We know that moment is the rotational effect on the force of a body over a fixed axis. These moments are simply such as pushing a door open. Therefore, if you carefully observe the force applied to the door, this force is called moment force. If you are clear about the force that is applied then you must be knowing about the principle of moments equation. Don’t worry if you do not, we are here to explain to you in detail the principle of moments example which will make clear all doubts.

**1. What is the Principle of Moments?**

If all applied forces and moments balance out and there is no net force or moment on the body, the body is said to be in equilibrium. If the net moments exerted across it in both the circular and rotational directions are zero, it is said to be in rotational equilibrium. The rotational mechanics includes this analysis of moments and equilibrium as a fundamental concept. This study aids in establishing how hard bodies move as a consequence. This has been described with the principle of moments equation, lets us see how. (See What is Pulling Force?)

**2. What is the Formula for the Principle of Moments Equation?**

The formula is Moment of force = F × D. Sum of anti-clockwise moments = sum of clockwise moments.

**3. What is the Principle of Moments Equation?**

The principle of moments equation states:

m_{1}d_{1} + m_{2}d_{2} = m_{3}d_{3} + m_{4}d_{4}

**4. Is the Principle of Moments Equation also Known as Varignon’s Theorem?**

**Yes**, Varignon’s theorem is another name for it. He was a mathematician from France. He stated that the total of the various moments along an object’s axis equals the net moment along that axis. Check out Why is it Important to know the Properties of Matter?

**5. What is the Principle of Moments Example in Daily Life?**

The best principle of moments example is the force exerted while opening the door. Another great example is when we make use of devices such as levers.

**6. What is the Principle of Moments Example in Equation?**

Let’s say for example there is a 300 m ruler that is pivoted over the middle point which is a 50cm point. If the weight of 20 N is hanged from the 30cm mark and the weight of 10 N is hanged from the 60 cm mark. Will the meter ruler remain the same or not?

We know that the principle of moments states that the object is in rotational equilibrium and then

Anticlockwise moments = clockwise moments

Therefore, the length of the lever arm = 50 cm – 20 cm = 30 cm = 0.30 meters.

Since the distance from the lever arm’s midpoint, where its balanced force is exerted, determines its length = 20 N

Therefore, Anticlockwise moments = Lever arm × Force applied

= 0.30 × 20 = 6Nm

Further for clockwise = 60 – 50 = 10cm

Lever arm × Force applied = 0.10 × 30 = 3 Nm

Therefore, the meter rule remains **balanced** since it is under rotational equilibrium.

**7. What is the Application of Principle of Moments?**

The application of principle of moments states that the sum of clockwise moments for a pivot is equal to the sum of the anticlockwise moments of the pivot when the body is in equilibrium. Must read What are Energy Transfer Examples?

**8. Where is the Application of Principle of Moments done?**

Now that you understand the principle of moments equation, let us move on to the application of principle of moments. They can be done in levers, common steel yards, and lever safety valves.

### 9. How is Beam Balanc**e made with the Principle of Moment?**

When two pans with slightly varied weights are loaded, a beam balance will come to rest at an angle to the horizontal. A pivot holds the beam in place at a single fixed point. The net force exerted by the two weights around this fixed single point is nonzero at the equilibrium position. The entire system stops rotating around the fixed point because the moment is balanced. (See Magnetic Compass is used to Find What?)

**10. Are Seesaws an Example of the Moment of Force?**

**Yes**, we are aware that these are seesaws with weights on both sides. These weights enable them to ascend and descend. This is a result of the seesaw’s weight and the amount of force being applied to it. The seesaw’s pivot is a spring that is located in the center of the device. As a result, you can observe that the seesaw’s upper side rises while its lower side descends. On the seesaw, these forces cause them to alternately move in various directions.

**11. What is the Right Hand Rule of Moment?**

The clockwise and anticlockwise moments cause positive and negative forces. The right-hand rule is used when solving when the clockwise rotation is used for the person who is standing anti-clockwise. You can use this by putting out your right hand and extending your thumb, middle finger, and pointer finger, all of which should be parallel to one another.

Moment of force is the behavior that happens when a body is subjected to a twisting force. It is quantified as a body’s propensity to rotate about a specific axis. The fundamental idea behind numerous items, including planes, submarines, doors, etc., is the application of force to produce rotation. The opening and closing of a door on a fixed hinge are one of the most common examples of the moment of force in everyday life. Therefore, if you do it every day know that there is a force that is applied. (See What is the Factor that Determines the Inertia of an Object?)