Centripetal combined with Gravitational Force

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Discussion Overview

The discussion centers on the relationship between gravitational force and centrifugal force due to the Earth's rotation, specifically whether the latter affects the acceleration due to gravity, commonly approximated as 9.8 m/s². The scope includes conceptual understanding and the implications of Earth's shape and rotation on gravitational measurements.

Discussion Character

  • Conceptual clarification, Debate/contested

Main Points Raised

  • One participant calculates the acceleration due to gravity as 9.8 m/s² and questions the impact of centrifugal force from Earth's rotation on this value.
  • Another participant asserts that the Earth's non-spherical shape is a consequence of centrifugal force, suggesting a connection to the discussion.
  • A later reply indicates that the apparent effect of gravity for someone on the rotating Earth differs from the theoretical value, noting that local variations can lead to different measurements of g.
  • There is mention of a historical value of 9.82 m/s² taught in high school, implying that educational contexts may present variations in the understanding of gravitational acceleration.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between centrifugal force and gravitational acceleration, with no consensus reached on how significantly centrifugal force affects the measured value of gravity.

Contextual Notes

The discussion highlights the dependence on location for gravitational measurements and the potential for variations in the value of g, but does not resolve the implications of these factors on the understanding of gravitational force.

dliangsta
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Hi! So I learned Newtons Law of Gravity and used the numbers to calculate that the acceleration due to the attraction between masses is 9.8m/s/s. Hooray! This is what I've learned is the acceleration due to gravity. However, does the rotation of the Earth and the subsequent centrifugal force play any role in decreasing the strength of gravitational force? I naturally think that it would but what I've learned doesn't reflect this. Thanks :)
 
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Yes. This is why the Earth is not a perfect sphere (modulo local variations such as mountain ranges).
 
Orodruin said:
Yes. This is why the Earth is not a perfect sphere (modulo local variations such as mountain ranges).
Thanks again @Orodruin ! So then, does the 9.8m/s/s decrease because of the centrifugal force?
 
This depends on what you refer to. For someone rotating with the Earth, this will be the apparent effect. The measured value of g does differ from location to location (although 9.8 m/s^2 is the best approximation with two significant digits everywhere). When I was in high school, the value we were taught was 9.82 m/s^2, because it is what it is here. See also http://en.wikipedia.org/wiki/Gravity_of_Earth
 

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