VI Lab Work, Force, Energy (Pulley Lab)

Within my first experiment in contemporary science our first lesson was about distance, velocity, and acceleration. My partner Raul and I created the Lego Mind storm VI which would travel a certain length at a certain time when programed. This experiment has been recently examined in my past posts. However, this week the lesson was on force, work, and energy. The virtual instrument (VI) can do many actions such as use sensors, drive, pull, light, etc. It was interesting to see how this device can be programed to not only drive, but also function as a pulley. Within this experiment we had the VI pull a heavy amount of weights. Each trial we would reduce the weight amount by 20 increments. As the experiment continued we discovered that as the weight decreases the battery discharge decreased along with the battery output. However, what increased was the speed of the weights being pulled and the time. An important fact about this experiment was that if the power level was kept the same the acceleration would be larger. Throughout the experiment we explored Newton’s 2nd law F=MA Force=Mass and Acceleration. As F+ (force)(increases) A+ (acceleration)(increases) We also confirmed that as Mass decreases the force remains the same and acceleration increases. However, if force decreases acceleration also decreases. As we collected data we used the formula force x mass = acceleration and noticed that the smaller the mass the smaller the battery discharge. Here is an attached URL of the chart with data my partner and I created and collected throughout the trials that proves our summary of the pulley experiment.

BatteryDischarge

 

 

 

Measuring Distance and Velocity

 Virtual Instrument Lab

                                                                               By: Raul Fernandez &Erin Beardsley

1.      Launch the VI wheel_rotation_straight.vi

2.      Study (with the instructor) the VI to understand how it works to measure the distance the wheels travel, and the speed at which the car travels.

3.      With a ruler measure the diameter of the wheel and compute the circumference of the wheel in meters (circumference= p*diameter).  Record that distance in the front panel of the VI.

To find % error= Distance ruler – distance to computer

                                     Average (distance ruler, distance computer

Wheel= 5.5 cm x .01 = 0.55 = x 3.14 circumference of .173

Small Wheel= 2.5cm x .01 =. 025 = x 3.14 circumference of .1

Run the VI and record:

 4.

 Time Power Level Rotation in degrees # wheel turns Distance

Ruler

Distance

Computer

Velocity

 

% error
1 sec. 75% 470 1.30556 22.1 22.4556cm 0.22456 21.092
2 sec. 76% 1143 3.175 53.8 54.6 .27305 54.2
3 sec. 77% 1892 5.25 89.7 90.3 .301 90

1.The wheel rotation (in degrees and in number of turns).  How are the degrees that the wheel rotated related to the number of turns of the wheel?

As the number of rotations in degrees increases in effect the number of wheel turns also increases. The rotation in the wheel increases every 700 degrees more or less the number of wheel turns is more or less 2 wheel turns per second added.

 2. The time it took for the wheels to turn (in seconds and milliseconds).  How are seconds related to milliseconds?

1,000 milliseconds is equal to 1 second. We increased our time from 1 sec. to 2 sec. and 3 sec.

 3. The distance the car moved.  How is the distance related to the number of turns.

The distance the car moves is related to how many turns because as the turn of the wheel increases the distance also increases. As the wheel turn increases the distance from computer also increased.

4.      Measure the distance with a ruler and compare your results with that of the VI.  What could account for the discrepancies?

            Discrepancies could be slight change or misreading of millimeters. Also the computer and ruler used to measure have different manual and automatic results. The distance that equals 22.1 cm, 53.8 cm, and 89.7 cm is different than the results of the computer, which were 22.4, 54.6, and 90.3. Also a point of error is that we increased the power level by 1% because we were intrigued to see the outcome of different velocities.