SOLUTION: Please help. I have been trying to make sense if this for days now. Question : A 50ft long bungee will stretch a certain amount, depending on how much the person doing the jump

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Question 26755: Please help. I have been trying to make sense if this for days now.
Question : A 50ft long bungee will stretch a certain amount, depending on how much the person doing the jump weight. The following table tells how much a bungee cord will stretch for certain weights. The stretch is in addition to the original 50ft length of the bungee cord.
Weight(lbs) ............................Stretch (ft)
100..........................................80.9
110..........................................86.7
120......................................... 92.4
130..........................................98.1
140..........................................103.7
a) Draw a graph with weight as the independent variable and the stretch as the dependent variable.
b) Write an equation that will predict the stretch distance , d, for a given weight, w
c) If the concrete is 200 ft below the point where the bungee cord is attached , what is the heaviest "safe"weight for a 6ft tall jumper. Assume bungee cord is attached to jumper's ankles.
Answer by bmauger(101) About Me  (Show Source):
You can put this solution on YOUR website!
For part a) the independent variable is placed on the x axis, and the dependent variable is on the y-axis. The neater you do it the more accurate your results will turn out, so if you have graph paper, now's the time to use it.
b) When you get done, your dots should approximate a line. Draw this line on the graph. Use this line to find two things, the y-intercept of the line, and the slope of the line. The y-intercept is the y value where your line crosses the y axis. Slope is going to be the rise over the run, or the vertical change divided by the horizontal change of any two points on the line. Recall the equation for the line is:
y=mx%2Bb where m is the slope and b is the y-intercept. So IF you find your slope to be .55 and your intercept to be 25, then your equation would be:
y=%28.55%29x%2B25 or in your case:
d=%28.55%29w%2B25
THIS IS AN EXAMPLE ONLY, YOU'LL HAVE TO FIND OUT THE EXACT NUMBERS
c) Use your equation from part two to solve for weight. Don't forget to subtract the length of the rope (50') and the height of the person (6') from the height of the bridge and maybe a factor for safety (20'? ask your teacher?). So using our EXAMPLE equation:
d=%28.55%29w%2B25 using d=200-50-6-20=124 gives:
124=%28.55%29w%2B25 rearranging for w:
99=.55w dividing both sides by the slope (.55):
188=w so your answer (IN THIS EXAMPLE) is 188 lbs.