Lab
Freefall: Timing a Bouncing Ball
Printer Friendly Version
Procedure
For this lab, two students will form a team. The first student will use a stop watch to time the number of seconds between bounces while the second student will be the observer of how high the ball bounces. When the balls is dropped, the student with the stop watch listens for the sound of the first bounce, starts the stop watch, and then listens for the sound of the second bounce, when he immediately stops timing. The second student observes how high the ball bounces against the backdrop of the wall. To assist with calculating the height of the bounce, there are colored strips (green, orange, yellow pink), each 10-cm wide numbered in 6 sets of four. Once the height and hang time for a bounce are recorded in the data chart, we repeat the process for a total of five trials.
The purpose of this lab is to experimentally calculate the acceleration due to gravity. If you examine each bounce, you will notice that the net vertical displacement equals zero. This tells us that the time for the ball to rise to its apex is exactly equal to the time it takes the ball to fall back to the ground. We also know that the instantaneous vertical velocity at the apex equals zero and the height of the apex.
Calculate the acceleration due to gravity by using the kinematics equation s = v
_{o}
t + ½at
^{2}
and isolate the second half of the golf ball's bounce. Since you could only estimate the height of each apex to the nearest 0.05 meters, you should express the value for your experimental “g” to only two decimal places.
v
_{o}
= 0
s = -height of bounce
t = ½ (the total time on your stopwatch)
For each trial, place the results of your measurements of time and height as well as your calculated experimental value for “g” in the data table provided.
Data Table
hang time
between bounces
height
of apex
experimental
"g"
Trial
(sec)
(meters)
(m/sec
^{2}
)
1
2
3
4
5
Conclusions
What is your group's average experimental value for "g" based on all 5 trials?
Using your average experimental value for "g", calculate a percent error against the accepted value for the acceleration due to gravity at sea level, -9.81 m/sec
^{2}
.
Which aspect of the data collection had the least precision: the timing or the ball's height measurement? Support your choice.
How should the ball’s impact velocity when it first strikes the ground at the start of the bounce compare to its final impact velocity when it strikes the ground at the conclusion of the bounce? Support your answer.
Why did the ball
not
bounce back up to the height from which it was originally released?
The coefficient of restitution is a measure of the speed of separation to the speed of approach in a collision. In our lab, it can be calculated as the ratio of |v
_{o}
| for the ball rising to the apex divided by |v
_{f}
| for the ball falling from its initial release off the roof.
You are to calculate the coefficient of restitution for the third ball. Use the fact that the ball was originally released from rest off of the roof which was 5.14 meters above the ground. The height of the apex is recorded in your table. For this calculation use the accepted value of the acceleration due to gravity, g = -9.81 m/sec
^{2}
. This coefficient has no units.
Refer to the following information for the next three questions.
Which of the graphs displayed above correctly illustrates the ball’s position vs time between its two impacts with the ground?
Which of the graphs displayed above correctly illustrates the ball’s velocity vs time between its two impacts with the ground?
Which of the graphs displayed above correctly illustrates the acceleration experienced by the ball between its two impacts with the ground?
A team may submit its data report online together. No papers need to be turned in to the one-way box for this lab.
Related Documents
Lab:
Labs -
A Photoelectric Effect Analogy
Labs -
Acceleration Down an Inclined Plane
Labs -
Ballistic Pendulum: Muzzle Velocity
Labs -
Coefficient of Friction
Labs -
Collision Pendulum: Muzzle Velocity
Labs -
Conservation of Momentum
Labs -
Cookie Sale Problem
Labs -
Flow Rates
Labs -
Freefall Mini-Lab: Reaction Times
Labs -
Galileo Ramps
Labs -
Gravitational Field Strength
Labs -
Home to School
Labs -
InterState Map
Labs -
LAB: Ramps - Accelerated Motion
Labs -
LabPro: Newton's 2nd Law
Labs -
LabPro: Uniformly Accelerated Motion
Labs -
Mass of a Rolling Cart
Labs -
Moment of Inertia of a Bicycle Wheel
Labs -
Monkey and the Hunter Animation
Labs -
Monkey and the Hunter Screen Captures
Labs -
Projectiles Released at an Angle
Labs -
Ramps: Sliding vs Rolling
Labs -
Range of a Projectile
Labs -
Roller Coaster, Projectile Motion, and Energy
Labs -
Rube Goldberg Challenge
Labs -
Target Lab: Ball Bearing Rolling Down an Inclined Plane
Labs -
Terminal Velocity
Labs -
Video LAB: A Gravitron
Labs -
Video Lab: Ball Bouncing Across a Stage
Labs -
Video LAB: Ball Re-Bounding From a Wall
Labs -
Video Lab: Cart Push #2 and #3
Labs -
Video Lab: Falling Coffee Filters
Labs -
Video Lab: Two-Dimensional Projectile Motion
Resource Lesson:
RL -
Accelerated Motion: A Data Analysis Approach
RL -
Accelerated Motion: Velocity-Time Graphs
RL -
Analyzing SVA Graph Combinations
RL -
Average Velocity - A Calculus Approach
RL -
Chase Problems
RL -
Chase Problems: Projectiles
RL -
Comparing Constant Velocity Graphs of Position-Time & Velocity-Time
RL -
Constant Velocity: Position-Time Graphs
RL -
Constant Velocity: Velocity-Time Graphs
RL -
Derivation of the Kinematics Equations for Uniformly Accelerated Motion
RL -
Derivatives: Instantaneous vs Average Velocities
RL -
Directions: Flash Cards
RL -
Freefall: Horizontally Released Projectiles (2D-Motion)
RL -
Freefall: Projectiles in 1-Dimension
RL -
Freefall: Projectiles Released at an Angle (2D-Motion)
RL -
Monkey and the Hunter
RL -
Summary: Graph Shapes for Constant Velocity
RL -
Summary: Graph Shapes for Uniformly Accelerated Motion
RL -
SVA: Slopes and Area Relationships
RL -
Vector Resultants: Average Velocity
Review:
REV -
Test #1: APC Review Sheet
Worksheet:
APP -
Hackensack
APP -
The Baseball Game
APP -
The Big Mac
APP -
The Cemetary
APP -
The Golf Game
APP -
The Spring Phling
CP -
2D Projectiles
CP -
Dropped From Rest
CP -
Freefall
CP -
Non-Accelerated and Accelerated Motion
CP -
Tossed Ball
CP -
Up and Down
NT -
Average Speed
NT -
Back-and-Forth
NT -
Crosswinds
NT -
Headwinds
NT -
Monkey Shooter
NT -
Pendulum
NT -
Projectile
WS -
Accelerated Motion: Analyzing Velocity-Time Graphs
WS -
Accelerated Motion: Graph Shape Patterns
WS -
Accelerated Motion: Practice with Data Analysis
WS -
Advanced Properties of Freely Falling Bodies #1
WS -
Advanced Properties of Freely Falling Bodies #2
WS -
Advanced Properties of Freely Falling Bodies #3
WS -
Average Speed and Average Velocity
WS -
Average Speed Drill
WS -
Charged Projectiles in Uniform Electric Fields
WS -
Chase Problems #1
WS -
Chase Problems #2
WS -
Chase Problems: Projectiles
WS -
Combining Kinematics and Dynamics
WS -
Constant Velocity: Converting Position and Velocity Graphs
WS -
Constant Velocity: Position-Time Graphs #1
WS -
Constant Velocity: Position-Time Graphs #2
WS -
Constant Velocity: Position-Time Graphs #3
WS -
Constant Velocity: Velocity-Time Graphs #1
WS -
Constant Velocity: Velocity-Time Graphs #2
WS -
Constant Velocity: Velocity-Time Graphs #3
WS -
Converting s-t and v-t Graphs
WS -
Energy Methods: More Practice with Projectiles
WS -
Energy Methods: Projectiles
WS -
Force vs Displacement Graphs
WS -
Freefall #1
WS -
Freefall #2
WS -
Freefall #3
WS -
Freefall #3 (Honors)
WS -
Horizontally Released Projectiles #1
WS -
Horizontally Released Projectiles #2
WS -
Kinematics Along With Work/Energy
WS -
Kinematics Equations #1
WS -
Kinematics Equations #2
WS -
Kinematics Equations #3: A Stop Light Story
WS -
Lab Discussion: Gravitational Field Strength and the Acceleration Due to Gravity
WS -
Position-Time Graph "Story" Combinations
WS -
Projectiles Released at an Angle
WS -
Rotational Kinetic Energy
WS -
SVA Relationships #1
WS -
SVA Relationships #2
WS -
SVA Relationships #3
WS -
SVA Relationships #4
WS -
SVA Relationships #5
WS -
Work and Energy Practice: An Assortment of Situations
TB -
2A: Introduction to Motion
TB -
2B: Average Speed and Average Velocity
TB -
Antiderivatives and Kinematics Functions
TB -
Honors: Average Speed/Velocity
TB -
Kinematics Derivatives
TB -
Projectile Summary
TB -
Projectile Summary
TB -
Projectiles Mixed (Vertical and Horizontal Release)
TB -
Projectiles Released at an Angle
TB -
Set 3A: Projectiles
PhysicsLAB
Copyright © 1997-2016
Catharine H. Colwell
All rights reserved.
Application Programmer
Mark Acton