19 - April - 2017 Impulse Momentum Activity

James Okamura

Alejandro Rodriguez

April 19, 2017

Introduction

In this lab we want to see if the impulse momentum theorem can be observed. We want to test this theorem by doing one experiment in a elastic collision and inelastic collision. In the elastic collision, we do this by attaching a spring on the system and when the cart collides ( due to us providing a small force to move it) it will hit the spring and bounce back. We do the inelastic collision by having clay attached to the end of the system so when the cart collides it sticks to the clay.

We first set up the apparatus so that on one end of the track had the motion sensor and at another  end of the track we set up cart with spring attach to its end so when the cart we push hits that spring it would bounce back for an elastic collision. As always we calibrate and set up the motion and force sensors. We put the force sensor on the cart. We put the cart on the track and we start the experiment. We want to see if the velocity vs time graph and the force vs time graph would produce the same results.

When we try calculating impulse using the Velocity vs, Time graph and taking the integral of the Force vs, Time graph, you can see that we got two different results. I want to believe the some of the force exerted by the spring on the cart was lost when it had happen.

In this next part of this lab, we did the same thing except, instead of the spring, we had clay attached to the end so this will model an inelastic collision. 

When we compare the result of our calculated impulse value compared to the integral of the Force vs. Time graph, we can see that the impulse-momentum theorem can be applied here as we got relatively similar values in this inelastic collision,

In this ab I learned that we can model both Elastic and Inelastic collision and see how the impulse-momentum theorem can be applied. That we can test this theorem using our knowledge of momentum and impulse. Although when we did our Elastic collision, our calculated value compared to the integral of the Force vs. Time graph were different. 

17 - April - 2016 Magnetic Potential Energy

James Okamura
Alejandro Rodriguez

April 17, 2016

Introduction
In this lab, we wanted to test that conservation of momentum applies to this system. We have this system in which acts like an air hockey table that will act like a frictionless surface. So when we put a cart and give that cart a push, it will glide down to the edge of the system and bounce back due to the magnetic repulsion caused between the magnetic on the end of the cart and on the system.

In this lab, we first got a phone app that can measure degrees the system is raised from the horizontal, and place it flat from the horizontal.

Next, we raise the system some degrees, turn on the system and gently push the glider so that is slides down the ramp and get push back by the end of the magnetic repulsion and let the cart glider comes to an equilibrium distance. We record the degrees of how much the system was raised and the distance the cart glider has traveled back due to the magnetic repulsion. We repeat this process at least another 4 times and record the distance from the end of system and degrees. We then convert the angle from degrees to radians and then use that to calculate the force.

In this next part of the lab, we attached an aluminum reflector on top of the cart and weighed the whole cart. 

Next we placed the cart relatively close to the end of the ramp and turned on the air. We ran a motion detector. We then determine the relationship between the distance the motion sensor reads the distance we measure between the two magnets, 

We then set the motion to record 30 measurement per second. Then we created a new column for this separation by magnets measured by the motion detector. 

We then start with the cart at the other end of the cart, start the detector and push the cart with a gentle push.

We then made a graph that had the work done by the magnets and the kinetic energy. 

The above graph shows the energy caused by the magnets and the kinetic energy. When you add the energy of both these graphs, you can see the total energy, the energy conserved by the system. 

In this lab, I learned that energy is conserved by the system. That whatever energy you start out with is what you should end with unless there's an external force ( in this case there was none). I learned how we can calculated the work done by the magnets by using a free body diagram. 

10 - April - 2017 Work- Kinetic Energy Theorem Activity

James Okamura
Jin Im

April 10, 2017

Introduction
In this lab, we are trying to explore the relationship between work done by and kinetic energy of an object. We can do this by having a cart on platform with a string attached to it with a hanging mass to the other end of the string.

We first gt a track and we put our cart with the force sensor on it. Then on one end of the cart we attach a string to it and on the other end of the string we attach 50 grams of hanging mass. On the other end of the track we put a motion sensor on it. We calibrate the force sensor.

Next we open the document as posted in the lab manual and we put the cart as shown in the diagram and click record, and let the experiment began. We get a graph like this .

We get this graph after we selected the Force vs, Time graph, changing the x-axis and y-axis and then taking the integral of the graph. our integral value we get is 0.1842 while our kinetic energy value is 0.186 J. This is true because the only work the cart is doing is kinetic energy when the cart goes at some velocity after the cart is let go causing the hanging mass to pull the cart forth.

In this next part of the lab, we want to attack a spring to the end of the force sensor and stretch and let it go after we stretch the spring a certain distance. 

The set up is the same except for the opposite end of the motion sensor that is where we attach one end of the spring and the other end to the cart. We then stretch the cart a certain distance and let it go. In this lab, not only do we have work done by kinetic energy but also with the elastic potential energy. 

The above graph is the integral of the kinetic energy graph and the other one is the graph cause by elastic potential energy. 

This is the graph we have watched where a professor pulled a rubber band back. When you see integration of this graph and the work done by Kinetic Energy, they are quite similar.

In this graph I learned that we can learn and use what we know of the Kinetic Energy Theorem. We have seen this application when doing this lab. 

5 - April - 2017 Work and Power

James Okamura
Alejandro Rodrigues
Rodrigo Uribe
Daniel Guzman

April 5. 2017

Introduction
In this lab, we were trying to determine how much energy ( in joules ) we use in our daily activities such as lifting, running and walking that we do everyday. This is important to know as we use up a lot of energy in the daily activities we partake each day and we want to determine how we use up the energy in our bodies.

In this lab, we set up this pulley-like system at the to of balcony on the second floor of Building 60 outside. With this we run a rope through it and have one end of rope attached to a backpack that has some weight to it and we lift it. We also record the time it took for us to lift the backpack from the the ground level to the edge of the balcony.

In the next part of the lab, we timed ourselves where we would walk and run up the steps from the ground level to the second floor. We also measured how high each step is with a meter stick and counted how many steps there are. By multiplying those two values and applying trigonometry to it we can determine the distance we travel.

Procedure

We first set up the pulley on a board and have one person put their feet on this board. Next we put a rope through the pulley. We attach one end of the rope to a backpack which have some weights inside ( for our experiment, we put in 9 Kg) . Next, we get ready by putting gloves on ( to prevent rope burn ) and holding on to the other end of the rope. We start pulling the rope to the height we want to pull to, which this case was the edge of the balcony of building 60. While someone is pulling the backpack to its desired height, your partner is measure the time it takes (in seconds ) with a stopwatch.

We later on walk up the stairs ( which we measure the height of a step and multiply by the number of steps). We timed how long it took to climb the steps.

After that, we later run up the steps. Time how long it took.

We calculate the power output for lifting, walking and running respectively.

Conclusion

 I learn in this lab is that, I can apply the knowledge i have in calculating work and power to determine how much work and power I do when doing everyday things such as lifting something heavy or covering long distances by walking or running.

5- April - 2017 Centripedal force with a motor

James Okamura
Daniel Guzman
Rodrigo Uribe
Alejandro Rodriquez

April 5, 2017

Introduction
In this Lab, we are trying to figure out the relationship between theta and omega.
In this lab, we start with this apparatus that looks like a tripod and has a motor on the top. Connected to the motor has some rod. At one end of this is a string attached to it. The other end of the string has a mass to it. Put a piece of tape to the block.  From a certain distance you set up a ring stand with photo gate on it , and you adjust it so the tape will pass through the photo gate. From this you can determine the time it takes to have one full revolution.

We can get the angle  from looking at the right triangle with hypotenuse L and height H-h.

We can get the rotational speed by collecting how long it take to have ten rotations and divide that by ten.

We measure the height of the apparatus and how high off the ground the hanging mass is.

With this given info, we can calculate the rotational speed by applying free body diagram and by using the the period of 10 rotations.

After collecting data after 5 trials, we can calculate its respective rotational speed.

We can now compare the model and rotational by putting it on a graph and getting a linear fit.

We can then calculate the percent error by using the the slope of our graph as the experimental and the actual value of rotational speed as 1 radians/ second.

Conclusion
In this lab, I learned that we can apply our knowledge of Centripedal Force to real life application. I learned that although there is not that much difference from our model and actual omega, I think I would calculate omega by using the period of rotation since I would not get too much of an error.

29- March - 2017 Centripetal Force vs. angular frequency

James Okamura
Daniel Guzman
Alejandro Rodriguez
Rodrigo Uribe

March 29, 2017

Purpose
In this lab, we are trying to learn the relationship between centripetal force and angular speed.

Introduction
In this lab,we are trying to figure out the relationship between the angular velocity, the mass of the object in motion and radius ( or the distance the object is from the center).

Procedure
First, we set up our apparatus as shown below.

 Then we put a piece of tape on the rim of the disk, so the that it passes through the photo gate. This will help us determine the rotational period of the disk.
Next, we put a wireless force sensor on the disk and then turn on the disk so it can go constant speed, zero the force sensor. Now let the come to a constant speed and record that. We tied a string to the center at one end and at the other end, we tie it the mass. When collecting data we want to collect data in such a way that :

• we have a variety of masses at fixed constant speed and radius. ( which we can see how mass have an effect when mass changes)
• have the same mass at the same constant speed but with a different radius each time ( how the change in radii affect our data)
• have the same mass and same radius but at different rotational speeds ( we can get this by adjusting a voltage on our power supply. This shows the effect of changing rotational speed)
  

We were able to get the angular frequency by subtracting the period it took for 1 rotation of the disk from when disk rotated 10 times from the initial rotation. Then we divided by 10 ( since its 10 rotations). Next we divided this value we got from 2 Pi, to get our rotational frequency.

After we got out measurement, we decided to graph by letting one  values out of the three ( mass, radius and rotational speed) to be constant with Force and  graph that, causing the slope to be one of the respective values

In this case, we use the various mass values and graph that against Force which would help us get the angular velocity times radius to be the slope

In the next case, we put radius against force and graph that to get the slope to be (constant m, and angular velocity).

Next, we had the angular velocity vs Force graph and we graph this. The slope of this line would be (constant m,r). 

Conclusion

I believe that since there was some discrepancy when recording the data for angular velocity, we cannot say that the Force vs. W graph is accurate since the slope should be constant. We can fix this by changing the W here with the ( m,r ) values to get a constant slope. I learned in this lab that if we change one of the variables in rotational motion, we can determine the other two variables by the methods we used in this lab. 

23 - March - 2017 Modeling Friction Forces

James Okamura
Daniel Guzman
Alejandro Guzman

March 23, 2017

In this lab, we were trying to compare how friction is different when an object is at rest or when it is motion. Also we were trying to see the difference between friction on an incline plane or horizontal, flat plane.

In the first part of the lab, we had gotten a mass block and put it on the this board ( that we have cleaned) with the linoleum side. After that we tied a string to it and tied the other end to another hanging mass and we continue adding to the hanging mass, until the block finally moved. After we have done that, we recorded the hanging mass, the mass of the block moved. Did the same procedure over again after we put the block at the initial position but with weight added onto it. We did this again until it had a total of three masses and four masses, and recorded the masses. by using the logger pro, we were able to fine the coefficient of friction for respective masses and using that and various mass we are able to produce the graph below.

We were able to find our slope to 0.3096 which means that our coefficient of static friction between the block and the board to be 0.3096 due to the slope of mass vs. coefficients graph above.

In the next part of the lab, we pulled the string that was attached to the rope and we pulled it in front of the logger pro sensor. We did this again after applying more weight to the block and pulled it from the same initial spot and at constant speed. We did this again another two times and we were able to get a consistent coefficient of static friction that was graphed due to the logger pro program.

In the next part of the lab, we put a phone after it goes on this app that measure the angle from the horizontal and the block, we slowly raise the board until the block starts sliding down. We recorded that angle to 27 degrees. With this information, we went and tried to calculated the coefficient of static friction. 

In the fourth part of this lab, we attach a motion sensor on top and using that, we raised the board to the same angle as before where the block would move. The motion sensor which is connected to the laptop, using the logger pro program help us the determine the acceleration at which the block was going at. Using all this info, we were able to calculate the coefficient of kinetic friction as shown in the picture below.

In the final part of the lab, we put the board back down on the table and attach a piece of string to the block. we attach the other end to a hanging mass. We wanted to see if we can determine acceleration of the block if we put enough mass to the hanging mass. So we went and put enough mass so the block will accelerate and the logger pro sensor captured how fast it was accelerating. In the picture below, we tried calculating how fast the block was moving. 

In this lab, we were able to learn how to determine static and kinetic friction. I believe that there was error in some aspects as in the lab, as I do not believe to have pulled the block at constant speed as i would have like to. I also believe that if given more time, we would have been able to reduce our percent error more.