Centrifugal force

Centrifugal force is the apparent outward force of a mass as it rotates. You can think of a ball at the end of a rope that is being turned, or the outward movement you feel when you turn a curve while traveling in a car. In an inertial frame, there is no external acceleration because the system is not spinning. The ball or your body simply moves in the straight line you were originally following. But in the rotating reference frame of the rope or car, they seem to accelerate.

• Unit: Newton
• Symbol: N
• Formula: Fcf= mw²r

What is centrifugal force?

It is a force that appears when describing the movement of a body in a rotating system, or the apparent force perceived by a non-inertial observer located in a rotating reference system.

About centrifugal force

Centrifugal force is the force produced out of a mass when it rotates. Bearing in mind that the Earth rotates around a fixed axis, the direction of the centrifugal force always moves away from the axis, is opposite to the direction of gravity at the equator; and at the poles of the Earth is zero. It is the force needed inwards that prevents the mass from moving in a straight line, it has the same size as the centrifugal force, with the opposite sign. It is important to mention that the centrifugal force is only an apparent force.

How it is calculated

Centrifugal force can be calculated when the exact mass and velocity of the object is known, as well as the radius of the circle in which it is traveling. So the formula for calculating centrifugal acceleration is as follows:

Ac = V² / R

Formula in which:

• Ac: centripetal acceleration
• V= tangential velocity
• R= turning radius

You can also add the following data:

• V= ω R

That is the angular velocity or ω and that is measured in radians / second, which we must multiply by the R, which means radius.

General formula

Fcf= mw²r

Units

Generally, centrifugal force can be measured associated with a moving mass particle (m). For example, in a washing machine a mass particle could be taken as the density of the components of the machine, which are water and clothes.

It can then be measured by the movement velocity which is known as angular velocity and is represented by the letter “w“. On the other hand, evidently a position in the rotation plane (r) that would be the corresponding radius from the center of rotation until where the container in this occasion allows to arrive at the clothes, in the case of the washing machine.

Its general formula is equal to Fcf= mw²r to finally be able to be expressed in the corresponding measure of forces the Newton (N).

Application

The main applications where centrifugal force is used are as follows:

• The inclination in the train curves, because the centrifugal force that drives the train out when it takes the curve, is counteracted by the force that is manifested when the side of the wheels presses on the rails.
• It is used in the centrifuge which is a machine that rotates a sample to accelerate the decanting or sedimentation of its components.
• In centrifugal pumps and turbines that work with liquids and air, respectively.
• In metal casting, due to the precision, safety and quality of the castings.
• In water pumps as they rotate the water around in the turbine so that it is expelled through its corresponding opening carrying the water to the place it is needed.

Importance of centrifugal force

In physical and chemical studies, there is a special method that is used for separating elements, whether liquid or not. This has the purpose of studying its composition through a physical process that is called centrifugation.

The centrifugal force is also in charge of making circular rotary movements through circular energy making that the elements will be attracted towards a center and in this way they can be separated from the other substance.

For this reason, centrifugal force is a very important process that separates and decomposes chemical samples. The results that are made using this process are used for studying the elements applied in the centrifuge. The importance of this method lies in the infinite uses it has in the different areas of physics and chemistry for the separation and union of mixtures.

It is then used in fields such as pharmaceuticals, organic chemistry, basic chemistry, food, nuclear studies and household appliances that need the filtration process.

Examples

Some examples of centrifugal force are as follows:

• Planet rotation: the centrifugal force that occurs in the elliptical rotation that the planets have with respect to their star can be appreciated. An example of this is our planet earth.
• Washing machines: when we put clothes in our washing machine, it is very easy to observe the centrifugal force.
• Blender: when the blender is running you can see the centrifugal force. When we make a fruit milkshake with milk you can see the strength even better.
• When we observe the mud that comes out of a tire or when we see children who feel a force that pulls them out when they play in the carousel.