Author: Alyssa Jordan
Partner: Julia Fisher & Kirsten LeVan
Date: October 20, 2015
Partner: Julia Fisher & Kirsten LeVan
Date: October 20, 2015
Projectile Motion
Purpose
The purpose of this lab is to investigate projectile motion by determining the initial velocity of the ball as it is launched and predicting the projectile's range.
Theory
Experimental Technique
An angle of launch will be decided upon. We will use two photogates attached to the launcher to measure the initial velocity. The ball will be launched ten times and average of the initial velocities will be determined. Then, we will measure the initial launch height using a measuring tape. Using this information, we will derive equations to figure out the range. The range will then be measured out using a measuring tape, and the thick middle line on the paper will be placed where the predicted range is. A piece of carbon paper will be used to mark the landing points and the projectile will be launched ten more times. The average range and the actual range will be compared and the percent difference will be determined.
Data
Initial Launch Height: 1.3012m
Analysis
Conclusion
During this lab, we calculated the range of a projectile by deriving various equations. After calculations were completed, I determined the range should be 2.597m. However after launching the projectile ten times, I found that my average range was 2.726m with a uncertainty of plus or minus .0135m. Compared to my predicted range, my average range was only .129m off and had a percent difference of 4.847%. One source of error in this experiment is the initial velocity is not always constant; it slightly varies depending on how hard one pulls the trigger. Also, parallax can be a source of error. The student must set the launcher at the correct angle, place the center of the paper at the correct range, and determine the distance of the marks. These can all be affected by parallax. The tape measure also only measure up to the tenths place in centimeters. This means we were forced to make estimations of the hundredths place. Wind resistance could be a source of error because the school's heating/cooling system was on during the experiment. However, I do not believe it caused much of an effect based on how close to the predicted range the actual ranges were.
References
Bowman, Doug. "Projectile Motion Lab." Lahs Physics. Web. 20 Oct. 2015. <http://lahsphysics.weebly.com/projectile-motion-lab.html>.