Aim: To determine the mass, m, of a Bahamian 5-Cent Coin Using the Method of Moments Theory: 1. State the definition of "moment" (torque) about a pivot or fulcrum) [1] 2. State the requirements for an object (e.g. a metre rule) to be in rotational equilibrium (i.e. state the Law of Moments). [1] 3. Define centre of gravity [1] Apparatus: [3] Diagram: Based on the Procedure described on the next page, label the diagram below and write a sub-title on the Figure 1 line. Make sure you label the names of the following (including direction arrows representing forces): Bahamian 5-cent coin (of mass m); Bahamian 25-cent coin (of mass M); ruler; fulcrum; the point B at the fulcrum; weight of the 5-cent coin (mg); weight of 25-cent coin (Mg); the distances d and D at balance. [4] Figure 1: [1]Procedure: 1. Place a pencil or ball-pen of hexagonal cross section on a horizontal surface (e.g. a table]. Carefully balance a 30-cm ruler on the flat part of the pencil and note carefully where the center, B, of the point of balance is located on the ruler. [This point on the ruler is its center ofgrovityJ Keep the ruler pivoted at this point on the ruler [the "fulcrum") throughout the experiment. 2. Place the center of a 25-cent coin of mass, M, a suitable distance, D, from the fulcrum B [e.g. 5.0 cm]. (Note: the mass of the Bahamian 25-cent coin was found on a lab beam balance to be 4.9 g] 3. Slide the 5-cent coin of mass, m, to a distance, d from the coin's center from the fulcrum, on the opposite side of the fulcrum B, so as to balance the rule. 4. Calculate the mass, m, using the W cl = M D (which is derived from the equation of moments M g D = m g d}, using your data. {See below for the space where you should show your calculation). Record your data and results in the table below. 5. Repeat steps 3 and 4 using D = 7.0 cm and record these results also in the table below. Results: {Make sure toinsertunit svmbolsford and m.] [5] Mass M/g Distance from Distance of m from Calculated value pivot D/cm pivot d of m _ Average calculated m Calculations of n1 [4] + Discussion Describe ONE possible source of experimental error: [1] Conclusion: [2]