Part 2 Using Torque and Equilibrium to Calculate the Mass of a Ruler Remove masses m1 and m2 from the ruler Copy the measured mass of the ruler from Data Table 1 to Data Table 4 Copy the center of mass position on the ruler xCM from Data Table 2 to Data Table 4 Remove the tape securing the long string located at the center of mass of the ruler and slide the string to the 1000 cm mark on the ruler securing the position with more tape Note Hold the ruler steady so the system does not move until completing step 37 This position will now be known as x0 the pivot point location for Parts 24 Calculate the mass of the four washers using the average washer mass in Data Table 1 and record in Data Table 4 Attach four washers to one end of one of the short strings and attach the other end of the string to the left side of the ruler Slide the string with washers along the length of the ruler until the ruler hangs horizontally ensuring that the string is not twisted around the ruler either front to back or top to bottom Use the protractor to verify the string located at x0 makes a 90 angle with the ruler Record the ruler position of the washers to 001 cm in Data Table 4 Calculate the radial distances from the positions of the washers and the center of mass to the pivot point using the equation given in step 19 and record the results to 001 cm in Data Table 4 Calculate the torque due to the weight of the washers using the torque equation given in step 21 and record the result in Data Table 4 Calculate the magnitude of the torque due to the weight of the ruler acting at the center of mass using the equilibrium equation given in step 27 and record the result in Data Table 4 Calculate the mass of the ruler using the torque found in step 44 and the torque equation given in step 21 rearranged to solve for mass Record the result to 001 g in Data Table 4 Note Use the conversion factor 1 kg 1000 g Calculate the percent error for the mass of the ruler using the equation Error r m e a s r c a l c r m e a s 100 Record the percent error to 01 in Data Table 4