<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I did some research, and it turns out a = v*v/r, where v is the velocity, r is the radius and a is the centripetal acceleration.Earth's radius is about 6378 000 m and the rotational velocity or uniform circular motion at N 28.5 degrees would be 1471 000 m/s. We can assume that the combined center of mass for the individual and the earth resides very very near the center of the earth.Solving this would give us constant centripetal acceleration of 339 m/s2 on latitude equivalent to Florida.Maybe it would better to calculate the force imparted on us by the centripetal acceleration. That would be centripetal force.However, according to wikipedia this should not be confused with centrifugal force, which is a true kinematic force. So now I can't be quite sure what is the net force that is constantly affecting us by Earth's rotation and should be calculated? <br />Posted by aphh</DIV><br /><br /><span class="mw-headline">aphh,</span></p><p><span class="mw-headline"> I think what you need to do in this case is ignore the coriolis force as it is counteracted by friction for somone standing or sitting on the surface of the earth. then solve the equation for centripdal force at the specific latitude in question and then solve for the reactive centrifigal force and subtract the gravitational constant to give a force vector. </span></p><p>**<font size="3">From Wikpedia</font>**</p><p><span class="mw-headline">Rotating sphere</span></p><div class="thumb tright"><div class="thumbinner" style="width:252px">

<img class="thumbimage" src="http://upload.wikimedia.org/wikipedia/commons/thumb/8/8a/Earth_coordinates.PNG/250px-Earth_coordinates.PNG" border="0" alt="Figure 2: Coordinate system at latitude φ with x-axis east, y-axis north and z-axis upward (that is, radially outward from center of sphere)." width="250" height="272" /> <div class="thumbcaption"><div class="magnify">

<img src="http://en.wikipedia.org/skins-1.5/common/images/magnify-clip.png" alt="" width="15" height="11" /></div>Figure 2: Coordinate system at latitude φ with <em>x</em>-axis east, <em>y</em>-axis north and <em>z</em>-axis upward (that is, radially outward from center of sphere).</div></div></div><p>Consider a location with latitude <img class="tex" src="http://upload.wikimedia.org/math/3/5/3/3538eb9c84efdcbd130c4c953781cfdb.png" alt="varphi" /> on a sphere that is rotating around the north-south axis.<sup class="reference">

[1]</sup> A local coordinate system is set up with the <span class="texhtml"><em>x</em></span> axis horizontally due east, the <span class="texhtml"><em>y</em></span> axis horizontally due north and the <span class="texhtml"><em>z</em></span> axis vertically upwards.The rotation vector, velocity of movement and Coriolis acceleration expressed in this local coordinate system (listing components in the order East (<em>e</em>), North (<em>n</em>) and Upward (<em>u</em>)) are:</p><dl><dd><img class="tex" src="http://upload.wikimedia.org/math/b/a/3/ba30cd928bf77f8bb4bedbd9e516d5d4.png" alt="oldsymbol{ Omega} = omega egin{pmatrix} 0 cos varphi sin varphi end{pmatrix} ," /> <img class="tex" src="http://upload.wikimedia.org/math/d/7/0/d706b8d70692ab9cd38985785e0be3f7.png" alt="oldsymbol{ v} = egin{pmatrix} v_e v_n v_u end{pmatrix} ," /> </dd><dd><img class="tex" src="http://upload.wikimedia.org/math/c/6/e/c6e62c86103293ddc86811cb26593c3a.png" alt="oldsymbol{ a}_C =-2oldsymbol{Omega imes v}= 2,omega, egin{pmatrix} v_n sin varphi-v_u cos varphi -v_e sin varphi v_e cosvarphiend{pmatrix} ." /> </dd></dl><p>When considering atmospheric or oceanic dynamics, the vertical velocity is small and the vertical component of the Coriolis acceleration is small compared to gravity. For such cases, only the horizontal (East and North) components matter. The restriction of the above to the horizontal plane is (setting <font style="font-weight:normal;font-size:100%;font-style:italic;font-family:BookAntiqua">v<sub>u</sub></font>=0):</p><dl><dd><img class="tex" src="http://upload.wikimedia.org/math/6/e/c/6ece91a538058dc212db6d0ddaf4ab8d.png" alt=" oldsymbol{ v} = egin{pmatrix} v_e v_nend{pmatrix} ," /> <img class="tex" src="http://upload.wikimedia.org/math/a/5/b/a5b1fe2817cccf01853fe9cb89607b42.png" alt="oldsymbol{ a}_c = egin{pmatrix} v_n -v_eend{pmatrix} f , " /> </dd></dl><p>where <img class="tex" src="http://upload.wikimedia.org/math/5/9/2/592b71cdee7f6e4782afdacc7310be29.png" alt="f = 2 omega sin varphi ," /> is called the <em>

Coriolis parameter</em>.</p><p>By setting <font style="font-weight:normal;font-size:100%;font-style:italic;font-family:BookAntiqua">v<sub>n</sub></font> = 0, it can be seen immediately that (for positive <img class="tex" src="http://upload.wikimedia.org/math/3/5/3/3538eb9c84efdcbd130c4c953781cfdb.png" alt="varphi" /> and <img class="tex" src="http://upload.wikimedia.org/math/a/7/0/a70d0c9b2e529c999ec05569e1638668.png" alt="omega," />) a movement due east results in an acceleration due south. Similarly, setting <font style="font-weight:normal;font-size:100%;font-style:italic;font-family:BookAntiqua">v<sub>e</sub></font> = 0, it is seen that a movement due north results in an acceleration due east — that is, standing on the horizontal plane, looking along the direction of the movement causing the acceleration, the acceleration always is turned 90° to the right. That is:<sup class="reference">

[2]</sup> <sup class="reference">

[3]</sup></p><p> </p><p><span class="mw-headline">Uniformly rotating reference frames</span></p><dl><dd><span class="boilerplate seealso"><em>See also:

Circular motion and

Uniform circular motion</em></span> </dd></dl><p>Rotating reference frames are used in physics, mechanics, or

meteorology whenever they are the most convenient frame to use.</p><p>The laws of physics are the same in all

inertial frames. But a

rotating reference frame is not an inertial frame, so the laws of physics are transformed from the inertial frame to the rotating frame. For example, assuming a <em>constant</em> rotation speed, transformation is achieved by adding to every object two <em>coordinate accelerations</em> that correct for the constant rotation of the coordinate axes. The

vector equations describing these accelerations are:<sup class="reference">

[27]</sup><sup class="reference">

[42]</sup><sup class="reference">

[10]</sup></p><dl><dd><table border="0"><tbody><tr><td><img class="tex" src="http://upload.wikimedia.org/math/b/6/4/b6481b07ca0ef019136bc1a8ab164579.png" alt="mathbf{a}_mathrm{rot}," />