1.  Place one of the pulleys at 180° and suspend a total (including the weight holder) weight of 2.94 N (300 g) from the string passing over the pulley. This will be called force A.

2.  Place a second pulley at 90° and suspend a total weight of 1.47 N (150 g) over this pulley. This will be called force B.

3.  By trial and error, determine the position of the third pulley and the force in newtons necessary to exactly balance the other two forces. This third force is the EQUILIBRANT. It is opposite in direction and equal in magnitude to the RESULTANT of the first two forces.

4.  Open the Worksheet and fill out the header information. Enter the forces used and their angles in the PROCEDURE 1 area in the DATA table beginning at cell C9.

5.  Open the Graphics Sheet.

Use the STRAIGHT LINE graphics tool to draw a vector to represent FORCE A. A convenient scale is to let 1 N = 2 cm on the drawing. To draw the vector:

• Delete any initial entries on the screen (origin and line segment).

• Select the Tools tab, then Arrows, and then, under Location, check the "Start" box. (This will make the line segments into arrows.) Set the Location Offset to 0.

• Use the menu on the side to input the appropriate length and angle of the vector.

6.  Likewise, draw FORCE B. (Make sure to use the correct scale.) FORCE B should be positioned to show the addition of A and B (tip to tail).

7.  Draw the RESULTANT with the STRAIGHT LINE tool. Do NOT use the SHIFT KEY in this process! It is a vector that begins at the ORIGIN and ends at the TIP of the transferred FORCE B vector.

8.  Click on the RESULTANT. Observe and record the magnitude (be sure to convert back from the drawing scale to newtons) and direction of this force on the Worksheet where indicated in ANALYSIS 1-A table in cells C14:C15.

9.  Compare the magnitude and direction of the RESULTANT with the values measured for the EQUILIBRANT. Make sure you convert from the drawing scale back to newtons! Find the PERCENTAGE DIFFERENCE between the two values in each case, and enter in cells E14 and E15. Be sure to add 180° to the RESULTANT to compare the directions. Use the spreadsheet calculator to do the computation.

10.  Calculate the x- and y-components of FORCE A and record them on the Worksheet in ANALYSIS 1-B at cells C19:C20. BE CAREFUL about the algebraic signs of the components.

HINT: you can let the spreadsheet do the work to compute the x-component by entering in cell C19 the following: "= C9 * COS(C10 * PI()/180)". The angle in degrees is multiplied by π/180 to convert it to radians. In cell C20, for the y-component enter: "= C9 * SIN(C10 * PI()/180)".

Repeat the same resolution into components for FORCE B in cells D19:D20.

11.  Add up the components separately to obtain the x-component and the y-component of the RESULTANT.

12.  From the components of the RESULTANT, calculate the MAGNITUDE and enter its value in cell E22.

13.  Compare the MAGNITUDE that you have computed with the MAGNITUDE of the EQUILIBRANT in cell D14. Find the PERCENTAGE ERROR and enter it into cell F23.

14.  Return to the Graphics Sheet and choose under EDIT.....SELECT ALL. Select EDIT....COPY and then on the Worksheet, EDIT....PASTE at cells A25:E41.

♦♦♦DO NOT RESIZE THE GRAPHICS OR YOU WILL GET A DISTORTED GRAPH!♦♦♦
 

1.  Return to the Graphics Sheet , and choose under EDIT.....SELECT ALL, then hit Delete.

2.  In this procedure, you are to determine the equilibrant of three forces by experiment. Place the first pulley at 0° and suspend a total weight from it of 0.685 N (70 g). Place a second pulley at 200° and suspend a total weight of 1.47 N (150 g) over it. Place a third pulley at 60° and suspend a total weight of 1.96 N (200 g) over it. By trial and error, determine the equilibrant. Record the magnitude and direction of the three forces and the EQUILIBRANT in cells C51:F52.

3.  Repeat the same procedures as before, except now you will have three forces to find the resultant for. As before use the graphical method to find the MAGNITUDE and DIRECTION of the RESULTANT by using the DETAILS data and record on the Worksheet in cells C56:C57. Compare with the measured MAGNITUDE and DIRECTION of the EQUILIBRANT and compute the PERCENTAGE ERROR in cells E56:E57. Be sure to add 180° to the RESULTANT to compare the directions.

4.  Calculate the x- and y-components for FORCE A. Record its x- and y-components on the Worksheet in ANALYSIS 2-B. BE CAREFUL about the algebraic signs of the components.

Repeat the same resolution into components for FORCE B and FORCE C.

Perform the calculation to find the components of the RESULTANT and from these values, enter the MAGNITUDE of the RESULTANT in cell E64. Use the spreadsheet functions whenever feasible. Compare with the MAGNITUDE of the EQUILIBRANT, compute the PERCENTAGE ERROR and enter it in cell F65.

5.  Return to the Graphics Sheet and choose under EDIT.....SELECT ALL. Select EDIT....COPY and in the Worksheet, EDIT....PASTE at cells A67:E84.

♦♦♦DO NOT RESIZE THE GRAPHICS OR YOU WILL GET A DISTORTED GRAPH!♦♦♦