How stretching a rubber band, affects the range of a shot?

In summary: Yes, you can see the error bars when you zoom in. In summary, Homework Statement The attempt at a solution for a problem with a linear relationship between the stretch and the range produced an inaccurate line of regression. Additionally, the plot of the data is unconventional and may be confusing to viewers.
  • #1
rasalzari
27
2

Homework Statement


I did an experiment on how stretching a rubber band, affects the range or distance of a projectile shot.
Variable list:
  • Independent Variable
    • Amount of stretching
  • Dependent Variable
    • Range or distance
I created my catapults on my own and used two different rubbers bands and compared them
upload_2017-4-8_15-33-28.png

upload_2017-4-8_15-33-54.png


2. The attempt at a solution
Then I calculated the average, however i wanted to show that there is a linear relationship between the stretch and the range, but i don't know much about it. so can you help in determining whether what i did was right or wrong?
upload_2017-4-8_15-37-35.png
upload_2017-4-8_15-37-1.png


Then I graphed the average and produced a line of regression, but it didnt pass through the points so its not linear... Also i wondering whether i can get the potential energy, is it possible?
upload_2017-4-8_15-38-27.png
upload_2017-4-8_15-38-59.png
 

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  • #2
rasalzari said:
hen I graphed the average and produced a line of regression, but it didnt pass through the points so its not linear...
That's not necessarily true. You need error bars. Your line may not pass through the average, but does it pass through any of the measured values? Can you estimate what they are? If not, plot all three points instead of the average and see what you get. Also, the angle of launch is critical for the range. What did you do to make sure that the angle was the same in all launches?

Also, your plot is unconventional. The independent variable is on the horizontal axis and the dependent variable on the vertical, not the other way around. For a linear plot it doesn't make much difference, but for other kinds of dependence it could be confusing and disorienting to the viewer.
 
  • #3
kuruman said:
That's not necessarily true. You need error bars. Your line may not pass through the average, but does it pass through any of the measured values? Can you estimate what they are? If not, plot all three points instead of the average and see what you get. Also, the angle of launch is critical for the range. What did you do to make sure that the angle was the same in all launches?

Also, your plot is unconventional. The independent variable is on the horizontal axis and the dependent variable on the vertical, not the other way around. For a linear plot it doesn't make much difference, but for other kinds of dependence, it could be confusing and disorienting to the viewer.
Alright, i will try inputting all the measurements and see what happens, however, i did add the error bars but for some reason, it's only visible when u zoom in. I used ploty https://plot.ly/create/ to get the line of reg.
 
  • #4
kuruman said:
That's not necessarily true. You need error bars. Your line may not pass through the average, but does it pass through any of the measured values? Can you estimate what they are? If not, plot all three points instead of the average and see what you get.
I tried all measurements, it is still not linear. :(

kuruman said:
What did you do to make sure that the angle was the same in all launches?
I think i might have done it wrong :|:cry:
 
  • #5
kuruman said:
That's not necessarily true. You need error bars. Your line may not pass through the average, but does it pass through any of the measured values? Can you estimate what they are? If not, plot all three points instead of the average and see what you get. Also, the angle of launch is critical for the range. What did you do to make sure that the angle was the same in all launches?

Also, your plot is unconventional. The independent variable is on the horizontal axis and the dependent variable on the vertical, not the other way around. For a linear plot it doesn't make much difference, but for other kinds of dependence it could be confusing and disorienting to the viewer.
is it alright if the best line of fit misses the one point? will it considered linear?
 
  • #6
rasalzari said:
is it alright if the best line of fit misses the one point? will it considered linear?
Yes and no. Let me explain. You need to understand how well your theory of linearity matches the experiment that you undertook. "Linear" in your case means that the range is proportional to the stretch for all values of the stretch. So answer me this, why did you start stretching at 0.10 m? What if you started at 0.01 m or 0.001 m?
 
  • #7
Why do you expect a linear relation?
rasalzari said:
Also i wondering whether i can get the potential energy, is it possible?
If you know the launch angle and the projectile mass, you can make some estimate about the kinetic energy of the projectile.
rasalzari said:
however, i did add the error bars but for some reason, it's only visible when u zoom in.
Error bars should be based on the variations between the trials, not based on the measurement uncertainty of the individual launches. Your estimate for the average is much more uncertain than a millimeter.If your measurement uncertainty is really a single millimeter as shown in the table (I doubt that), you should give the measured ranges with one more digit.
 
  • #8
mfb said:
Why do you expect a linear relation?If you know the launch angle and the projectile mass, you can make some estimate about the kinetic energy of the projectile.
Error bars should be based on the variations between the trials, not based on the measurement uncertainty of the individual launches. Your estimate for the average is much more uncertain than a millimeter.If your measurement uncertainty is really a single millimeter as shown in the table (I doubt that), you should give the measured ranges with one more digit.
fixed it, thank you for replying :redface:

kuruman said:
Yes and no. Let me explain. You need to understand how well your theory of linearity matches the experiment that you undertook. "Linear" in your case means that the range is proportional to the stretch for all values of the stretch. So answer me this, why did you start stretching at 0.10 m? What if you started at 0.01 m or 0.001 m?
oh good point, ill try doing it and thank so much!

:oldbiggrin:
 

Related to How stretching a rubber band, affects the range of a shot?

1. How does stretching a rubber band affect the range of a shot?

Stretching a rubber band increases its potential energy, which is then converted into kinetic energy when released. This increase in energy allows the rubber band to propel the object further, resulting in a longer range for the shot.

2. Does stretching the rubber band to different lengths affect the range of the shot?

Yes, the length to which the rubber band is stretched directly affects the range of the shot. The longer the rubber band is stretched, the greater the potential energy and therefore the greater the range of the shot.

3. How does the thickness of the rubber band impact the range of the shot?

The thickness of the rubber band affects the strength of the rubber band, which in turn affects the amount of potential energy it can hold. Thicker rubber bands have more potential energy and can therefore stretch further, resulting in a greater range for the shot.

4. Can the temperature of the rubber band affect the range of the shot?

Yes, the temperature of the rubber band can affect the range of the shot. As temperature increases, the molecules in the rubber band move more rapidly, resulting in a decrease in the rubber band's potential energy. This decrease in energy can lead to a shorter range for the shot.

5. Are there any other factors that can affect the range of a shot using a rubber band?

Yes, there are other factors that can affect the range of a shot using a rubber band. These include the weight and shape of the object being propelled, as well as external forces such as air resistance and wind. The surface on which the object is being shot from can also impact the range of the shot.

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