write your regression equationin the formy = mx + b.

6. Use the Best Fit Line equation to predict how many rubber bands will be needed in order forBarbie to perform a safe, yet thrilling jump for the distance your teacher specifies. Request this

number of rubber bands from your teacher and assemble your bungee cord.

Conclusion Questions:

1. Use your equation to predict how many of your rubber bands would be needed to allow Barbie asuccessful, yet thrilling jump from a height of 100 meters.

2. Use your equation to determine how far Barbie will fall if she uses 70 rubber bands.

3. What are the units of the slope on this graph? What is the meaning of this?

4. Explain why the y-intercept is not zero.

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5. Ken wants to jump and have some fun, too. Barbie loans Ken her bungee cord, but warns Ken thatthis may not be a safe plan. Why may it be a bad idea for Ken to use Barbies bungee cord?

6. Were you accurate in your prediction? Justify your answer.

7. Write a few sentences about sources of error in your experiment. (Note: human error andcalculation error/ are not sources of error. If you were making a mistake, you should just fix it!)

Discuss sources of error that are part of the experimental design and how they would affect your

data (values are too large? too small?).

BONUS:

8. Calculate the stretch coefficient for the trial that used 4 rubber bands by using the followingformula:

)(

)(

kgBarbieofMass

mStretchofAmountFactorStretch

9. A student measured the mass of Barbie before attaching the first rubber band that secures herankles to the bungee cord. How will this error affect the outcome of her jump? Your answer

should state clearly whether bungee would stretch more, less, or the same as expected, and must

be justified.