Weight before/after change in rotation Speed

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Homework Help Overview

The discussion revolves around the effect of increased rotation speed on a person's weight at a specific geographic location (48 North and 123 West). Participants explore the implications of a hypothetical scenario where a day lasts only three hours, considering the forces at play in this context.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss the relevance of various forces, including gravitational force, centrifugal force, and potentially the Coriolis force, in determining weight changes due to altered rotation speed. There is an exploration of the balance of forces acting on a stationary person.

Discussion Status

The conversation is actively exploring the relationships between the forces involved. Some participants have provided hints about the need for fictitious forces in a rotating frame, while others are questioning how these forces interact to maintain equilibrium.

Contextual Notes

Participants are considering the implications of working within a rotating reference frame and the necessity of accounting for fictitious forces in their analysis. There is an acknowledgment of the complexity introduced by the change in rotation speed.

Charanjit
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Homework Statement



How would the weight of a person in some place (48 North and 123 West) change if the rotation rate increased so a day was 3 hours long?


Homework Equations



F=ma

The Attempt at a Solution



The above is not the only equation I think that is needed for this. Not sure about this, but coriolis force maybe needed. I just have no clue about this.
 
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Sum of forces on the person = 0 since he's not going anywhere (hint: there are 3 terms in the equation, and yes, it's basically F = ma, except if you're going to derive evbrything you need from that one equation, remember that F and a are vectors, not just scalars).
 
Yes, I understand that F=ma = 0 since the person will not move. Now the three terms that come into play... would the centrifugal force help at all since the Earth is rotating?
 
Yes it would. Since gravitational attrcation is constant, irrespective of rotational speed, what force do you think has to change so the three add up to zero?
 
You are working in a frame fixed to the Earth which is a rotating object hence you are in a rotating frame. Which means that you need to use fictious forces. You need the centrifugal force. The coriolis force is tangent to the Earth's surface... Calculate the component of the centrifugal force normal to the surface of the earth...
 

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