Southerly Deflection by Motion of the Earth

In summary, Marion and Thornton discuss the calculation of horizontal and southerly deflections from the plumb line of a particle falling in Earth's gravitational field. They use the zeroth order result for the time-of-fall and perform a calculation in second approximation, taking into account three components: the Coriolis force to second order (C1), the variation of centrifugal force with height (C2), and the variation of gravitational force with height (C3). Each component yields a result of C_i(h^2/g)w^2 sin(lambda) cos(lambda), with C1=2/3, C2=5/6, and C3=5/2. The authors also provide relevant equations and discuss the
  • #1
bob1182006
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Marion and Thornton Classical Dynamics of Particles and Systems 5th ed. Chapter 11 #13.

Homework Statement


(Refers to an example where they calculated the horizontal deflection from the plumb line of a particle falling in Earth's gravitational field).
Take g to be defined at ground level and use the zeroth order result for the time-of-fall, [itex]T=\sqrt{2h/g}[/itex]. Perform a calculation in second approximation (retain terms in [itex]w^2[/itex]) and calculate the southerly deflection.
There are three components to consider (a) Coriolis force to second order (C1), (b)variation of centrifulgal force with height (C2), (c) variation of gravitational force with height (C3).

Each component gives a result:
[tex]C_i\frac{h^2}{g}\omega^2sin(\lambda)cos(\lambda)[/tex]
with C1=2/3, C2=5/6, C3=5/2.


Homework Equations


[tex]\vec{F}=\vec{S}+m(\vec{g_o}-\vec{\omega}\times(\vec{\omega}\times\vec{r}))-2m\vec{\omega}\times\vec{v_r}[/tex]
[tex]\vec{g_o}=-G\frac{M_e}{(R_e+h)^2}[/tex]

The Attempt at a Solution


The coordinate system has z radially outward from the Earth. x in the southerly direction, y in the easterly direction.
[itex]\lambda[/itex] is the latitude.
[itex]\vec{S}=0[/itex], Assuming no external forces like air resistance.

[tex]\vec{\omega}=-\omega cos\lambda\vec{e_x}+\omega sin\lambda\vec{e_z}[/tex]
[itex]R_e[/itex]+h is in the positive z direction
[tex]\vec{\omega}\times(\vec{R_e}+\vec{h}})=(R_e+h)\omega cos\lambda \vec{e_y}[/tex]
[tex]\vec{\omega}\times(\vec{\omega}\times(\vec{R_e}+\vec{h}))=-\omega^2(R_e+h)sin\lambda cos\lambda \vec{e_x}-\omega^2(R_e+h)cos^2\lambda \vec{e_z}[/tex]

For [itex]v_r[/itex] I think it should be just -gt in the radial direction. But my book says that the Coriolis Force produces a small velocity component in the y and z directions that they neglected.
Would the component of the velocity of the z direction be [itex]-g_ot-t\omega^2(R_e+h)cos^2\lambda[/itex]? Or is it just -gt?
 
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  • #2
I believe your problem asks for only terms up to [tex]\omega^2[/tex]. So you can treat the velocity as -gt in the z-direction. But you might want to check this.
 

Related to Southerly Deflection by Motion of the Earth

1. How does the motion of the Earth cause southerly deflection?

The Earth's rotation on its axis and its orbit around the Sun cause the Coriolis effect, which results in southerly deflection of moving objects in the Northern Hemisphere and northerly deflection in the Southern Hemisphere.

2. What is the Coriolis effect?

The Coriolis effect is an inertial force that occurs due to the Earth's rotation. It causes objects in motion on the Earth's surface to appear to deflect to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

3. How does southerly deflection affect weather patterns?

Southerly deflection plays a significant role in the formation and movement of weather patterns. In the Northern Hemisphere, it causes winds to curve to the right, which helps to create high and low-pressure systems and influences the direction of storm systems.

4. Does southerly deflection have any impact on ocean currents?

Yes, southerly deflection also affects ocean currents. In the Northern Hemisphere, the Coriolis effect causes ocean currents to move clockwise, while in the Southern Hemisphere, they move counterclockwise.

5. How does southerly deflection impact navigation and transportation?

Southerly deflection can impact navigation and transportation routes, especially for air and sea travel. Pilots and ship captains must take into account the Coriolis effect when planning routes to avoid any potential disruptions caused by southerly deflection.

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