1. 2. 3. Objective: To use the conditions of equilibrium of a rigid body to measure unknown forces and obtain information about the physical parameters of the rigid body. Equilibrium of

Rigid Bodies Equipment: Meter ruler, a pivot to balance the ruler, a set of masses, stirrups to hold the ruler and the masses and an object of unknown mass. Theory: When a rigid body is in equilibrium, the following conditions are satisfied. (i) (ii) (iii) ΣFx = 0 ΣF, = 0 Στ = 0/n4. Procedure 1: AC raja 100 g Measured length = 6.35 cm The actual length of the ruler = 30 cm Calculate the conversion factor: Conversion factor = B Measure the length of the ruler shown on the computer screen and record it as: 30 Length measured on the screen This conversion factor is valid for the three parts of this experiment./n5. Procedure 2: W X G 10 cm A Balance the meter rule at its center of gravity G. Suspend a mass m = 20 g from the point A at a distance 10 cm from G. Suspend the unknown weight marked W from the other side of the ruler and balance the ruler again at it center of gravity by changing the position of the unknown weight. Measure the distance of W from G and record it as x. Repeat the experiment for m = 40, 50, 60, 70, 80 and 90 g balancing the meter rule each time at its center of gravity by varying the distance x. Tabulate the values of m and x. Interpretation of Data Set 2: (1) Draw a diagram showing the forces acting on the meter rule when it is in equilibrium for any general value of m. (ii) Take the torque of these forces about G and obtain an equation using the condition Et = 0 (iii) Write the equation in (ii) in the form y=mx. Identify the x and y variables and draw an appropriate graph. Measure the slope of the graph. Show on the graph how the slope is measured and record it with unit. (iv) Use the slope of the graph to obtain W, the weight of the object. Show your calculation steps./n6. Procedure 3: 100 g B 40 G Determine the center of gravity G of the meter rule by balancing it. Balance the ruler at the point A which is the 40 cm mark, by suspending a 100 g mass from the point B so that distance AB = x. Measure and record x. Suspend a mass m = 20 g from the center of (i) gravity and balance the ruler again at A by shifting the position of the 100 g mass. Measure and record the new distance x. Repeat the experiment for m = 40, 60, 80, 100 and 120 g suspended from the center of gravity and measure the length x each time. Tabulate the values of m and x. Interpretation of Data Set 3: Draw a diagram showing the forces acting on the meter rule when it is in equilibrium for any general values of m and x.