Science Buddies: "Ask an Expert"

[Administrator note: posting on behalf of student]

Project: https://www.sciencebuddies.org/science- ... background
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I need help with two things that I don't really understand from this project.

Firstly, If I wanted to do this project with the launch angle as the sole independent variable, should I keep the pull-back angle constant for all my trials? Because if I do this, the length of the rubber band when stretched (x1) and before the ball launches (x2) would be constant. So how do you plug this into the equation 16 that's found in the background? Is it fine if x1 and x2 never change?

Secondly, If I instead wanted to make the pull-back angle the independent variable, what equations could I use to theoretically see how the pull-back angle affects the trajectory of the ball?

Hello,

This sounds like a fun project! By keeping the launch angle as the sole independent variable there is no problem using equation 16 if x1 and x2 never change. Conversely, if you instead wanted to make the pull-back angle the independent variable you'll need to rearrange equation 16 to solve for this variable instead of launch angle.

Good luck!

Audrey