Union College
MER201– Particle Mechanics
LAB Exercise -Particle Kinematics and Kinetics
In this laboratory exercise we will use direct measurements
and Videopoint to examine the motion of two constrained
particles.
Materials:
You will need to assemble the following equipment: one rod
pulleys, one free pulley, a set of weights, a stop watch, a
vertical force table, a long bar, 2 clamps, and a 2 m length of
string.
Procedure:
Part 1: Analytical Results
Fig 1. Schematic of pulley system to
be studied.
Step 1: Analyze the pulley system shown in Figure 1 by drawing
a free body diagram and a mass acceleration diagram. Calculate the theoretical acceleration
of blocks A and B as a function of the mass of each block. Be sure to note any assumptions
that enter into your analysis.
Part 2: Experimental Results – Force Tables
Step 1: Set up the pulley system shown in Figure 1 using the vertical force tables, pulleys, bars and
weights. Use a 200g mass for Block A and a 300g mass for Block B. Make sure that all
connecting strings are vertical. Maximize the distance traveled by hanging the blocks off the
edge of the table.
Step 2: Using a stopwatch, determine the time for block A to drop to the floor (be sure to record
this distance). Repeat the experiment 10 times, recording both the distance traveled and the
time to drop.
Step 3: Analyze the data from Step 2 by calculating the acceleration of block A for each of the 10
cases. Determine the average acceleration and the standard deviation. Compare your
measured value to the theoretical value.
Step 4: Repeat Steps 1-3 using a 400g mass for Block A and a 500g mass for Block B.
Part 3: Experimental Results - Videopoint
Step 1: Analyze the Videopoint movie 200_300.mov which used a 200g mass at A and a 300g mass
at B. Determine the particle location, velocity and acceleration as a function of time (use
Videopoint to do this) for both blocks. (When you open the movie indicate that you want to
locate 2 features.) Fit your position versus time data to a second order polynomial and
determine the acceleration by differentiating. Note the diameter of the upper pulley is 44
mm. Use this dimension to scale your movie.
Fall 2005
Union College
MER201– Particle Mechanics
Step 2: Analyze the Videopoint movie 400_500.mov which used a 400g mass at A and a 500g mass
at B. Determine the particle location, velocity and acceleration as a function of time (use
Videopoint to do this) for both blocks. (When you open the movie indicate that you want to
locate 2 features.) Fit your position versus time data to a second order polynomial and
determine the acceleration by differentiating. Note the diameter of the upper pulley is 44
mm. Use this dimension to scale your movie.
Discussion Questions
Address the following questions in your lab write up.
1.
2.
3.
4.
How do your measured results compare to the analytical results? How do the different
measurement techniques compare to one another?
How does the acceleration of Block A compare to that of Block B for all of your measured
cases? How should they compare?
Discuss possible errors that could have been introduced into the experiments and how those
errors affect your results.
How do you think friction affects your results?
Lab Report:
You must turn in the attached grading sheet The format for full lab reports can be found on the
course web page. You do not need to write an abstract but you should include all other parts of a
full lab report as indicated on the web page. See the attached grading sheet for guidance.
Student A – Introduction, Procedure and Conclusion
Student B – Results and Discussion
Fall 2005
Union College
MER201– Particle Mechanics
EVALUATION FORM: LABORATORY - Particle Kinematics and Kinetics
Names:
Please attach this to your completed lab report when you pass it in!
CATEGORY
TECHNICAL EVALUATION
Title Page
Was it included?
Was all of the requisite information present?
Introduction
Was it included? Did it properly introduce the lab? Was the objective
stated? Was the rest of the report forecasted?
Experimental Procedures
Was the pulley system used in the lab described?
Was a figure of the pulley system included? Were the weights described?
Was the experimental procedure used to time the blocks explained in
detail?
Was the Videopoint procedure described in detail?
Results
Were the equations of motion for the theoretical system included and
described? Were the free-body and mass-acceleration diagrams included
and properly labeled?
Was a data table for the stop watch measurements included?
Were data tables and plots for the Videopoint measurements included?
Was a summary table of acceleration measurements included?
Discussion
Were the theoretical, stopwatch and Videopoint results discussed? Were
the stopwatch results discussed?
Was the accelerations for Blocks A and B compared?
Were the differences between the experimental and theoretical results
explained?
Were sources of error discussed? Was the effect of friction discussed?
Were any other interesting points about the outcome of the lab discussed?
Were summary figures/tables used to aid the discussion?
Conclusion
Was the objective of the laboratory restated? Were the main results of the
lab summarized? Were recommendations made? Does it concisely
summarize the lab?
Acknowledgments and References
WRITING EVALUATION
Organization
Presentation
Grammar and Spelling
Flow (how well do the two parts fit together?)
TOTAL
Comments:
Fall 2005
Possible
Points
Earned
Points
Responsible
Person
(initial)
5
10
20
15
15
10
5
80
5
5
5
5
100