Calculating Moment of a Force: Confused Beginner Asks for Help

In summary, when calculating the moment of a force, you should choose the component that is perpendicular to the radius used as the distance. This means that if the radius is drawn to the 3 o'clock position, the vertical component will produce the torque, while if it is drawn to the 6 o'clock position, the horizontal component will be used. When unsure, the website hyperphysics.phy-astr.gsu.edu can provide more information on basic concepts.
  • #1
shaan_aragorn
43
0
This question may sound silly to all of you brainy guys out there but I am one silly guy.
While calculating the moment of a force how do you choose which component (horizontal or vertical) to choose? I know that M=F*d. Its confusing when authors sometimes use the veritical and sometimes the other component.
Also please let me know if there is a nice little websites where such basic conepts could be found.
 
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  • #2
The component you need is whatever component is perpendicular to the radius you are using as the distance. For example, imagine a circle. If you draw a radius from the center to the 3 o'clock position, then the vertical component will produce the torque. If you draw a radius from the center to the 6 o'clock position, then it would be the horizontal component. The radius dictates the component used.

When in doubt, hyper physics is a great website:
http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html
 
  • #3
inother words you would use the distance that is shortest that makes a rright angle from the line of action to the position of application
 

1. What is the moment of a force?

The moment of a force, also known as torque, is a measurement of the rotational effect of a force. It is calculated by multiplying the magnitude of the force by the perpendicular distance from the pivot point to the line of action of the force.

2. How do I calculate the moment of a force?

To calculate the moment of a force, you need to know the magnitude of the force, the distance from the pivot point, and the angle between the force and the lever arm. The formula for calculating moment is M = F x d x sin(theta), where M is the moment, F is the force, d is the distance, and theta is the angle.

3. What is the difference between moment and torque?

Technically, there is no difference between moment and torque. They both refer to the same concept of rotational force. In physics, the term "moment" is used more often, while "torque" is more commonly used in engineering contexts.

4. Can you provide an example of calculating moment of a force?

Sure, let's say you have a 10 Newton force acting at a distance of 5 meters from a pivot point, at an angle of 30 degrees from the lever arm. To calculate the moment, we would use the formula M = 10 N x 5 m x sin(30) = 25 Nm. This means that the moment of the force is 25 Newton meters, or 25 Joules.

5. How is the moment of a force used in real life?

The concept of moment of a force is used in various real-life applications, such as designing structures, machines, and vehicles. It is also important in understanding and analyzing the movements of objects, such as in sports and everyday activities. For example, the moment of a golf club hitting a ball determines the trajectory and distance of the ball's flight.

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