Final answer:
To find the weight of a meter stick using the principle of moments, create a balanced lever system and set up an equation using the principle of moments. By solving the equation, you can determine the mass of the unknown weight and the normal reaction force at the fulcrum.
Step-by-step explanation:
To find the weight of a meter stick using the principle of moments, we need to create a balanced lever system. Using the given information, we can set up a free-body diagram for the meter stick and identify the five forces acting on it: w₁, w₂, w, w₃, and Fs. We can choose a pivot point at the support where the meter stick touches and set up an equation using the principle of moments to find the weight. In this case, the mass of the meter stick is 150.0 g, and the masses on the left of the fulcrum are 50.0 g and 75.0 g. Let's denote the mass of the unknown weight as m₃. When the system is balanced, the total clockwise moment about the pivot point is equal to the total anticlockwise moment. By setting up an equation using the principle of moments, we can solve for the mass m₃. The normal reaction force at the fulcrum can also be calculated by summing the vertical forces acting on the meter stick, as the system is in equilibrium. By substituting the known values and solving the equation, we can find the normal reaction force at the fulcrum.