What is Position: Definition and 1000 Discussions

The missionary position or man-on-top position is a sex position in which, generally, a woman lies on her back and a man lies on top of her while they face each other and engage in vaginal intercourse. The position may also be used for other sexual activity, such as anal sex. It is commonly associated with heterosexual sexual activity, but is also used by same-sex couples.The missionary position is the most common sex position, but is not regarded as the most favoured one. It may involve sexual penetration or non-penetrative sex (for example, intercrural sex), and its penile-vaginal aspect is an example of ventro-ventral (front-to-front) reproductive activity. Variations of the position allow varying degrees of clitoral stimulation, depth of penetration, participation on the part of the woman, and the likelihood and speed of orgasm.
The missionary position is often preferred by couples who enjoy the romantic aspects of ample skin-to-skin contact and opportunities to look into each other's eyes and kiss and caress each other. The position is also believed to be a good position for reproduction. During sexual activity, the missionary position allows the man to control the rhythm and depth of pelvic thrusting. It is also possible for the woman to thrust against him by moving her hips or pushing her feet against the bed, or squeeze him closer with her arms or legs. The position is less suitable for late stages of pregnancy, or when it is desired for the woman to have greater control over rhythm and depth of penetration.

View More On Wikipedia.org
Recent contents Top users
  1. K

    Why does measuring the position of a particle change its momentum?

    Why does measuring the position of a particle change its momentum? Is it because 'measuring' involves shooting EM waves or other particles at the particle, which changes its momentum?
  2. pixartist

    Calculate thrust of a rocket in order to approach and keep a position is space ?

    Okay, first of all, I'm not very good at maths, so I will have to talk in programmer terms here. I have the following issue: A small rocket is moving in space, and I want it to move to and stay at a location in space, similar to a quadcopter. No as far as I see it, I have the following variables...
  3. P

    Why do the constellations appear to move differently in different seasons?

    If the Big Dipper goes around once every 24 hours, why is it in a different position at midnight in December contrasted with midnight in June?
  4. Doofy

    Need to find first postdoc position but lack well-defined 'research interests'?

    I am weeks away from submitting my PhD thesis (hep physics) and would like to carry on as a postdoc. However, I have made no applications so far because the job advertisements stipulate a 'statement of research interests'. This is a problem because I don't really have them. I don't mean that I...
  5. T

    C/C++ How to write C++ code using SGP4 to propagate satellite position

    Greetings all ! I really hope this is the right sub-forum for my question, I have chosen it because I've seen TLE being mentioned a couple of times around here. I have done some reading on astrodynamics and orbital mechanics, but I am relatively new to coding. I would like to write some C++...
  6. F

    Position wave function of two electrons

    Hi, I want to calculate the position-wave-function of a system of two free electrons with momenta k1 and k2 (vectors). 1. Homework Statement So, I want to have Psi_(k1,k2)(x1,x2) for a state |k1,k2> I also know that <k'|k> = (2Pi)^3 Delta(k-k') The Attempt at a Solution I tried the...
  7. C

    The simplest derivation of position operator for momentum space

    Might be simple but I couldn't see. We can easily derive momentum operator for position space by differentiating the plane wave solution. Analogously I want to derive the position operator for momentum space, however I am getting additional minus sign. By replacing $$k=\frac{p}{\hbar}$$ and...
  8. T

    Given acceleration graph, determine v vs. t and x vs. t graph?

    Homework Statement The title, and assume that t=0, x=0 and v=0. Homework Equations Kinematic equations, and area of triangle and rectangle. The Attempt at a Solution I see what I did wrong with the part that is circled "parabola", as it should be just a straight line, but I am lost as to...
  9. HaLAA

    How Does Speed Affect Car Stopping Distance?

    Homework Statement the minimum distance for a car traveling at a speed of 30m/s is 60 m, including the distance traveled during the driver's reaction time of 0.44s. what is the minimum stopping distance for the same car traveling at the speed of 41m/s? v=30m/s, s=60m drivers' reaction time =...
  10. T

    Solving for Position Vector in Arctan: Exploring the Solution Manual's Approach

    Homework Statement 2. The attempt at a solution I would use the arctan (Position j / Position i) and set it equal to the position vector. Then I would substitute values from the graph to find the variables. The solution manual, however, takes the derivative of the position vector and then...
  11. K

    Commutator problem (position, momentum)

    I'm having some difficulties with a certain commutator producing inconsistent results. Specifically I'm referring to [p_x,x^3] Depending on how i expand this it seems i get different coefficients, i.e [p_x,x^3]=[p_x,x]x^2+x^2[p_x,x]=-i\hbar x^2 -x^2i\hbar=-2i\hbar x^2 However...
  12. B

    Equilibrium position of a charge between other 2 charges

    Homework Statement Place a third charge q between two charges Q1 = -2Q and Q2= 3Q so they stay in electrostatic equilibrium. Knowing that the distance between Q1 and Q2 is equal L Homework Equations (KQ1Q)/(QQ1)2 = (KQ2Q)/(QQ2)2 3. The Attempt at a Solution Let's start by saying that i know...
  13. C

    Finding Velocity from Position: How to Use Limits

    Homework Statement The position of a particle moving along the x axis varies in time according to the expression x = 6t2, where x is in meters and t is in seconds. Evaluate its position at the following times. (a) t=2.5s (b) t=2.5s + Δt (c) Evaluate the limit of Δx/Δt as Δt approaches zero to...
  14. A

    Kinematics Acceleration question

    Homework Statement Suppose a can, after an initial kick, moves up along a smooth hill of ice. Make a statement concerning its acceleration. A) It will travel at constant velocity with zero acceleration. B) It will have a constant acceleration up the hill, but a different constant acceleration...
  15. A

    How long will it take cars to overtake?

    Homework Statement A car starts from rest and accelerates uniformly at 3.0 m/s2. A second car starts from rest 6.0 s later at the same point and accelerates uniformly at 5.0 m/s2. How long does it take the second car to overtake the first car? Homework EquationsThe Attempt at a Solution So let...
  16. D

    Natural position of a string wrapping around a cone

    I've had a problem I encountered at work some time ago and took a personal interest in. I never did end up solving it, but I've recently looked at it again. It goes like this: You have an axisymmetric part, such as a cone, and it's positioned such that its central axis is coincident and...
  17. G

    Bohmian determinism for aspects other than position?

    If I got the general idea correctly, Bohmian mechanics is completely deterministic regarding particle positions. But can it also do the same for spin or polarization? How does entanglement work out in it, considering that it should be able to give predictions along any measuring angles, not just...
  18. M

    Position vs Time Lab: Modeling the Relationship for Motorized Cars

    Homework Statement Graphically and mathematically model the relationship between position and the time for a motorized lab car. The definition of position my teacher gave us is: "Where an object is located with respect to a coordinate system. (measured in meters)". Everyone else in my class...
  19. H

    Air resistance, changing position in free fall?

    Let's say that I have a stick with weight evenly distributed throughout. I attach a fan to one end of the stick, then balance it from its new centre of mass. I measure the distance from the ground to the stick then drop it. The stick tilts up towards the side generating more air resistance (fan...
  20. S

    Position of Planets in the Sky | Homework Help

    Homework Statement Indicate the positions of the planets in the sky at the times given. I am struggling on how to answer these questions any help would be great any help would be great. thanks pf! The Attempt at a Solution 1) Jupiter at eastern quadrature around sunset? Jupiter...
  21. B

    Where does that vector come from? What basis is it a representation in?

    Homework Statement Consider the electron on a six site chain. The Hamiltonian is: ## H = \begin{pmatrix} 0 & -1 & 0 & 0 & 0& 0\\ -1 & 0 & -1 & 0 & 0& 0\\ 0 & -1 & 0 & -1 & 0& 0\\ 0 & 0 & -1 & 0 & -1& 0\\ 0 & 0 & 0 & -1 & 0& -1\\ 0 & 0 & 0 & 0 & -1& 0\\...
  22. I

    MHB Graph $r(t)$ for t = $\pi/4$: Position and Tangent Vectors

    $r(t)=sin(t)$i $+ 2cos(t)$j $t= \pi/4$ sketch the position vector and the tangent vector $r'(t)=cos(t)$i $- 2sin(t)$j $r(\pi/4)= \frac{\sqrt{2}}{2}$i $+ \sqrt{2}$j $r'(\pi/4)= \frac{\sqrt{2}}{2}$i $- \sqrt{2}$j $\left\langle \frac{\sqrt{2}}{2}, \sqrt{2} \right\rangle$ $\left\langle...
  23. Philosophaie

    Measuring the current Longitude and Latitude of your current position

    Is there such a electronic device that measures the current Longitude and Latitude of your current position on the Earth?
  24. K

    How Do You Calculate the Position Vector of a Moving Particle?

    A particle P is moving with a const. speed of 6m/s in a direction 2î - j - 2k. When t=0, P is at a point with position vector 3i + 4 j -7k. Find the position vector of P after (1) t seconds (2) 4 seconds. The solutionnstates that ' change the particle speed is constant and is a long text...
  25. P

    Email to professors for research position

    Hello PF! I wish to do research as an undergrad, so I am thinking of sending emails to professors to ask for any available positions. What would be the most professional way to do this? Thanks in advance,
  26. D

    Geometrical optics- position of image

    Homework Statement A sphere of radius 12.0cm has refractive index of 1.33. A speck is 4.0cm from the centre of the sphere is viewed along the diameter that passes thru the speck. Find the position of image when the speck is viewed from the nearer side? the ans is -7.2cm Homework Equations...
  27. Dale

    Position Eigenstates: Measurement & Imperfect Performance

    When a particle's position is measured, does the wavefunction collapse to the eigenstate of the measurement (a delta function), or do you account for the accuracy and precision of the measurement device by making the state be a mixture of eigenstates corresponding to the device's imperfect...
  28. B

    Tenure track position at small University or Postdoc at a top one

    Hi guys!, I am in a kind of dilemma and wanted to know your opinion. I am from a very small european country and came to US for a PhD in a respectable university (top 50 in all world rankings). I just finished my PhD in mathematical modeling of turbulent flows and applied for different...
  29. Z

    Determine particle position knowing the velocity field

    Dear all, I solved the Navier-Stokes equations in Eulerian description. I would like to illustrate it as follows: I thought to place particles in the domain which will characterize the fluid flow. However I must know the particle position in the Lagrangian specification. As I place the...
  30. carllacan

    Matrix elements of position operator in infinite well basis

    Homework Statement Find the eigenfunctions of a particle in a infinite well and express the position operator in the basis of said functions.Homework Equations The Attempt at a Solution Tell me if I'm right so far (the |E> are the eigenkets) X_{ij}= \langle E_i \vert \hat{X} \vert E_j \rangle...
  31. hellsteiger

    Expectation Value of Position for Even Wavefunction

    Homework Statement Hello, I need to calculate the expectation value for position and momentum for a wavefunction that fulfills the following relation: ψ0(-x)=ψ0(x)=ψ*0(x) The wave function is normalised. Homework Equations There is also a second wave equation that is orthogonal...
  32. S

    How do electrons and positrons collide if both have undefined position

    Homework Statement Hi, this isn't a homework question but one that I think has bothered not just me... According to most sources out there an electron and a positron annihilate when they 'collide' or 'encounter' each other, however we also know that the position of an electron or positron...
  33. K

    Ladder operators and the momentum and position commutator

    When using Fourier's trick for determining the allowable energies for stationary states, Griffiths introduces the a+- operators. When factoring the Hamiltonian, the imaginary part is assigned to the momentum operator versus the position operator. Is there a reason for this? If : a-+ = k(ip +...
  34. L

    Planck length and quantized position

    After reading an article on Planck length, I began to wonder whether or not the theoretical limit implied that position could be quantized in whole integer multiples of Planck length? To demonstrate what my question is asking mathematically I hope you will scrutinize the equations below: If...
  35. Q

    Switching the position of matrix elements in Mathematica

    Say I have the following matrix, written in Mathematica A := {{a11, a12, a13, a14}, {a21, a22, a23, a24}, {a31, a32, a33, a34}, {a41, a42, a43, a44}} I want to exchange the positions of a12 and a21, a14 and a23, a32 and a41 , a34 and a43. Any ideas? Thanks.
  36. A

    The multiple derivatives of position

    Hi all, I came across the term placement, and presentment and the likes. I was wondering what they may mean in physics. I tried a search but the answers were not very clear. I was also wondering what action means in physics. Any answers will be appreciated. Thanks
  37. C

    Percentage error of a guess at a position, and the actual position.

    How do I calculate the percentage error between a guess of a position in 3D space, and the actual position. For example, if I am allowed an error of 100mm in the x, y, and z directions, in a 5m x 4m x 3m volume, what is the maximum percentage error allowed? Can I just do...
  38. carllacan

    Position operators and wavefunctions

    Homework Statement Find the eigenfunctions and the eigenvalues of the following Hamiltonian \hat{H} = \frac{1}{2m} \left ( \frac{ \hbar}{i} \vec{\nabla}-\frac{q}{c}(0, B_z x,0) \right ) ^2 = \frac{1}{2m} \left ( - \hbar^2 \vec{\nabla}^2-\frac{\hbar q}{ic}(\vec{\nabla}·(0, B_z\hat{x},0) +...
  39. V

    Homogeneous gravity field time evolution position and momentum operato

    Homework Statement I am trying to solve Problem 21 from this sheet: Homework Equations The equation describing the time evolution of operators is given in the problem. The Attempt at a Solution I have found the commutators of the position and momentum operator with the...
  40. R

    PhD Position in Physics in Germany - Info for Foreigners

    Hello everyone :) I am going to finish my master thesis in physics ( Nano-science ) in Germany at rostock university within the next two months, and i would like to apply for PhD in other city. I am not a German. I would like to ask, whether it is very difficult to get a PhD position in...
  41. S

    Particle Position & Velocity: Solving s=5i+4r^2j

    Homework Statement The position s (in metres) of a particle, as a function of time t (in seconds), is described by the equation s=5i+4r^2j. i and j are perpendicular unit vectors. a) Calculate the position of the particle at t=5. b) Determine the particle's average velocity between t=0 and...
  42. U

    Find the equilibrium position of this piston

    Homework Statement A portion of helium gas in a vertical cylindrical container is in thermodynamic equilibrium with the surroundings. The gas is confined by a movable heavy piston. The piston is slowly elevated a distance H from its equilibrium position and then kept in the elevated position...
  43. J

    Know acceleration as a function of position, can I find velocity?

    Hello I know acceleration of a pendulum as a function of angle. Can I find velocity by integration with respect to theta? My intuition says yes, but dimensional analysis tells me otherwise. What is right and wrong? And what about work? Can I integrate tau = Ia with respect to theta and find...
  44. G

    Unique wave function for a fixed gauge and a velocity and position PDF

    ¿Is there an unique wavefunction for a system if we know the distribution probability function for variables from the system and first derivatives from these variables and we have the gauge fixed (by external impositions not related with the wavefunction knowledge obviously? (Nothing about...
  45. mrspeedybob

    Does uncertainty of position of particles make substances continuous?

    Ever since learning about atoms and molecules as a child I have envisioned substances (air, water, metal, etc) as being composed of discrete individual atoms and molecules. Today it occurred to me that might be an oversimplification, especially for gasses in which molecules are free to move...
  46. jdawg

    Simple harmonic motion derivative of position function

    Homework Statement The function x = (7.4 m) cos[(5πrad/s)t + π/5 rad] gives the simple harmonic motion of a body. At t = 6.2 s, what are the (a) displacement, (b) velocity, (c) acceleration, and (d) phase of the motion? Also, what are the (e) frequency and (f) period of the motion...
  47. J

    Position vector in curvilinear coordinates

    The position vector ##\vec{r}## in cartesian coordinates is: ##\vec{r} = x \hat{x} + y \hat{y}##, in polar coordinates is: ##\vec{r} = r \hat{r}##. But, given a curve s in somewhere of plane, with tangent unit vector ##\hat{t}## and normal unit vector ##\hat{n}## along of s, exist a definition...
  48. nicolauslamsiu

    Equilibrium Position: How Water Affects System

    I want to ask how will the equilibrium position of the system change if water is added to the system?
  49. S

    Advice on obtaining an actuarial position (entry level)

    I'm in the process of job hunting right now and I'm trying to obtain an actuarial position. Looking to hear if any actuaries here have any suggestions or tips on how to increase my chances. Right now, I"m just looking through job searching sites like indeed and monster, and also going to...
  50. S

    Would The Position of the Center of Mass Change Position?

    Take a uniform density bar in space for example. Would the center of mass move if the bar was struck at the very tip perpendicularly by some weight? If so, please explain.
Back
Top