# Exploring Apparent Forces in Rotating Plates

• nebbione
In summary, the weight force is considered an apparent force in General Relativity, but not in classical mechanics. In classical mechanics, the weight force should be treated as a real force. The Earth is approximately inertial due to its low rotation rate on its own axis, and this deviation is insignificant when compared to the acceleration of gravity. However, for commercial purposes, the centrifugal force resulting from the Earth's rotation must be accounted for when using a spring-based scale to measure weight.

#### nebbione

Is the weight force an apparent force ? Sorry but on the web i can't find anything.
For example if i should think about a man that is on a rotating plate,what are the apparent force ?
I think surely the centrifugal force but should i consider even the wight force of the man ?

nebbione said:
Is the weight force an apparent force ?
In General Relativity it is, in classical mechanics it is not.

For example if i should think about a man that is on a rotating plate,what are the apparent force ?
I think surely the centrifugal force but should i consider even the wight force of the man ?
As this is classical mechanics, you can (and should) treat gravitation as a real force.

Ok thank you very much!
Another question: so when we talk about approximately inertial systems like the earth, the Earth is said to be approximately inertial because it is rotating around the sun right ? and not because we feel the gravity, right =

Last edited:
nebbione said:
Ok thank you very much!
Another question: so when we talk about approximately inertial systems like the earth, the Earth is said to be approximately inertial because it is rotating around the sun right ? and not because we feel the gravity, right =

It is approximately inertial because the rotation rate of the Earth on its own axis is low. The centripetal acceleration associated with the rotation rate of the Earth (at the equator) is approximately 0.03 meters/sec^2.

If you are only quoting the acceleration of gravity to one or two significant figures, this deviation is insignificant.

If you are selling pork barbecue by the pound, this acceleration is significant. In order to be legal for use in commerce, a scale must accurately report the mass of the object being "weighed". Since a spring-based scale responds to apparent weight, this means that the calibration of the spring-based scale must reflect the centrifugal force resulting from the rotation of the Earth on its axis.

Thank you very much! Now i have no doubts!

## 1. What is the purpose of exploring apparent forces in rotating plates?

The purpose of exploring apparent forces in rotating plates is to understand how objects behave when they are in motion on a rotating surface. This can help us better understand the laws of motion and how they apply to real-world situations.

## 2. What are some examples of apparent forces in rotating plates?

Some examples of apparent forces in rotating plates include the Coriolis force, centrifugal force, and Euler force. These forces are not actually present, but appear to be acting on objects due to their motion on a rotating surface.

## 3. How does the Coriolis force affect objects on rotating plates?

The Coriolis force is a result of the rotation of the Earth and causes objects to appear to deflect to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. This force is responsible for many phenomena, such as the rotation of hurricanes and the direction of ocean currents.

## 4. Can apparent forces in rotating plates be seen in everyday life?

Yes, apparent forces in rotating plates can be seen in many everyday situations. For example, when riding a bike, the centrifugal force causes us to lean inwards while turning to maintain balance. Another example is the Foucault pendulum, which demonstrates the Coriolis force.

## 5. How can understanding apparent forces in rotating plates benefit society?

Understanding apparent forces in rotating plates can have practical applications in various fields, such as engineering, meteorology, and oceanography. By understanding how these forces work, we can design more efficient structures, predict weather patterns, and study ocean currents and their effects on marine life.