Physics lab report 8 PDF

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Collisions in One Dimension Akshay Muralisrinivasan Partner: Pierre I. Section 007 Date Performed: 11/6/117 Date Due: 11/13/17

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Objective: To see whether momentum and kinetic energy are conserved in elastic and inelastic collisions in one dimension.

Description: One glider was on an air track and another glider with the same, smaller, or larger mass collided with it. Two photogates were positioned so that the velocities of the gliders could be measured before and after colliding with one another by detecting a note card attached to the top of each glider. Data was collected and recorded for this.

Theory: The main theory being tested for this experiment was the conservation of momentum. We can use Newton’s second law of motion of force = mass * acceleration and integrate it to get momentum. Also, the law of conservation of energy is being observed in this as the initial potential energy + initial kinetic energy should equal final potential energy + final kinetic energy of an object. For elastic collisions, kinetic energy should be conserved but not for inelastic collisions.

Procedure: Before any data was taken, the air track needed to be calibrated. Two photogates were attached to the computer and were used to measure the velocities of the colliding gliders. The note cards attached to the gliders were measured in order to be consistent. For the first scenario, the gliders that had the closest masses collided with one another and data was taken. This scenario was repeated but the second time around, pieces were furnished to the colliding ends of the gliders so that they would stick when they collided. The first part was to measure about the elastic collisions and the second part dealt with inelastic collisions.

Data and Calculations: Part 1:

M1=M2 M1=M2 M1=M2 M1M2

v1

v2

v1’

v2’

v1’t

v2’t

.25 .78 .62 1.19 1.39 .72 .56 .38 .37

0 0 0 0 0 0 0 0 0

0 0 0 -.31 -.36 -.17 +.31 +.21 +.22

+.21 +.68 +.54 +.71 +.83 +.46 +1.19 +.83 +.82

0 0 0 -.34 -.34 -.34 +.34 +.34 +.34

1 1 1 +.66 +.66 +.66 +1.34 +1.34 +1.34

Total energy before collision .005 J .046 J .029 J .106 J .114 J .09 J .02 J .01 J .01 J

Total energy after collision .0033 J .035 J .022 J .84 J .114 J .034 J .1206 J .058 J .057 J

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M1=M2 M1=M2 M1=M2 M1M2

v1

v2

v1’

v2’

v1’t

v2’t

.65 .45 .36 .91 1.08 1.06 .78 .51 1.03

0 0 0 0 0 0 0 0 0

+.37 +.26 +.23 +.43 +.45 +.32 +.54 +.37 +.60

+.37 +.26 +.23 +.43 +.45 +.32 +.54 +.37 +.60

.33 .23 .18 .30 .36 .35 .52 .34 .69

.33 .23 .18 .30 .36 .35 .52 .34 .69

Total energy before collision .03 J .02 J .01 J .06 J .09 J .08 J .05 J .02 J .08 J

Total energy after collision .02 J .01 J .008 J .042 J .046 J .023 J .066 J .031 J .081 J

Error Analysis: Much error in this experiment was due to human error due to the fact that we could have pushed the gliders with different forces. This could have affected how each glider collided and therefore could have affected the measurements taken. In addition, friction could have led to the loss of kinetic energy which was a major source of error in our experiment. Calibration of both the photogates and the air track could have also deviated values as calibration may not have been done properly.

Conclusion: Why can momentum be conserved when energy is not? -

In an inelastic collision, the momentum is still conserved but the energy is not in this case.

How well is energy conserved? -

Energy was not conserved very well.

How does your results differ from theory? -

Kinetic energy was not conserved when it was supposed to be.

Do you expect a bit of KE lost during the collision? -

Yes, it is expected that some Kinetic Energy would be lost.

What is occurring during the collision? -

In this collision, both momentum and energy should be conserved.

Explain in the case of spring bumpers. If you have disk magnets how would they influence the experiment? Explain. -

No because the bumpers on the gliders acted as springs. When they collided, kinetic energy was turned into potential energy so some kinetic energy is lost. The magnets

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would cause the bumpers to have minimal collision since they repel each other. This would reduce the effect of friction therefore having less effect on reducing the kinetic energy. What is occurring to the energy? How does the energy get dissipated? -

The energy is not conserved and is lost due to the inelastic collision.

When the gliders collide do you hear a sound? -

Yes, you can hear a sound.

Could this contribute to the energy and momentum balance in your experiments? -

Yes, the gliders come into contact with one another the kinetic energy can be converted into sound waves which reduce the kinetic energy.

How does this compare with the kinetic energy of your gliders? -

Since the kinetic energy lost to sound waves is much smaller than that lost to something like friction, the energy lost to sound is negligible....