Analysis

For the most part, the data seems to support my hypothesis. As the distance between the rifle and the target increase, the calculated velocity of the object decreases at a steady rate. Except for the outlier at distance 3 meters, the graph seems to follow a linear path. Although 3 meters seemed to have the highest velocity, this can be attributed to a number of unknowns and uncertainties. Because the experiment was outdoors, the apparatus was always subject to sudden wind gusts. Also, the estimation of the horizontal distance was questionable. The estimation could only truly be accurate up to half a centimeter, and considering how close the results for each distance were, this may have skewed results considerably. Other sources of error include the box having lost some (although little) bits of mass, when I failed to hit the target directly. This resulted in the box tearing, and loss of some mass. Also, again when the target was not hit directly in the center, this may have caused some degree of shaking, which lessens the amount of energy that is used to propel the swing of the pendulum.

If this experiment were to be conducted again, there are many factors that could easily be controlled. Running the experiment indoors would eliminate much of the unknown uncertainties, although for safety’s sake, my experiment had to be conducted outdoors. Securing the pendulum with two sticks would also have helped contain the stability, preventing any shaking. Longer and lighter sticks, as well as a lighter target, would allow the pendulum to swing a greater distance, and thus accentuating data, and lessening the significance of uncertainties in measuring. But most importantly, if I were to do this experiment again, I would especially try to increase the distance between the target and rifle even farther. Obviously, as the distance increases, the air resistance becomes greater, and would again accentuate the data. To make this possible, a scope or other targeting devices on the rifle may be necessary, as shooting farther away from 5.3 meters has proven difficult.

Conclusion: Except for a single hiccup in the data, the data generally supports the original hypothesis well.

 

Bibliography (links)

Falling Objects and Air Resistance: Site with information on Air Resistance by Tom Benson.

Newton's Second Law: Site with information on Newton's Second Law of motion by Tom Henderson.

History of Ballistics: A history of ballistics by Mathew Mosdell.

Ballistic Pendulum: Info on how to calculate Ballistic Pendulum stuff.

Crosman Airguns: A good place to purchase an air rifle, or find information on my personal rifle. I have a Crosman 764SB, rated at 625 FPS. I think my data is more or less close (keep in mind my data is in meters).