# collision

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```					GateWay CC

PHY101 Physics Lab:                                            ELASTIC COLLISION
Purpose

The purpose of this lab is to calculate the initial/final velocity of objects in elastic collision,
using the principle of conservation of momentum and conservation of energy during the
collision
Theory

Measurement of velocity in this lab is based on the principle of conservation of
momentum and conservation of energy. If m is the mass of the first
object and M is the mass of the second object in elastic collision,
then based on the principle of conservation of momentum:

Momentum before the collision = Momentum after the collision

m  v1i  M  v2i  (m  M )  v f

where:
v1i - is the initial velocity of the of the first object.
V2i - is the initial velocity of the of the second object.

vf - is the final velocity of two objects joined after the collision.
m  v1i  M  v 2i - is momentum of the system before the collision.
( m  M )  v f - is momentum of the system after the collision.

If we solve last equation for final velocity of two objects after the collision:

m  v1i  M  v2i
vf 
mM

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GateWay CC

INITIAL SETUP

a) Go to the following website and follow instructions bellow.
http://www.gwc.maricopa.edu/class/phy101/Flash/collision.htm

Description of the simulation: This flash animation simulates collisions in one dimension. To run
simulations enter the masses of RED and BLUE objects and their initial velocities (velocities
before the collision). Press "Go" to initiate the simulation. Press "Stop" at any time to pause the
simulation. Pressing "Go" will restart it at that point. By entering various data for the masses
and initial velocities of each object you can simulate your own collision.

Case 1: Elastic collision between two object of Equal Mass

Settings: Blue object is at REST before the collision.
Red Object         Red Object        Blue Object     Blue Object
Mass (mr)         Velocity(mv)        Mass(mb)       Velocity(mb)
kg                m/s                kg              m/s
1.0                +1                 1.0             0.0
Record these values of your notebook – report. Before running the simulation calculate the
following initial values and record them in table on your notebook.
Initial Momentum of           Initial Momentum of           Total Initial
Red Object                   Blue Object              Momentum
mr*vr                        mb*vb                mr*vr + mb*vb
kgm/s                         kgm/s                   kgm/s

Press "GO" and watch the simulated collision. Press "STOP" before the blue or red object strikes
the right or left side bumper. Computer will display final velocities of two objects – velocities
after the collision. Record these velocities on your notebook.
Velocity of Red Object          Velocity of Blue Object
m/s                              m/s

Indicate each object direction with a + or - sign. Plus sign indicate motion to the RIGHT, minus

Reset the Experiment.

Calculate the following final values after the collision:
Final Momentum of              Final Momentum of            Total Final
Red Object                     Blue Object              Momentum
mr*vr                          mb*vb                mr*vr + mb*vb
kgm/s                          kgm/s                   kgm/s

What is the relationship between the initial and final momentums?

Describe the motion of the red and blue cart before and after the collision?

Where was the point of impact? _________ cm

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GateWay CC

Case 2: Elastic collision between two object of Different Mass

Settings: Blue object is at REST before the collision.
Red Object           Red Object       Blue Object     Blue Object
Mass (mr)           Velocity(mv)       Mass(mb)       Velocity(mb)
kg                  m/s               kg              m/s
1.0                  +1                3.0             0.0
Record these values of your notebook – report. Before running the simulation calculate the
following initial values and record them in table on your notebook.
Initial Momentum of           Initial Momentum of            Total Initial
Red Object                   Blue Object               Momentum
mr*vr                        mb*vb                 mr*vr + mb*vb
kgm/s                         kgm/s                    kgm/s

Press "GO" and watch the simulated collision. Press "STOP" before the blue or red object strikes
the right or left side bumper. Computer will display final velocities of two objects – velocities
after the collision. Record these velocities on your notebook.
Velocity of Red Object          Velocity of Blue Object
m/s                              m/s

Indicate each object direction with a + or - sign. Plus sign indicate motion to the RIGHT, minus

Reset the Experiment.

Calculate the following final values after the collision:
Final Momentum of              Final Momentum of             Total Final
Red Object                     Blue Object               Momentum
mr*vr                          mb*vb                 mr*vr + mb*vb
kgm/s                          kgm/s                    kgm/s

What is the relationship between the initial and final momentums?

Describe the motion of the red and blue cart before and after the collision?

Where was the point of impact? _________ cm

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GateWay CC

Case 3: Elastic collision between two objects in motion and Equal Mass

Settings: Objects are traveling in opposite direction.
Red Object           Red Object       Blue Object     Blue Object
Mass (mr)           Velocity(mv)       Mass(mb)       Velocity(mb)
kg                  m/s               kg              m/s
1.0                  +1                1.0             -1.0
Record these values of your notebook – report. Before running the simulation calculate the
following initial values and record them in table on your notebook.
Initial Momentum of           Initial Momentum of            Total Initial
Red Object                   Blue Object               Momentum
mr*vr                        mb*vb                 mr*vr + mb*vb
kgm/s                         kgm/s                    kgm/s

Press "GO" and watch the simulated collision. Press "STOP" before the blue or red object strikes
the right or left side bumper. Computer will display final velocities of two objects – velocities
after the collision. Record these velocities on your notebook.
Velocity of Red Object          Velocity of Blue Object
m/s                              m/s

Indicate each object direction with a + or - sign. Plus sign indicate motion to the RIGHT, minus

Reset the Experiment.

Calculate the following final values after the collision:
Final Momentum of              Final Momentum of             Total Final
Red Object                     Blue Object               Momentum
mr*vr                          mb*vb                 mr*vr + mb*vb
kgm/s                          kgm/s                    kgm/s

What is the relationship between the initial and final momentums?

Describe the motion of the red and blue cart before and after the collision?

Where was the point of impact? _________ cm

Gatewaycc: 9265c0db-5e2f-4098-9e7d-6b5f1cbefe46.doc   Page 4                           Last Updated: 4/3/2010
GateWay CC

Case 4: Elastic collision between two objects in motion and Different Mass

Settings: Objects are traveling in opposite direction.
Red Object           Red Object       Blue Object     Blue Object
Mass (mr)           Velocity(mv)       Mass(mb)       Velocity(mb)
kg                  m/s               kg              m/s
1.0                  +1                3.0             -1.0
Record these values of your notebook – report. Before running the simulation calculate the
following initial values and record them in table on your notebook.
Initial Momentum of           Initial Momentum of            Total Initial
Red Object                   Blue Object               Momentum
mr*vr                        mb*vb                 mr*vr + mb*vb
kgm/s                         kgm/s                    kgm/s

Press "GO" and watch the simulated collision. Press "STOP" before the blue or red object strikes
the right or left side bumper. Computer will display final velocities of two objects – velocities
after the collision. Record these velocities on your notebook.
Velocity of Red Object          Velocity of Blue Object
m/s                              m/s

Indicate each object direction with a + or - sign. Plus sign indicate motion to the RIGHT, minus

Reset the Experiment.

Calculate the following final values after the collision:
Final Momentum of              Final Momentum of             Total Final
Red Object                     Blue Object               Momentum
mr*vr                          mb*vb                 mr*vr + mb*vb
kgm/s                          kgm/s                    kgm/s

What is the relationship between the initial and final momentums?

Describe the motion of the red and blue cart before and after the collision?

Where was the point of impact? _________ cm

Gatewaycc: 9265c0db-5e2f-4098-9e7d-6b5f1cbefe46.doc   Page 5                           Last Updated: 4/3/2010
GateWay CC

Case 5: Elastic collision between two objects in motion and Different Mass and Different Speed

Settings: Blue object is at REST before the collision.
Red Object           Red Object       Blue Object     Blue Object
Mass (mr)           Velocity(mv)       Mass(mb)       Velocity(mb)
kg                  m/s               kg              m/s
3.0                  +1                1.0             -3.0
Record these values of your notebook – report. Before running the simulation calculate the
following initial values and record them in table on your notebook.
Initial Momentum of           Initial Momentum of            Total Initial
Red Object                   Blue Object               Momentum
mr*vr                        mb*vb                 mr*vr + mb*vb
kgm/s                         kgm/s                    kgm/s

Press "GO" and watch the simulated collision. Press "STOP" before the blue or red object strikes
the right or left side bumper. Computer will display final velocities of two objects – velocities
after the collision. Record these velocities on your notebook.
Velocity of Red Object          Velocity of Blue Object
m/s                              m/s

Indicate each object direction with a + or - sign. Plus sign indicate motion to the RIGHT, minus

Reset the Experiment.

Calculate the following final values after the collision:
Final Momentum of              Final Momentum of             Total Final
Red Object                     Blue Object               Momentum
mr*vr                          mb*vb                 mr*vr + mb*vb
kgm/s                          kgm/s                    kgm/s

What is the relationship between the initial and final momentums?

Describe the motion of the red and blue cart before and after the collision?

Where was the point of impact? _________ cm

Gatewaycc: 9265c0db-5e2f-4098-9e7d-6b5f1cbefe46.doc   Page 6                           Last Updated: 4/3/2010

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