AT THIS POINT, IT IS A GOOD IDEA TO MAKE SURE THAT ALL QUANTITIES ARE EXPRESSED IN SI UNITS (kg, m and s)

1.  In the three columns to the right of data spreadsheet, label the headings v_A in cell F13, v_B in cell G13, and Δv² in cell H13. Do the same for cells F21, G21, and H21, respectively. Calculate v_A, v_B, and Δv² = v_B² - v_A² for each measurement.

HINT: The velocity at each point can be calculated using the width of the glider and the elapsed time. For example, in the case of point A, we want: v_A = w/Δt_A. Use the Worksheet to figure it out. In cell F14, enter: "= $F$9/D14". Select all the cells for the downward motion, from F14 to F18, and choose the menu under EDIT....FILL Down. Do a similar thing for point B data, beginning in cell G14. Note that the width of the glider is still at $F$9 in this calculation, but that here the time is in cell E14. Repeat these steps for the upward motion in cells F22 to G26.

To determine the difference in the squares of the velocities, v_B² - v_A², set up the following equation in cell H14: "= G14^2 - F14^2", and similarly in cell H22: "= G22^2 - F22^2". Once again, use EDIT....FILL Down to complete each table.

2.  If mechanical energy is conserved, the quantity v_B² - v_A² should be the same within the experimental uncertainty of the experiment for all measurements taken with the same value of H. Find the average value of v_B² - v_A² for motion down the incline, and enter it in cell H19.

HINT: In cell H19, enter the following: "= AVERAGE(H14:H18)". This is simply the average of all the values. Repeat for motion up the incline in cell H27.

3.  Calculate the difference h in the vertical heights of the track at A and B from the equation:

(4)

and enter it in cell G35.

HINT: The calculation can be done using the spreadsheet. In cell G35, enter: "= F11 * F29/F31".

4.  Calculate the change in potential energy ΔPE = m g Δy for the glider traveling down the track and the glider traveling up the track. Record the results in cells C39 and C40. Make sure you have the algebraic signs correct!

5.  In each case, use the average of the v_B² - v_A² values to calculate the change in the kinetic energy, ΔKE = (1/2) m (v_B² - v_A²). Enter the result in cells D39 and D40. Make sure you have the algebraic signs correct!

6.  Determine the change in the total mechanical energy, ΔE = ΔKE + ΔPE, in each case. Enter the results in cells F39 and F40.

7.  Calculate the work done by the non-conservative forces W_nc, such as kinetic friction. Enter the result in cell F43.

8.  Assume that W_nc = f_k d. Use this relation to calculate the force of kinetic friction, and enter the result in cell F46.