PHYS172-S22-Lab10-Final

pdf

School

Purdue University *

*We aren’t endorsed by this school

Course

172

Subject

Physics

Date

Apr 3, 2024

Type

pdf

Pages

Uploaded by EarlExplorationRaven41

PHYS 172 LAB 10: Energy Analysis of Collisions Spring 2022 LAST NAME (ALL CAPS) CYZE FIRST NAME (ALL CAPS) DANIEL PUID: 33226588 LAB GROUP (TABLE) #04 LAB DAY: WEDNESDAY LAB TIME: 1:30-3:20 LAB ROOM: 008 The goal of this lab is to: ● Determine the coefficient of restitution of the ball bouncing off the floor. ● Program and analyze the motion an object that bounces off the ground. Introduction One quantity that is used to describe the effect of a collision of two objects is called Coefficient of Restitution . It is the ratio of the speed of an object after and before the impact. The larger this coefficient is for a given object, the closer to elastic is the collision. Coefficient of restitution is an empirically determined quantity and depends on a wide range of properties of both objects. PASCO Experiment Take a video (on a cell phone) of a ball falling vertically from about 1.5-2.0 m and bouncing off the floor. The procedure here is the same as for Lab 08: - Take a ball from your TA and the 2-meter wooden stick. - Go to the hallway and find a clear background for your video. - Record from about the midpoint of the height from which your group will drop the ball. - Save the video on your phone and upload it to your lab PC. - Open PASCO Capstone and Video Analysis. - Upload the video you recorded. Set the Graph axes to Object #1 → vy, Object#1 (m/s) and Time (s) . Add another Graph and set its axes to Object #1 → y, Object#1 (m) and Time (s) . Make appropriate alignment for your video recording: - Y-axis should point in the vertical direction of your video recording. - X-axis should point in the horizontal direction of your video. - If your camera was slightly tilted during the recording, then the Coordinate axes will be tilted too. - Pace the ends of Calibration Tool exactly at the ends of the meter stick. - Set the length of Calibration Tool to 2.0 m (the length of the meter stick) for proper scaling. Analyze the video and build a motion graph of the ball (its Y-velocity vs time): - Click on the video display at the center of the ball. - Click the second time and so that a cross point appears. - Click at the center of the ball every frame until it bounces at least 3 times . - Scale your Graph using the Scaling tool for clear visual representation. - Smooth your Graph using the Smoothing tool for better visual representation. When you are done, your Capstone page should look similar to the sample below.

2 [Delete the image above, take a snapshot of your graph and attach it instead] To find the Coefficient of Restitution ( COR ) we need to calculate the ratio between the speed immediately after the collision 𝑣 ? over the speed immediately before the collision 𝑣 ? : COR = | 𝑣 ⃗ ??𝑡?𝑟 | | 𝑣 ⃗ ???𝑜𝑟? | . Read the velocities before and after each rebound in the graph of Velocity vs Time and calculate the COR for each rebound in the table provided below. The COR is a positive number, and its possible values are COR ≤ 1 ; therefore, if your calculated COR is greater than 1, review your data and calculation. Bounce # 1 2 3 4 |𝑣 ???𝑜𝑟? | -5.1 -3.67 -2.24 - |𝑣 ??𝑡?𝑟 | 3.6 2.8 1.61 - COR 0.706 0.763 0.719 - 0.729 Q1: What is the mean value of the COR for your bouncing ball? The mean value for the COR for the bouncing ball is 0.729.

3 VPython Simulation Create a new program named “Lab 10 Program”. Copy and paste the code for today’s lab from: https://glowscript.org/#/user/phys172vpython/folder/S22/program/Lab10Program In addition to the familiar Position Update (line 40), this program contains an if-else statement (lines 35 – 39): - It allows the program to make decisions based on logical conditions. - The condition in "else" is assumed to be the opposite of that of "if". - It follows the same indentation rules as while loops. Q2: Why do we need an if-else statement in this program? Describe in your own words. Provide your best guess. We need an if-else statement to change the momentum of the ball based on if the ball is falling or if the ball is colliding with the ground. If the ball is colliding with the ground, then the momentum of the ball will change to upward. It tells the program when the ball bounces back up. Q3:In line 36, where we are computing the effect of bouncing, why do we need the minus “ - “ sign? A minus sign is needed here because the ball is going to bounce up which is the opposite way of it falling. This minus sign will keep the same momentum of the ball but apply it in the opposite direction. Now you will modify the provided code to account for the coefficient of restitution ( COR ) of the ball when it bounces off the floor. Currently, it is set to 1. Change it to the value you obtained experimentally in the previous part of this lab. Run your program. Observe the Position and Velocity graphs. Q4: In what ways if any are these plots similar to the PASCO graphs? Explain. These graphs have very similar shapes because the velocity of the ball falling will be negative and then will become positive when it bounces back up. The velocity and the position of the ball decrease after each bounce. Q5: In what ways if any are these plots different from the PASCO graphs? Explain. One way that these plots are different is that the plots in the PASCO experiment, the plots are not perfectly straight and there are small imperfections. In the VPython experiment, the ball is falling in perfect conditions while in the PASCO experiment, some energy is lost to heat and sound. Change the code to calculate the potential energy (line 42) and plot the results versus time (line 48, but you don’t have to edit it). Describe what you see in your potential energy plot. [Remember: Potential Energy (of the Ball-Earth System) is: 𝑈 = 𝑚𝑔𝑦 where 𝑦 is coordinate of the center of mass of the ball (above the floor)]. Modify the code to include kinetic energy (line 43) and plot the results to the same graph as potential energy (line 49, but you don’t have to edit it) . Describe what you see. [Remember: Kinetic Energy 𝐾 = 1 2 𝑚𝑣 2 , where 𝑣 is the speed (i.e. the mag nitude of the velocity) of the ball]. Q6: In what ways, if any, are these graphs consistent with the Energy Principle as it applies to the Ball-Earth system? These graphs are consistent because the gravitational potential energy of the ball plus the kinetic energy of the ball equals the total energy of the system. The total energy only decreases because the ball loses some energy due to other internal energies such as heat and sound. To share your program, navigate to your PUBLIC folder containing your “Lab0 9 Program” and provide its URL below: https://glowscript.org/#/user/daniel.cyze/folder/MyPrograms/

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

4 End of Lab CLEAN UP AFTER YOU ARE DONE – 5 POINTS. Please take a photo of YOUR Lab Table showing that it’s clean after you are done and attach it below. Your photo should clearly show your Table # . Make sure you put the meter stick back to its place and returned the ball to your TA. Don’t forget any of your personal belongings. An example photo is provided below. DELETE THE PHOTO ABOVE [PASTE YOUR PHOTO HERE] Group Members’ Signatures (Make sure all sign off on work) Lab TA Signature (GTA or UTA) BEFORE LEAVING Each person in the group must get the signatures of all group members and a TA in the boxes on the left. Upload the completed file (in PDF format) to Brightspace by 11:59 PM SATURDAY Daniel Cyze Neha zaidi Vishnu Krishnan

Related Documents

AP Physics 1 Vectors Projectiles Bull's Eye.pdf

PHYSICS LAB 4 REPORT !.docx

PHYSICS LAB DUE 30TH.pdf

Lab5_Momentum copy.docx

Lab3_Kinematics phy.docx

PHY 1951 LAB Position^J velocity and acceleration L2.pdf

LU10_Bending of Light.docx

Chapter 6_ Conservation of Momentum in 1D.pdf

PHYS182B_196L_ Lab 2 - Electrostatic Charges UPDATED-1-1-1 (1).docx

LU3_Electric Charges and Fields-1.docx

Physics Current Event.pdf

Lab Motion on Incline_LAB.docx

Recommended textbooks for you

Glencoe Physics: Principles and Problems, Student...

Physics

ISBN:9780078807213

Author:Paul W. Zitzewitz

Publisher:Glencoe/McGraw-Hill

Physics for Scientists and Engineers: Foundations...

Physics

ISBN:9781133939146

Author:Katz, Debora M.

Publisher:Cengage Learning

Inquiry into Physics

Physics

ISBN:9781337515863

Author:Ostdiek

Publisher:Cengage

Principles of Physics: A Calculus-Based Text

Physics

ISBN:9781133104261

Author:Raymond A. Serway, John W. Jewett

Publisher:Cengage Learning

Physics for Scientists and Engineers, Technology ...

Physics

ISBN:9781305116399

Author:Raymond A. Serway, John W. Jewett

Publisher:Cengage Learning

University Physics Volume 1

Physics

ISBN:9781938168277

Author:William Moebs, Samuel J. Ling, Jeff Sanny

Publisher:OpenStax - Rice University

SEE MORE TEXTBOOKS

Recommended textbooks for you

Glencoe Physics: Principles and Problems, Student...
Physics
ISBN:9780078807213
Author:Paul W. Zitzewitz
Publisher:Glencoe/McGraw-Hill
Physics for Scientists and Engineers: Foundations...
Physics
ISBN:9781133939146
Author:Katz, Debora M.
Publisher:Cengage Learning
Inquiry into Physics
Physics
ISBN:9781337515863
Author:Ostdiek
Publisher:Cengage
Principles of Physics: A Calculus-Based Text
Physics
ISBN:9781133104261
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Physics for Scientists and Engineers, Technology ...
Physics
ISBN:9781305116399
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
University Physics Volume 1
Physics
ISBN:9781938168277
Author:William Moebs, Samuel J. Ling, Jeff Sanny
Publisher:OpenStax - Rice University