# Satisfying application of physics

## Main Question or Discussion Point

Today, I completed a lab test in my physics test, and received the highest grade in the class. The goal was to simulate a bungee jump. We had to make the payload, an egg in my case, get as close to the floor as possible without touching. To do this, you get a rubber band, and would then calculate a length of non-elastic string to attach to it. Our goal was within 3cm. The catch? you only get one try. I first got a large rubber band, and suspended it from a fixed arm about 2m off the floor. I measured the displacement of the rubber band, and use a force gauge to measure the force. I used those numbers in F=-kx to find the spring constant. I then found the elastic potential energy with Pe=1/2kx^2. I then took the weight of the egg, in newtons, and calculated the string length with P(elastic)=P(egg) and got .5m. My egg, dropped from the same point that the rubber band was attached to the support, was dropped, and promptly sprang back upon reaching 3cm almost exactly.

Just to sum up my work:
F=kx
9=13.84(.65m)

P(elastic)= 1/2kx^2
2.96= 1/2(13.84).65^2

2.96=mgh

2.96=.6(9.8)h

h=.5m

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ZapperZ
Staff Emeritus
2018 Award
Very, very good! That's the kind of physics "lab" that I like.

Zz.

Very, very good! That's the kind of physics "lab" that I like.

Zz.
thank you very much.

and BTW, I just met with my college course adviser for the first time today. I am "in", and I'm majoring in physics!!!!

dst
thank you very much.

and BTW, I just met with my college course adviser for the first time today. I am "in", and I'm majoring in physics!!!!
Great job!

I've had a few similar labs that just *worked* but most of these consist of overcomplicated setups that just manage to work, pure fluke.