Eastern Mediterranean University
Department of Mechanical Engineering
Laboratory Handout
COURSE:
RIGID BODY Dynamics (MENG 233)
Semester: Spring (2014-2015)
Name of Experiment: Conservation of Momentum
Instructor: Assis. Prof. Dr. Mostafa Ranjbar
Assistants: Sadegh Mazloomi
Submitted by:
Student No:
Group No:
Date of experiment:
Date of submission:
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EVALUATION
Activity During Experiment & Procedure
30 %
Data , Results & Graphs
35 %
Discussion, Conclusion & Answer to Questions
30 %
Neat and tidy report writing
5%
Overall Mark
Name of evaluator: Milad Kermani
1.
OBJECTIVES
The aim of the experiment is to observe the conservation of momentum experimentally.
2.
APPARATUS
Data collector, two motion sensors, horizontal track, two carts.
Figure 1: collision set-up
3.
THEORY
How is it possible for two carts to collide head-on and come to a complete stop? Why is it
that when a heavy vehicle collides with a lightweight vehicle, the two of them continue in
the general direction the heavy vehicle was going before it collided?
Collisions between objects—whether locomotives shopping carts, or your foot and the
sidewalk—can be complicated. Yet even in the most chaotic of collisions, as long as
there are no external forces acting on the colliding objects, one principle always holds
and provides an excellent tool for understanding the dynamics of the collision. That
principle is called the conservation of momentum. When studying the effect of car
slamming into a train we say the car had an inelastic collision because the car stayed in
contact with the train after the collision. If the car had bounced off the train then an
elastic collision would have occurred.
4.
WORK TO BE CARRIED OUT
Set up the equipment as shown in the figure 1. Place the track on a horizontal surface.
Level the track by placing a cart on the track. If the cart rolls one way or the other, use
the adjustable foot at one end of the track to raise or lower that end until the track is level
and the cart will not roll one way or the other. Adjust each sensor so it can measure the
motion of a cart as it moves from the end of the track to the middle and back again. Add a
250-g mass to each cart and measure the total mass of each cart. Record their masses in
the data table on the Student Response Sheet. Place Mass Cart 1 on the left side of the
track. Place Mass Cart 2 on the right side of the track. Turn the carts so the Velcro on
each car will stick together when the carts collide. Measure the velocity of both cart
before and after the collision and record the dat. Find the initial and final momentum as
well as right before and after the strike. Iterate the experiment to higher the preciseness of
your data.
m1(v1)1 + m2(v2)1 = m1(v1)2 + m2(v2)2
(1)
5.
EXPERIMENTAL DATA
Before Collision
Velocity
Iteration
Cart 1
Cart 2
After Collision
Momentum
Cart 1
Cart 2
Velocity
Cart 1
Cart 2
Momentum
Cart 1
One
Two
Three
Table1: Observed and recorded data
6.
Vocabulary
Use available resources to find the definitions of the following terms:
Elastic collision:
Inelastic collision:
Momentum:
7.
DATA ANALYSIS
Check the observed data by the aid of equation one. Uncertainties should be taken into
account to have the preciseness and error analysis in your reports. Write the error
analysis.
8.
GRAPH
Plot the graphs of velocity and momentum of each cart once separately and once all
together versus time.
Cart 2
9.
ANSWER THE FOLLOWING QUESTIONS
-
What can you conclude about the relationship between the momentum before and
after an inelastic collision?
-
-
Do your results support your predictions?
-
How the momentum equation is created?
-
How the momentum conservation is created?
-
Explain the reason why a spaceship can start flying and leave the earth through
conservation of momentum concept.
10. DISCUSSION, CONCLUSION & ANSWER TO QUESTIONS
State your observation during the experiment. Support your memo by mentioning the
error sources which affect the accuracy of results and analysis.