Purpose: The purpose of this lab was to define what the initial velocity of the ball when it is launched out of the pipe. Our next objective is to determine at what angle that the ball will be ejected at the maximum range. Lastly, we predict and confirm the range before we launch the ball at a certain angle.
Theory: Projectile motion according to Dr. James S. Walker is defined as, “the motion of objects that are initially launched –or “projected”- and that then continue moving under the influence of gravity alone” (82). Gravity is the lone force acting on the projectile when in motion. There are two components to a velocity vector. The horizontal velocity component is the effect it has on moving the projectile horizontally. On the other hand the vertical component affects the velocity by moving the projectile vertically.
Procedure: To begin the lab set the launcher to a medium range setting. We used carbon paper on top of white paper to determine where the ball lands on the floor. We then shot the ball at angles of 30, 35, 40, 45, and 50 degrees. We recorded the distances after each shot and determined that shooting the ball at 40 degrees gave us the maximum range. We kept the launcher at a medium setting and shot the ball straight out 5 times and determined what the average range was at this degree. We used that data to determine that the initial velocity was 4.627 m/s. Next we chose our own angle which was 22 degrees and predicted that the range would be 2.57 meters. We then shot the ball 5 times and determined the average range of flight was 3.03 meters.
After shooting the ball straight out 5 times we found the average range which was 2.2794 meters (our delta x value). We then measured the vertical distance that the ball falls which is 1.19 meters (our delta y value). We plugged in the values for the equation:
We determined that the initial velocity= 4.627 m/s
Range at angle theta:
Analysis: Since we found the initial velocity we can use this for all trials because under normal conditions the initial velocity will remain the same. Our percent deviation for this experiment was 15%. If we were to double the velocity it would quadruple the range. If we were to increase the height of the lab stool twice as high it would increase the range by roughly 50%.
Conclusion: In lab 4 we experimented with projectile motion which is the motion of an object that has been launched into movement by a force such as throwing or using a machine. We used the data we gathered from this experiment to predict an average range for an angle we picked and we were not very far off from the real numbers. Air resistance, percent error, and measurements are things to keep in mind when considering what could have caused errors with our predictions for the range.