Open up the Interactive Physics file. You will see the set up that is described above. Note also that there are two slide controls which allow you to vary the mass of each block, and two push buttons to RUN and RESET the simulation. Two readout displays are presented to display the velocities of each mass, along with a numerical readout of the elapsed time. You will notice an arrow at the top left of each velocity display. This arrow allows the observer to choose the mode of data display. Select the GRAPH readout mode from the menu and leave it in that form for the time being. We choose to look at the velocity of the masses because in this case we expect the acceleration to be constant, and its value can easily be determined from velocity data.
Sketch the plots obtained for the velocity of each mass. Be sure that the scales on the x- and y-axes are recorded accurately. Take a break and answer the following questions by linking to the Newton's 2nd Law Worksheet. Be sure to fill in the header information. Answer Questions 1 through 4 on the Worksheet.
2. Go back to the Interactive Physics window and RESET the simulation. By selecting the menu on the velocity displays, change the format to digital for the velocity of each mass. RUN the simulation again. Determine the acceleration of each mass by using the final velocity for each mass, and elapsed time data that the simulation provides.
Switch back to the Worksheet and go to the heading labeled PART 1. Five data columns are set up on the spreadsheet in cells B36:I41. Headings for the data to be recorded are indicated. In trial 1, record the two mass values, the change in velocity for each mass during the run, and the elapsed time on your data sheet. There are 3 more data columns, and you need to label them accordingly. In the first one of these, put down the result of your determination of the acceleration of mass #1. In the second, put down the result of your determination of the acceleration of mass #2. Finally, in the third, put down the value of the acceleration calculated using Equation (1). Then answer Questions 5 and 6 on the Worksheet.
3. Keeping mass #1 at 1.0 kg, repeat for the following settings of mass #2: 4.0 kg, 3.0 kg, 2.0 kg, and 1.0 (trials 2, 3, 4 and 5). Be sure to hit the RESET button before changing the mass value with the slide control. Fill in the data on your data sheet in each case above. It should include the mass values, the change in velocity values, the elapsed time value, the measured acceleration values, and the calculated acceleration value.
4. Reset mass #2 to 5.0 kg and set mass #1 to 0 kg (or as close as you can get to zero). Repeat the procedure above and record the data (trial 6).
5. Below the first table is a second tablewith two data columns covering cells C45:D50. In the first of these, find the difference between the measured and the calculated values of the acceleration for all mass values. In the second column, find the percentage error in this measurement. Finally, answer Question 7 on the Worksheet.
Load the Interactive Physics file. The setup is much the same except now the output is in the form of three graphs in which the x-position, the velocity and the acceleration of mass #1 are plotted.
3. Print out the Worksheet and use it to develop your lab report.