22-May-2017 Finding the moment of inertia of Uniform Triangle

James Okamura
Rodrigo Uribe
Daniel Guzman

May 22, 2017

Introduction
In this lab, we want to apply our knowledge of moment of inertia to determine the moment of inertia or uniform triangle.

22- May - 2017 Moment of Inertia and Frictional Torque

James Okamura
Daniel Guzman
Rodrigo Uribe

May 18, 2017
May 22, 2017

Introduction
In this lab we want to know how to determine the moment of inertia of the system and determine the frictional torque.
Procedure
We first made measurements of various portions of our apparatus. The mass was already given to us, it was labeled on to the apparatus in grams. We measured the "thickness" or height and diameter of each cylinder using an apparatus.

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With this info, we converted the mass to kilograms and the radius and height measurements to meters and we calculated the moment of inertia of this apparatus. We were able to do this by calculating the individual parts of this apparatus, which are all rods. But before we did that, we have to determine the individual masses by taking proportion into consideration. 

For the next part of this lab we wanted to determine the angular acceleration of the apparatus.We were able to do this by recording the apparatus in motion using a smart phone. Then we open it in Logger Pro under video analysis. We figured out the position by putting dots around the circumference. From there we were able to determine the Vx and Vy of the apparatus by taking the slope of the graphs in the x and y direction. We were able to get the magnitude of the velocity by applying Pythagorean theorem. Next if we divide that radius, we can get an omega vs. alpha graph and we took the slope of that. We were able to get the angular acceleration we needed and we were able to calculate the frictional torque. 

For the last part of the lab we want to determine the time it takes for a cart to travel 1 meter, that is wrapped around the apparatus by a string. We first calculate the acceleration of the system than we were able to determine the time it too using kinematics into consideration. 

Then we wanted to determine the angle of the ramp by using trignometry. 

Conclusion

In this lab, I learned that we can calculate the moment o inertia of any object and with that find torque that is called by the system and the acceleration of the object.

15-May-2017 Angular Acceleration Part 1

James Okamura
Daniel Guzman
Rodrigo Uribe

May 15, 2017

Introduction
In this lab we were trying to determine what variable will affect angular acceleration, the hanging mass, the change of the spinning disk or the pulley.

Procedure:
We first made sure that all of our lab equipment was clean. From there, we made sure to take some measurements of the lab equipment as shown in the data table below.  We measured the mass of each equipment using a scale and we measured the diameter using a caliper.

We first plug the power supply into the Pasco rotational sensor. If there is a cable withe the yellow paint or tape, connect only that cable to the Lab Pro at Dig/Sonic 1, so the computer is reading the top disk. If the cables are the same, connect them both. You will need to discern which is measuring the top disk and ignore the other sensor. 

Set up the computer. Open the Logger Pro. There is no defined sensor for this rotational apparatus so we will need to create something that works with this equipment. Choose Rotary Motion. There are 200 marks on the top disk, so you will need to set the Equation in the  Sensor Settings to 200 counts per rotation. When you collect data, you can see graphs of angular position, angular velocity and angular acceleration vs. time. the graph of angular acceleration vs. time is useless due to the poor timing resolution of the sensors. Do not use this graph. 

Make sure the hose of the clamp on the bottom is open so  that the bottom disk will rotate independently of the top disk when the drop pin is in place.

Turn on the compressed air so that the disks can rotate separately. You will not so much air that you op the hose from the air source, but enough to keep things smooth. Set the disks spinning freely to test the equipment.

With the string wrapped around the torque pulley and the hanging mass at its highest point, start the measurements and release the mass. Use the graphs of angular velocity to measure the angular acceleration as the mass moves down and up. 

By increasing the hanging mass, we can see that the average angular mass increases. By increasing the rotating mass we can see that the angular acceleration decreases. We can see that by increasing the radius of the pulley, the angular acceleration increases. 

Also in this lab we want to know the moment of inertia of the system. We can do this because we know we can calculate it by adding the various parts of each equipment inertia up. 

Conclusion

In this lab I learned how various variable can affect angular acceleration in certain ways whether it be increasing or decreasing. I also learned how we  can find a the moment of the system. 

26- April - 2017 Collisions in Two Dimensions

James Okamura
Alejandro Rodriguez

April 26, 2017

In this lab, we want to see that in a two-dimensional collision and see if the momentum and energy is conserved within the collision.

We first get two balls which has relatively same mass and we put it on this glass table apparatus. On top of this apparatus is where you can put your phone to record the collision after you have changed the frame per second and to slow recording function. Also make sure the glass table is leveled, you can adjust it by changing the 3 legs of the table. Now place one of the ball on the table directly under the phone. Have your partner press record while you rolled the other ball so that it collides with the balled that was stationary and it goes in two different directions.

Now go get a laptop and open the video, edit the video so that it is the portion when the collision happens and nothing more. Now open Logger Pro and open that video file. Now you change the frame per second and starting graphing the two balls with the same masses velocities in the x-direction and the y-direction for the respective masses. Now do a linear fit to get the velocity value.

After doing this you create a new columns Xcm and Ycm and graph that . You also make graph which includes the Vxcm and Vycm.

After doing all this you want to do the same procedure again but with two different masses.

This is the collision between two different masses of balls.

 The red and blue graphs shows the velocity in the x-direction and y-direction of the lighter mass of the two balls. The green and the brown graphs are for the bigger mass of the two balls velocity in the respective direction.

 This is the center of mass of the two balls.

This is the velocity of the balls with respective to the two balls.

Conclusion

I believe that in either part of this lab that momentum and energy is conserved. However there are some outside force as friction between the glass table and the balls that we need to take into account. In this lab I learned the concepts of momentum in two dimensions.