FREE ESSAY ON MOMENTUM

MOMENTUM

Conservation of Momentum
Kristin Favreau October 26, 1999
Purpose: To show that momentum is conserved in a closed system by illustrating the
conservation of momentum in an elastic collision and an inelastic collision. 
Method: If momentum is conserved in a closed system, the total momentum of the system
before collision should equal the total momentum of the system after the collision.
Strobe photos will be used in the calculations that will prove that momentum is
conserved.
1.) Elastic collision: A strobe photo will be used that shows a large glider smashing
into a smaller glider which is initially at rest. This will cause the smaller glider to
move and the large glider will continue to move also. 
2.) Inelastic collision: A strobe photo will be used that shows a glider smashing into
another glider which is initially at rest. When they collide the two gliders will stick
together and will move.
-The masses, distances and times will be measured in order to calculate the momentums of
the systems before and after collision occurs. 
Data: 
V = d/t P = m x v
1.) Elastic collision: 
When Mass Distance Time Velocity Momentum
Glider A Before Collision .31215 kg .009m .6s .015 m/s .00468 Kg m/s
Glider B Before Collision .15580 kg - - 0 m/s 0 Kg m/s
Glider A After Collision .31215 kg .005m 1.0s .005 m/s .00156 Kg m/s
Glider B After Collision .15580 kg .011m .6s .018 m/s .00280 Kg m/s
2.) Inelastic collision:
When Mass Distance Time Velocity Momentum
Glider C Before Collision .3105 kg .016m 1.0s .016 m/s .004968 Kg m/s
Glider D Before Collision .3000 kg - - 0 m/s 0 Kg m/s
Gliders C+D After Collision .6105 kg .015m 2.0s .008 m/s .004884 Kg m/s
Calculations:
1.) Elastic collision:
Before After 
Glider A .00468 Kg m/s .00156 Kg m/s
Glider B + 0 Kg m/s +.00280 Kg m/s
.00468 Kg m/s .00436 Kg m/s
2.) Inelastic collision: 
Total momentum before = Total momentum after
mv + mv = (m + m ) v 
(.3105kg x .016 m/s) + 0 = (.3105 kg + .3000 kg) x .008 m/s
.0050 Kg m/s = .0049 Kg m/s
Conclusion: Through experiments with strobe photos involving elastic and inelastic
collisions, I was able to show that momentum is contained within a closed system. My
efficiency for the elastic collision was 3.54% and my efficiency for the inelastic
collision was 1.01 %. Less than 10 % of the momentum was lost in either collision
indicating a good experiment. The lost momentum can be attributed to the transfer from
mechanical energy to thermal energy.
Sources of Error:
1.) The distances measured in the two strobe photos were estimated.
2.) The measurement of time was an average.
% error = difference x 100 
sum of all
1.) % error = .00032 x 100 = 3.54 % error
.00904 
2.) % error = .0001 x 100 = 1.01 % error
.0099