Linear Momentum

Topics: Momentum, Velocity, Mass Pages: 5 (1534 words) Published: November 17, 2008
Abstract:

This experiment studies the conservation of linear momentum through a carefully calculated collision. Two gliders were used on an air track with different weights to demonstrate what would happen as gliders with varying masses collided into one another. Throughout the experiment the measured values of the momentum before and after the collision were used to calculate the total momentum conserved.

Introduction:

The question of whether or not momentum is lost or conserved during a collision has been a topic of interest for many years. When two objects of equal mass or varying masses collide what is the outcome? The gliders are used to vary the weights and the air track is used to take away all variables of friction that could detract from the true outcome of the experiment.

We took the velocities of the different gliders as they were pushed through the photogates and used these numbers to determine what happened to the momentum as the two gliders hit. For the most case, this experiment shows that momentum is conserved throughout the lab and is simply transferred evenly from one glider to the next.

Procedure:

In this lab we began by setting up an apparatus that consisted of an air track with a blower and two gliders. The mass of the gliders was taken and recorded. If the masses were great than 5 grams apart a mass was added to equal out the gliders and keep them within the 5 gram measurement. Then the measurement of the picket fence was taken. The distance of the band spacing starting with each leading edge of the opaque strips is used to calculate the speed; our band spacing was .01m. The amount of time it takes the laser to pass through the opaque strips let the computer know how fast the object was moving.

Next we turned on the air and placed one of our gliders on the track. To test of if the track is even we placed the glider in a center spot and checked to see that it remained fairly still. Our track was actually slanted a little bit, which caused the glider to slide on its own down the track. To solve this problem we added a few sheets of folded notebook paper to raise up the lower end of the track until it was level.

Then we turned on DataStudio and chose the photogate and picket fence option. Since we were using two different picket fences and gliders the computer asked for the band spacing twice. Once the data was entered we place the two photogates around 30-40 cm apart on the center of the track. We had to test that the height of the photogate was set so that the picket fence would run directly through the beam and set off the little red indicator light that told us the computer was reading the fence.

Now the experiment begins. There are three separate experiments with five trials each. In the first experiment the weights of the gliders are relatively equal. The experiment starts by placing one glider in the middle of the two photogates (this is the target) and the other glider right in front of the two photogates on the track. (this is the incident) This incident is then gently pushed towards the target with its rubber band side facing towards the knife side of the target. Once the two gliders have passed through the photogates we pressed stop on data studio and recorded the velocities from the slope of the line. When both weights are equal the incident comes to a stop after it collides with the target and the target moves forward.

Results:

Linear momentum is equal to the product of the inertia (objects mass) and velocity of an object in a certain direction, and conservation of momentum means that none is lost. In this experiment, we tested the conservation of linear momentum between two objects that collide elastically. In these collisions, the total momentum before should equal the total momentum afterwards. This is directly related to and closely follows Newton’s first law which states an object at rest tends to stay at rest and an object in motion tends...