WHAT IS THE LEVER ARM? - PHYSICAL - 2024

The lever arm is the perpendicular distance from the axis of rotation to the line of force action. The magnitude established for the study of this process is τ = N m. The lever arm is related to the torque present at a particular point.

The distance set by the lever arm functions as a force amplification factor, as can be seen with levers in general.

This relationship ultimately creates a torque and can be graphed by extending a line of force action along with a perpendicular line coming from the point of rotation to create a right angle.

What is a lever?

A lever is defined as a machine whose function is to transfer force and displacement in order to increase the mechanical force, the speed or the distance traveled by a rigid bar.

To express the movement made by a lever, in physics elements such as force (represented by an “F”), power (represented by a “P”) and resistance (represented by an “R”) are taken.

There are three types of lever: first degree, second degree and third degree levers.

First degree lever

The first degree lever is the one where the fulcrum is between resistance and power. The latter may be less than the resistance. A clear example of this type of lever would be the scissors, a rocker or some pliers.

Second degree lever

The first degree lever is the one where the resistance can be located between the fulcrum and the power. In this case, the latter will always be less than the resistance.

A clear example of this type of lever would be the oars of a boat, a nutcracker and even a cart.

3rd degree lever

The first degree lever is the one where the power can be found between the fulcrum and the resistance. A characteristic of this type of levers is that the applied force is much greater than the resultant force.

An example of this type of lever would be a fishing rod, staple removers and even the temporomandibular joint of a person or animal.

How to calculate the lever arm?

The lever arm usually appears frequently when wanting to perform a torque calculation. In order to carry out this procedure, it is first necessary to determine the lever arm and then multiply it by the applied force.

As we said previously, the lever arm is the perpendicular distance present between the axis of rotation and the line of action of force.

The initial equation would be:

Torque on a wrench = Force X Lever arm.

The equation to determine the lever arm is:

Lever arm = r SenѲ.

From then on it is only necessary to clear the lever arm in order to determine its magnitude.

You can also calculate the lever arm in a slightly more general situation and not so much a physical problem.

For this, it is necessary to observe the force applied to the body or object and hence consider the existence of a line perpendicular to the force that is being applied and that is crossing the point of interest that we want to determine.

References

1. Lever Arm. Retrieved on December 16, 2017, from Merriam Webster: merriam-webster.com
2. Lever Arm. Retrieved on December 16, 2017, from Wiktionary: en.wiktionary.org
3. Lever. Retrieved on December 16, 2017, from Wikipedia: en.wikipedia.org
4. Torque and Equilibrium. Retrieved on December 16, 2017, from Hyper Physics: hyperphysics.phy-astr.gsu.edu
5. Torque Retrieved on December 16, 2017, from Wikipedia: en.wikipedia.org
6. Torque Retrieved on December 7, 2017, from Hyper Physics: hyperphysics.phy-astr.gsu.edu