Lab 15: Collisions in two dimensions
Author: Tian Cih Jiao
Lab Partners: Weisheng Zhang, Kitarou
Date: April 19, 2017
Look at a two-dimensional collision between a steel ball and another steel/aluminum ball and determine if momentum and energy are conserved.
Set up:
A iphone 5 with camera, two same steel balls, and a aluminum
we put our phone above the table, then capture two video.
First one is steel ball collision with steel ball, second one is steel with aluminum.
Measured data:
The mass of the steel ball: 0.071 kg
The mass of the aluminum ball: 0.01 kg
The length of the glass table: 58.6 cm
For the first one, we used steel with steel collision. we added three point series and set the origin on the collision point.
The mass of the steel ball: 0.071 kg
The mass of the aluminum ball: 0.01 kg
The length of the glass table: 58.6 cm
For the first one, we used steel with steel collision. we added three point series and set the origin on the collision point.
Analysis:
First collision graph:
momentum before collision: m*vx1 = 0.033, m*vy1 = -2.84*10^-4
momentum after collision: m*vx2+m*vx3 = 0.028, m*vy2+m*vy3= -7.1*10^-3
KE before collision: 0.5*m*(vx1^2+vy1^2)=0.0077J
KE after collision: 0.5*m*((vx2+vx3)^2+(vy2+vy3)^2)=0.0059
For first collision, there is some errors that makes the initial result and final result are not very close.
Second collision graph:
momentum before collision: m1*vxi=0.054, m1*vyi=-0.0038
momentum after collision: m1*vxf+m2*vx2=0.0535, m1*vyf+m2*vy2=-0.0061
KE before collision: 0.5*m1*(vxi^2+vyi^2)=0.02J
KE after collision: 0.5*m1*(vxf^2+vyf^2)+0.5*m2*(vx2^2+vy2^2)=0.0195J
For the second collision, the result is much more closer, which means this one has less errors.
Conclusion:
In this lab, we wanted to find out the conservation of kinetic energy and momentum. However, there are many errors in this lab. Our video is captured by a 30 fps iphone 5, so when we were adding points for the graph, it's very hard to add points on the correct place. Then our velocity have errors too.
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