Physics 4A Lab #4: Working with Spreadsheet

Purpose:

 The purpose of the lab was to get familiar with the electronic spreadsheet by using them in some simple calculations.

Equipment:

Computer with Excel software

Procedure:

The first part was to create a simple spread sheet that calculates the value of the function f(x)=Asin(Bx+C). We chose values for A=5, B=3 and C=∏/3 representing amplitude, frequency and phase. Then we made two columns, one for "x" another one for “f(x).” on the cell bellow "x" we entered zero, on the cell below "f(x)" we entered an equal sign and followed by the formula above. We created a column for values of “x” running up to 10 radians in increments of 0.1 radians and by using the same feature we created the values for “f(x)”. Our next step was to copy the data from the two columns in the spreadsheet to the graphical analysis program and create a graph matching the corresponding data. We selected a portion of the graph; then we used sine curve fit from the list of possible functions. Comparing the values for A, B and C displayed by the computer to the spreadsheet’s were very similar. A and B values were exactly the same, C value was off by 0.47. See tables bellow.

 

We repeated the same process for another spreadsheet that calculated the position of a freely falling particle as a function of time. This time our constants included the acceleration of gravity, initial velocity, initial position and the time increment, so we used the values g=9.8m/s/s, Vo=50m/s, Xo=1000m and for time intervals ∆t=0.2 s. the equation used in this case was quadratic y= A+Bx+Cx^2 where A= g acceleration, B= initial velocity and C= initial position. Again the values for the variables that we started with in the spreadsheet match the values from the graph. See tables bellow.

Conclusion:

The hardest part of the assignment was to figure out how to enter the equation in the spreadsheet so it could give us the right data. We made several attempts to match the value of the original variables to those obtained from the graphical analysis and they did not match which meant that we made a mistake on setting up the equation. We had to go back several times and fix it until we got it right. For us the biggest source of error did not know how to use Excel software.

Other sources of error or a way in which the calculation could have been more precise could be by making the increments in time smaller for example instead of using 0.1 s; we could have used 0.01 s or 0.001 s. In my opinion the most important step was to correctly set up the equation in the spreadsheet and to identify the right function to curve fit the graph. Through this lab I learned the importance of knowing how to use tools that will allow you to make calculation faster and more efficiently to obtain/measure data for each experiment.