# Conceptual_Physics_Lab_08_Momentum_and_Collisions__Explore_Learning_

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```					CONCEPTUAL PHYSICS                                       Mr. O’Donnell PHHS Room 141

Names ___________________________________________________ Date __________

Lab #8

Title:           Momentum and Collisions

Purpose:         To measure momentum and kinetic energy before and after various types
of collisions using an air track simulation.

Website:         Go to Mr. O’Donnell’s Schoolwires Web Page and open the link to
Explore Learning. Log on and open the Air Track gizmo.

Using the gizmo, perform the following simulated collisions between the
Red and Blue gliders on the air track

Elastic Collisions

1. For elastic collisions set the Elasticity at 1.0.
2. Check the boxes to show glider data.
3. Enter mass values (between 0.2 and 3.0) and initial velocities (between -10m/s
and 10m/s) for each glider and record in the Data Table below. Note: to make the
Blue car move to the left enter a negative initial velocity (e.g., -10.0)
4. Hit Play on the applet and allow the cars to collide.
5. After they collide, hit Pause.
6. Record the velocit for the Red and Blue car as the Final Velocity for each car in
the Data Table below.
7. Repeat the simulation three more times, changing the mass and initial velocity for
each car in each new trial. (Each trial must have different values for each
variable).
8. Record Final velocities for each trial in the Data Table below.

Elastic Collision Data Table
Red Car                             Blue Car
Mass       Initial     Final       Mass        Initial     Final
m1       velocity    velocity      m2        velocity    velocity
Trial
(kg)         V1i        V1f        (kg)          V2i        V2f
(m/s)      (m/s)                    (m/s)      (m/s)
1
2
3
4

1
CONCEPTUAL PHYSICS                                         Mr. O’Donnell PHHS Room 141

Inelastic Collisions

1. For inelastic collisions set the Elasticity at 0.0.
2. Perform the simulation for four different combinations of mass and initial velocity
as done for the elastic collisions (you may use the same mass and velocity inputs
as used for the elastic collisions).
3. Record all data for each trial in the Data Table below.

Inelastic Collision Data Table
Red Glider                            Blue Glider
Mass        Initial      Final       Mass        Initial      Final
m1        velocity     velocity      m2        velocity     velocity
Trial
(kg)          V1i         V1f        (kg)          V2i         V2f
(m/s)       (m/s)                    (m/s)       (m/s)
1
2
3
4

Calculations: For each trial calculate the momentum of each car before and after the
collision by multiplying mass and velocity (show sample calculations in
for one trial in your lab report):

p=mv

Then calculate total momentum of both gliders together before and after
the collision using the following formulas:
pTi = m1v1i + m2v2i
pTf = m1v1f + m2v2f

Note: For perfectly inelastic collisions:
pTf = (m1 + m2) vf

For ease of calculation, it is suggested you copy the data tables above and the calculations
tables below into Excel. Then enter the formulas into the appropriate cells to perform the
required calculations referencing the correct data table cells as input to the formulas.

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CONCEPTUAL PHYSICS                                      Mr. O’Donnell PHHS Room 141

Calculated Momentum (kg m/s)
Red Glder           BlueGlider                          Total
Trial      Before       After       Before        After       Before           After
P1i          P1f         P2i           P2f         PTi              PTf
Elastic
1
2
3
4
Inelastic
1
2
3
4

1. Is momentum the same for each car before and after each collision? If
not, what factor determines whether a car gains or loses momentum
after a collision?

2. Is total momentum the same before and after each collision? What law
is illustrated by the results?

3. Look at the kinetic energy before and after an ielastic and an inelastic
collision. In which type of collision is total kinetic energy the same
before and after the collision?

4. Is it possible for total momentum to be negative? If so, how? If not,
why not?

5. Answer the assessment questions at the end of the gizmo.

3

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