Lab Report 5-physics PDF

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Lab Report 5: Projectile Motion

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Section 05: Three Views of a Projectile Ball

University of Texas at El Paso

Lab Report 5: Projectile Motion

2 Introduction

A projectile is when an object is dropped and the only force acting upon it is the force of gravity (Phys. Class 1). In this lab, the projectile motion of a ball being tossed in the air will be examined. Using three perspectives, a drone looking downward, a camera pointing directly and a camera aimed perpendicular to the plane of the motion, will allow us to analyze the vertical and horizontal motion of the ball separately (Pivot 5). Materials and Setup ● Pivot Interactions ● Calculator ● Stopwatch ● Ruler Pivot Interactions has a video that shows the three views of a Projectile Ball. This video will be used to examine all views and explore two-dimensional “projectile” motion. Procedure To begin this experiment I first watched the video of the ball from 3 perspectives at the same time to determine how I would set up the rulers on the screen. The horizontal ruler was placed on the top view to measure the horizontal positions of the ball starting from right before the ball is going to leave the girl’s hands. The vertical ruler was placed on the vertical perspective and the 0cm was also placed right before the ball left her lands. The stopwatch was placed and reset until Frame 1 was the moment the ball left the girls hands. The time and position of both horizontal and vertical positions were measured in equal time intervals. These

Lab Report 5: Projectile Motion

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values were graphed and using a calculator the slope between 3 points was measured and recorded to get a velocity vs time graph for the vertical perspective. Data and Data analysis

Figure 1 Horizontal Position vs Time Graph

Lab Report 5: Projectile Motion

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Figure 2 Vertical Position vs Time

Figure 3 Vertical Velocity vs Time

Figure 1 shows the horizontal position of the ball as time increases. As time is increasing the position of the ball is moving further away from the starting point horizontally. Figure 2

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shows us the position (vertically) of the ball as it is thrown up. In the graph, we can see that as it leaves the girl’s hands it is getting further away from her but it reaches its max point and drops to the ground below the starting height it was thrown at. We know this because the graph goes into the negative and the x-axis (zero) is the starting height of the ball. Figure 3 shows the vertical velocity of the projectile ball. The graph's acceleration is negative and crosses the x axis. When it crosses the x-axis this shows us that at some point the ball's acceleration was zero. This point is at the ball's highest point because when the ball reached the highest point it stayed at the top for about .10 seconds and then fell back down with the force of gravity.

Conclusion In this lab, we were able to see the projectile motion of a ball from three different perspectives. Using the horizontal and vertical perspectives and graphing them we could also gain an understanding of the complete motion of the ball if the third perpendicular perspective didn’t exist. The maximum height of a projectile is known as the apex of its motion and at this point the velocity of the ball is zero. Because the velocity is zero this also means that the acceleration was zero at the max height. After the apex, a projectile is now a free-falling object falling in the vertical direction with a velocity of 9.81 m/s. Personal Learning Experience This lab taught me about the free-fall of an object and it will always be going at the same speed of 9.81 m/s. I always thought that if you had, for example, a brick and a feather dropped down from the same height the brick would fall faster because its heavier but in reality, they will

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fall at the same speed because of the force of gravity. Because of this lab, I will be able to project the motion of objects in life when they are free-falling.

Lab Report 5: Projectile Motion

7 References

"Section 5." Pivot Interactives. Accessed June 19, 2020. https://app.pivotinteractives.com/assignments/5ec5b1bb04b6cd00201d00cd/responses. Projectile motion instructions "What Is a Projectile?" The Physics Classroom. Accessed June 19, 2020. https://www.physicsclassroom.com/class/vectors/Lesson-2/What-is-a-Projectile....