Writing Homework Help

Purpose: To explore conservation of momentum in a lab
setting

Introduction to the variables and equations:

Basic equation for momentum of a single object:

Subscripts o and f can be included in the equation to represent initial (before collision) and
final (after collision) values. Subscripts 1 and 2 can be included to represent mass 1 and mass 2.

Specific equations for initial and final momentum of mass 1 and mass 2:

Initial momentum
for mass 1: p_1o =
m₁v_1o

Initial momentum for mass 2: p_2o =
m₂v_2o

Final momentum for mass 1:
p_1f =
m₁v_1f

Final momentum for mass 2:
p_2f =
m₂v_2f

Initial momentum total and final momentum total can also be calculated by taking the sum of the momentum values
for each cart.

Total momentum equations:

Initial momentum total = m
₁v_1o + m₂v_2o

Final momentum total = m₁v_1f
+ m₂v_2f

Conservation of momentum occurs when the initial momentum total equals the final momentum total.

Conservation of momentum equation:

Procedure:

1. Determine a hypothesis for the given collisions by answering the following question: Which collisions
   will experience conservation of momentum?
2. Use the following simulation, Collision Lab, to complete this lab. Note: The simulation will open in a
   new window and requires Java to run.
   
   
   

   Select to Run

   © 2015 University of Colorado

3. In the simulation, ensure that you are using the “Introduction” tab and for the table,
   select “More Data” so that you can see the velocity of each mass. Also, move the slider
   for “Sim Speed” so that it is all the way to the left. This makes the simulation slow enough to
   see what happens. For the table on the right, you can choose to have “Velocity Vectors”
   and “Show Values” boxes checked if you please.
4. You will use the table at the bottom of the simulation to input values of mass and initial velocity for
   the two masses. For tables 1 through 6, you will record the velocity directly after the masses collide.
   This will be the final velocity for each mass. Make sure that the two masses are at least 2 m apart by
   changing their position values. Remember to hit the reset button to start the next collision.
5. In Collision 1 and Collision 2, ensure “Elasticity” is 100%
   by moving the slider all the way to the right. This signifies an “Elastic” collision. Watch
   the simulation closely and make note of what an elastic collisions looks like.
   Record the final
   velocity and complete the calculations for each trial.
6. In Collision 3 and Collision 4, change “Elasticity” to 0%
   by moving the slider all the way to the left. This signifies an “Inelastic” collision. Again,
   watch the simulations closely and make note of what an inelastic collision looks like.
   Record the final
   velocity and complete the calculations for each trial.
7. For Collision 5 and Collision 6, you are going to create your own data.
   Choose your own masses and initial velocities for the two masses. You can choose a rear-end collision or a
   head-on collision. One must be elastic and the other must be inelastic.
   Record and complete the
   calculations for each trial.
8. After completing collisions 1 through 6,
   complete the last
   table by calculating the initial momentum total and final momentum total for each collision.

9. Input Values

   ---

   Elastic Collision
   between equal mass:

   Collision 1	Mass (kg)	Initial Velocity (m/s)	Final Velocity (m/s)	Momentum Initial (kg*m/s)	Momentum Final (kg*m/s)
   Mass 1	2.0	+ 50.0
   Mass 2	2.0	– 50.0

   ---

   Elastic Collision
   between unequal mass:

   Collision 2	Mass (kg)	Initial Velocity (m/s)	Final Velocity (m/s)	Momentum Initial (kg*m/s)	Momentum Final (kg*m/s)
   Mass 1	1.0	+ 50.0
   Mass 2	2.0	– 50.0

   ---

   Inelastic Collision
   between equal mass:

   Collision 3	Mass (kg)	Initial Velocity (m/s)	Final Velocity (m/s)	Momentum Initial (kg*m/s)	Momentum Final (kg*m/s)
   Mass 1	2.0	+ 50.0
   Mass 2	2.0	– 50.0

   ---

   Inelastic Collision
   between unequal mass:

   Collision 4	Mass (kg)	Initial Velocity (m/s)	Final Velocity (m/s)	Momentum Initial (kg*m/s)	Momentum Final (kg*m/s)
   Mass 1	1.0	+ 50.0
   Mass 2	2.0	– 50.0

   ---

   Your own Elastic Collision:

   Collision 5	Mass (kg)	Initial Velocity (m/s)	Final Velocity (m/s)	Momentum Initial (kg*m/s)	Momentum Final (kg*m/s)
   Mass 1
   Mass 2

   ---

   Your own Inelastic Collision:

   Collision 6	Mass (kg)	Initial Velocity (m/s)	Final Velocity (m/s)	Momentum Initial (kg*m/s)	Momentum Final (kg*m/s)
   Mass 1
   Mass 2

   ---

   Calculations:

   Collision	Total Momentum Initial (kg*m/s)	Total Momentum Final (kg*m/s)
   Collision 1
   Collision 2
   Collision 3
   Collision 4
   Collision 5
   Collision 6

   ---

   Questions and Conclusion:

10. Based on your observations
    of the six collisions, describe the physical difference
    between elastic and inelastic collisions.
11. How are you able to
    determine if conservation of momentum occurs in each
    collision?
12. Write a complete conclusion
    for this lab.

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