Projectile Motion Lab
Author: Tegan Durishin
Lab Partners: Anthony Farano & Thatcher David
Date Completed: 22 April 2014
Author: Tegan Durishin
Lab Partners: Anthony Farano & Thatcher David
Date Completed: 22 April 2014
Purpose
The purpose of this lab is to determine the location of the landing of a metal ball. The ball is launched at an upwards angle off of a platform higher than the ground on which it will land.
Theory
The diagram shown here portrays our experiment in which a projectile was launched from an elevated platform at a positive angle.
Equation for time:
Equation for range:
Experimental Technique
For this experiment you will need a mini metal ball launcher, launcher brackets and clamps, a steel or glass ball, Photogates, a photogate bracket, a plumb bob, a measuring tape, target paper and carbon paper. First, we set up the launcher to launch at an angle. Next, we used two photogates to measure the initial launch velocity of the ball. Each member of the group used a different launch speed at the same angle. When launching, we fired ten times and determined the average velocity. After this, we measured the initial launch height of the ball. To do this, we measured from the floor to the bottom edge of the ball pictured on the side of the launcher using a measuring tape. We used the bottom edge because it is this edge that will make the mark on the target. Then, we predicted the range of the projectile. In order to make this prediction, we needed to derive an equation for range in terms of the initial velocity and the launch height. We used a plumb bob to mark the initial launch position on the floor, and taped an index card under the launch position and placed our mark on the card. Finally, we placed our targets at the predicted ranges and fired ten shots each and measure the average range.
Data
Predicted Range: Initial Velocity:
2.475 m 4.14 m/s
Calculated Average Range: Change in (Y):
2.4857 m .963 m
Analysis
Predicted Range:
Average Range:
Percent Difference:
Uncertainty:
Conclusion
In this lab we determined where a metal ball, shot from an elevated platform at an upwards angle, will land on the ground. Through forming large equations I found that my ball will land 2.475 meters from where it was shot. However, during testing, I found that the ball landed in various different locations that were relatively close, but not precise and consistent. This is because the launchers that were used do not launch the metal ball with the same force and air pressure each time. I noticed this same error while finding the initial velocity since I would not receive a constant velocity so instead I averaged the amounts which results in a non exact answer. I believe that wind resistance is not a factor within this experiment. Although it may be slightly present due to air conditioning, it is not great enough to affect the results of the launches. My launches particularly were near the mark of 2.475 meters but were just longer than expected with the average being 2.4857 meters, +.0107 meters over predicted. The total uncertainty of the range measurement is +/- .01m, a very minute amount.