MEGA-MENTUM LAB
http://phet.colorado.edu/sims/collision-lab/collision-lab_en.html
Momentum and Simple 1D Collisions PhET Lab
Introduction: When objects move, they have momentum. Momentum, p, is simply the product of
an object’s mass (kg) and its velocity (m/s). The unit
for momentum, p, is kgm/s. During a collision, an object’s momentum can be transferred to impulse,
which is the product of force (N) and time (s) over which the force acts. This allows us to write the
momentum-impulse theorem:
Procedure: Play with the Sims  Physics Motion  Collision Lab
Work with 1D collisions at this level. Later (AP Physics) you'll use
solve 2D collisions. Velocity to the right is positive, left is negative.
in the simulation after you have completed the tables.




Important Formulas: m1v1  m2 v2  ptotal  m1v1  m2 v2
p  mv  Ft
A) Perfectly Elastic Collisions:
+
B) To begin a collision: To restart a collision:



trigonometry to
Check your work
+
Take some time to familiarize yourself with the sim and perfect collisions. Play.
Investigate. Learn.
What defines a collision as being
elastic?___________________________________________
Two objects with the same mass move toward each other with the same speed
and experience an elastic collision. Compare the final velocities of each object
their initial velocities.
to

A less-massive moving object has an elastic collision with a more-massive object that is not
moving. Compare the initial velocity (speed and direction) of the less-massive object to its
final velocity

Simulate the four elastic collisions below. Complete the table using math formulas and the simulation.

o Investigate the action of a more-massive moving object striking a less-massive target object.
o Investigate the action of a less-massive moving object striking a more-massive target object.
Complete the below table without the simulation and check your work in the simulation
BEFORE COLLISION
#
1
m1
2.0 kg
m2
2.0 kg
2
2.5 kg
5.0 kg
KE stands for Kinetic Energy
v1
1.5 m/s
v2
AFTER COLLISION
Record From Computer
v1
v2
0 kg·m/s
-1.0 m/s
KE  1 mv2
2
ptotal
0 kg·m/s
and is measured in joules. Note that kinetic energy is not a vector
quantity. Describe the effect of an elastic collision on the total kinetic energy of the two-object system.
_______________________________________________________________________________________
B) Perfectly Inelastic Collisions: Select:


m1v1  m2 v2
v'12 
m1  m2



+
+
m1v1before + m2 v2before =
m1 + m2  vafter
Complete the below table without the simulation an
d check your work in the simulation.
BEFORE COLLISION
#
1
m1
2.0 kg
m2
2.0 kg
v1
1.5 m/s
v2
0
2
3.0 kg
6.0 kg
1.5 m/s
-0.75 m/s
AFTER COLLISION
ptotal
Calculate v’ Before Computer
C) Perfectly Inelastic 2DCollisions: Select:Advanced +
+
You will have to move the starting points around so they collide 
BEFORE COLLISION
AFTER
COLLISION
ptotal
Record From Computer
Calculate p’ Before
Computer
ptotal
#
m1
m2
V2x
V1y
1
2.0 kg
2.0 kg
1.5 m/s
1.7 m/s
/
/
/
/
2
3.0 kg
6.0 kg
1.5 m/s
0.5 m/s
/
/
/
/
v1x /v1y /v2x /v2y