Name: ______________________________
Virtual Momentum Lab
OBJECTIVE:
Pd: ___
To investigate elastic and inelastic collisions
AIR TRACK SIMULATION:
This simulation models a basic air track with two blocks.
http://www.physicslessons.com/exp5b.htm
Adapted from G.DeCecco and http://physicsquest.homestead.com
GENERAL DIRECTIONS:
A.
B.
C.
D.
E.
F.
Drag the RED Block to the '0' mark on the ruler & drag the GREEN Block to the '3' mark for all experiments
Click GO to start Simulations
STOP the simulation after the blocks reach the end of ruler
Read FINAL VELOCITIES by clicking on the GREEN TAB of the Momentum Values (box on right)
Set e at '1' for ELASTIC COLLISIONS
Set e at '0' for INELASTIC COLLISIONS
A. ELASTIC COLLISIONS – QUALITATIVE ANALYSIS:
FOR EACH CASE:
1. Set the values & click on GO
2. Observe what happens AFTER the collision
3. Answer the questions indicating your observations regarding the velocities for each mass (how fast, how
slow, direction)
m 1 = m2
m1 = 2 kg m 2 = 2 kg
v1 = 5 m/sec v 2 = 0 m/sec
Case I -- Elastic Collision
What happens to Mass 1 (RED)?
_________________________________________________________________
What happens to Mass 2 (GREEN)?
_________________________________________________________________
Case II -- Elastic Collision
m1 > m2
m1 = 2 kg m 2 = 1 kg
v1 = 5 m/sec v 2 = 0 m/sec
What happens to Mass 1 (RED)?
_________________________________________________________________
What happens to Mass 2 (GREEN)?
Case III -- Elastic Collision
m1 < m2
m1 = 1 kg m 2 = 2 kg
v1 = 5 m/sec v 2 = 0 m/sec
What happens to Mass 1 (RED)?
_________________________________________________________________
What happens to Mass 2 (GREEN)?
B. ELASTIC COLLISIONS – QUANTITATIVE ANALYSIS:
FOR EACH CASE:
1. Set “e” at 1
2. Find the values for the FINAL VELOCITIES (v 1' and v 2') of each block
3. Record the values on the tables
4. Perform your OWN calculations for MOMENTUM and KINETIC ENERGY (showing your work)
Elastic Case I
RED BLOCK
m1 = 3 kg
v1 = 5 m/s
Initial Momentum =
GREEN BLOCK
m2 = 2 kg
v2 = 0 m/s
Initial Momentum =
Initial KE =
Initial KE =
v1’=
v2’=
Final Momentum =
Final Momentum =
Final KE =
Final KE =
Was momentum conserved? ____________
Was KE conserved? ______________
Elastic Case II
RED BLOCK
m1 = 3 kg
v1 = 5 m/s
Initial Momentum =
GREEN BLOCK
m2 = 2 kg
v2 = -4 m/s
Initial Momentum =
Initial KE =
Initial KE =
v1’=
v2’=
Final Momentum =
Final Momentum =
Final KE =
Final KE =
Was momentum conserved? ____________
Was KE conserved? ______________
Elastic Case III
RED BLOCK
m1 = 3 kg
v1 = 5 m/s
Initial Momentum =
GREEN BLOCK
m2 = 2 kg
v2 = 1 m/s
Initial Momentum =
Initial KE =
Initial KE =
v1’=
v2’=
Final Momentum =
Final Momentum =
Final KE =
Final KE =
Was momentum conserved?____________
Was KE conserved?______________
Elastic Case IV
RED BLOCK
m1 = 3 kg
v1 = 5 m/s
Initial Momentum =
GREEN BLOCK
m2 = 3 kg
v2 = - 5 m/s
Initial Momentum =
Initial KE =
Initial KE =
v1’=
v2’=
Final Momentum =
Final Momentum =
Final KE =
Final KE =
Was momentum conserved?____________
Was KE conserved?______________
C. INELASTIC COLLISIONS – QUANTITATIVE ANALYSIS:
FOR EACH CASE:
1. Set “e” at 0
2. Find the values for the FINAL VELOCITIES (v 12' and v 2') of each block
3. Record the values on the tables
4. Perform your OWN calculations for MOMENTUM and KINETIC ENERGY (showing your work)
Inelastic Case I
RED BLOCK
m1 = 3 kg
v1 = 5 m/s
Initial Momentum =
GREEN BLOCK
m2 = 2 kg
v2 = 0 m/s
Initial Momentum =
Initial KE =
Initial KE =
v1’=
v2’=
Final Momentum =
Final Momentum =
Final KE =
Final KE =
Was momentum conserved? ____________
Was KE conserved? ______________
Inelastic Case II
RED BLOCK
m1 = 3 kg
v1 = 5 m/s
Initial Momentum =
GREEN BLOCK
m2 = 2 kg
v2 = -4 m/s
Initial Momentum =
Initial KE =
Initial KE =
v1’=
v2’=
Final Momentum =
Final Momentum =
Final KE =
Final KE =
Was momentum conserved? ____________
Was KE conserved ?______________
Inelastic Case III
RED BLOCK
m1 = 3 kg
v1 = 5 m/s
Initial Momentum =
GREEN BLOCK
m2 = 2 kg
v2 = 1 m/s
Initial Momentum =
Initial KE =
Initial KE =
v1’=
v2’=
Final Momentum =
Final Momentum =
Final KE =
Final KE =
Was momentum conserved? ____________
Was KE conserved?______________
Inelastic Case IV
RED BLOCK
m1 = 3 kg
v1 = 5 m/s
Initial Momentum =
GREEN BLOCK
m2 = 3 kg
v2 = -5 m/s
Initial Momentum =
Initial KE =
Initial KE =
v1’=
v2’=
Final Momentum =
Final Momentum =
Final KE =
Final KE =
Was momentum conserved?____________
Was KE conserved?______________
DISCUSSION QUESTIONS:
1. What are the two major types of collisions and explain each one so it is clear that you understand
what makes them different.
2. How did this online simulation help with your understanding of momentum in collisions?
3. Thinking about momentum, circle all of the following statements that are true.
a. Momentum is a vector quantity.
b. The standard unit on momentum is the Joule.
c. An object with mass will have momentum.
d. An object which is moving at a constant speed has momentum.
e. An object can be traveling eastward and slowing down; its momentum is westward.
f. The momentum of an object varies directly with the speed of the object.
g. Two objects of different mass are moving at the same speed; the more massive object will
have the greatest momentum.
h. A less massive object can never have more momentum than a more massive object.
i. An object with a changing speed will have a changing momentum.
4. Circle the statements that are true about elastic and inelastic collisions.
a. Perfectly elastic and perfectly inelastic collisions are the two opposite extremes when two
objects collide.
b. Most collisions in real life tend to be partially to completely elastic.
c. Momentum is conserved in an elastic collision but not in an inelastic collision.
d. The kinetic energy of an object remains constant during an elastic collision.
e. Most collisions are not inelastic because the collision forces cause energy of motion to be
transformed into sound, light and thermal energy (to name a few).
f. A moving air track glider collides with a second stationary glider of identical mass. The first
glider loses all of its kinetic energy during the collision as the second glider is set in motion
with the same original speed as the first glider. Since the first glider lost all of its kinetic
energy, this is a perfectly inelastic collision.
g. The collision between a tennis ball and a tennis racket tends to be more elastic in nature than a
collision between a halfback and linebacker in football.
5. A truck driving along a highway road has a large quantity of momentum. If it moves at the same
speed but has twice as much mass, its momentum is ________________.
a. zero
b. quadrupled
c. doubled
d. unchanged
6. The firing of a bullet by a rifle causes the rifle to recoil backwards. The speed of the rifle's recoil is
smaller than the bullet's forward speed because the ___.
a. force against the rifle is relatively small
c. rifle has lots of mass
e. none of these
b. speed is mainly concentrated in the bullet
d. momentum of the rifle is unchanged