Conservation of Momentum Lab
In this lab you will be using two balls with virtual lab software to simulate the two carts lab last week.
This time you will be measuring actual velocities, not just estimating and observing the changes in
velocities after “collisions.” So please in your conclusion compare your results in last week’s lab (with
the carts) with this one. Each part below corresponds to the same section in last week’s lab. You
should have one general procedure at the beginning (brief, in your own words) as well as one or more
tables of the results. (Consider the example in the ½-page handout given to you.) You will
demonstrate that momentum is conserved in each part below, as well as demonstrating the
conservation of kinetic energy in section H below only.
A
ELASTIC collision: Set the values of the red ball and the blue ball to be the same (5kg). Set
the initial velocity of the red ball to be “0,” and that of the blue ball to be 6 m/s. Now click on
“play” and observe what happens. Compare the results in your lab book (create a table) with
what you observed last week with the two carts. Using conservation of momentum,
calculate the momentum before and after the collision. Show that it is conserved.
B
INELASTIC collision: Set the “coefficient of restitution” to 0 (making it a completely inelastic
collision). Again set the initial velocity of the red ball to be 0 and that of the blue ball to be 6
m/s. Now click on “play” and observe what happens. Compare the results in your lab book
(create a table) with what you observed last week with the two carts. Using conservation of
momentum, calculate the momentum before and after the collision. Show that it is
conserved.
C
ELASTIC collision: Re-set the “coefficient of restitution” to 1 (making it a completely elastic
collision). This time set the initial velocity of the red ball to be -6.0 and that of the blue ball to
be 6 m/s. Now click on “play” and observe what happens. Compare the results in your lab
book (create a table) with what you observed last week with the two carts. Using
conservation of momentum, calculate the momentum before and after the collision.
Show that it is conserved.
D
INELASTIC collision: Set the “coefficient of restitution” to 0 (making it a completely inelastic
collision). Keep the velocities of the two balls at 6.0 and -6.0 m/s. Click on “play” and observe
what happens. Compare the results in your lab book (create a table) with what you observed
last week with the two carts. Using conservation of momentum, calculate the momentum
before and after the collision. Show that it is conserved.
E
ELASTIC collision: Re-set the “coefficient of restitution” to 1 (making it a completely elastic
collision). This time set the initial velocity of the red ball to be -6.0 and that of the blue ball to
be 3.0 m/s. Now click on “play” and observe what happens. Compare the results in your lab
book (create a table) with what you observed last week with the two carts. Using
conservation of momentum, calculate the momentum before and after the collision.
Show that it is conserved. What happened to the two velocities?
F
INELASTIC collision: Set the “coefficient of restitution” to 0 (making it a completely inelastic
collision). Keep the velocities of the two balls at -6.0 and 3.0 m/s. Click on “play” and observe
what happens. Compare the results in your lab book (create a table) with what you observed
last week with the two carts. Using conservation of momentum, calculate the momentum
before and after the collision. Show that it is conserved.
G
ELASTIC collision: Re-set the “coefficient of restitution” to 1 (making it a completely elastic
collision). Set the mass of the red ball to be 10 kg. The red ball will now have double the
mass of the blue ball. Set the velocity of the red ball to be 0 and that of the blue ball at 6.0
m/s. Click on “play” and observe what happens. Compare the results in your lab book (create
a table) with what you observed last week with the two carts. Using conservation of
momentum, calculate the momentum before and after the collision. Show that it is
conserved.
H
ELASTIC collision: Set the mass of the red ball to be 9 kg, and that of the blue ball to be 3.0
kg. The red ball will now have triple the mass of the blue ball. Set the velocity of the red ball
to be 0 and that of the blue ball at 6.0 m/s. Click on “play” and observe what happens.
Compare the results in your lab book (create a table) with what you observed last week with
the two carts. Using conservation of momentum, calculate the momentum before and
after the collision. Show that it is conserved. Also calculate the kinetic energy before
and after the collision and show that it is conserved also in purely elastic collisions.
J
ELASTIC collision: Set the mass of the red ball to be 10 kg, and that of the blue ball to be 5
kg. The red ball will now have double the mass of the blue ball. This time set the initial
velocity of the red ball to be -6.0 and that of the blue ball to be 0. Now click on “play” and
observe what happens. Compare the results in your lab book (create a table) with what you
observed last week with the two carts. Using conservation of momentum, calculate the
momentum before and after the collision. Show that it is conserved. What happened to
the two velocities?
K
ELASTIC collision: Set the mass of the red ball to be 9 kg, and that of the blue ball to be 3.0
kg. The red ball will now have triple the mass of the blue ball. The velocities remain the same.
Now click on “play” and observe what happens. Compare the results in your lab book (create
a table) with what you observed last week with the two carts. Using conservation of
momentum, calculate the momentum before and after the collision. Show that it is
conserved. What happened to the two velocities?