2D Motion Rocket Challenge

Rocket Challenge Blog

     The purpose of this challenge was to predict how far a rocket launched at a certain angle would travel in the horizontal direction. Our group decided to set our rocket at an angle of 50 degrees, which  we thought would launch reasonably far. Here is a diagram of what our setup looked like:

     Once we had raised enough air pressure via a bike pump, our rocket would launch. To maintain a constant initial velocity, we had to make sure and fit the pressure cap on very tightly each and every time. After a few tests with our rocket at a 30 degree angle (we weren't allowed to test within 10 degrees of 50 degrees), we collected enough data to start making our predictions for where our rocket would land. Coming into class the next morning we discovered that because our angle of launch was reversed, we had been calculating our predictions based on the completely opposite angle. Learning from this mistake, our group finally made progress.

     Starting with our 30 degree info, we found the V(initial x) to be 12.57 m/s using the formula v = (change in) x / time. We then went ahead, using cosine, and found the V initial to be 25.14 m/s. Because our rocket's initial velocity would always stay the same no matter the angle that we launch it at, we had found the piece of info crucial to making our prediction. Keeping 25.14 m/s as the initial velocity, we changed the angles to 50 and 40 degrees. Using cosine, we found both the V(initial x) and the V(initial y). These were 19.26 m/s and 16.16 m/s respectively. We could then use the equation (change in) x = 1/2at^2+v(initial)*t  to find time. This involved setting up the quadratic formula, which eventually gave us the answer of t = 3.232 seconds. Using this, we plugged it into the equation v = (change in) x / time, which gave us our final prediction of 62.25 meters. This meant that, based on our calculations, our rocket would land at a distance of 62.25 meters away from the starting point. This information is summed up below in the data table:

     Unfortunately for us, our group completely forgot about timing our test launch at 50 degrees. When we did launch it, it landed roughly 20 meters short of our predicted landing zone. I say 'roughly' 20 meters because we didn't measure our actual distance because there was only one measuring tool being shared among all the groups. However, using the rough 20 meters short estimate our group found our percent error to be about 47% off. My hypothesis for why this number is so high is because we might've taken inaccurate measurements of time when launching our rocket at a 30 degree angle. This would mean that all of our calculations from that point on got more skewed as we went along, eventually leading us 47% off-course. If we were to redo this experiment, we would take our data much more carefully than this time around. Overall, this was a fun way to visually play with the skills we've learned so far this year in physics.