What is Position-time: Definition and 22 Discussions

In computing, position-independent code (PIC) or position-independent executable (PIE) is a body of machine code that, being placed somewhere in the primary memory, executes properly regardless of its absolute address. PIC is commonly used for shared libraries, so that the same library code can be loaded in a location in each program address space where it does not overlap with other memory in use (for example, other shared libraries). PIC was also used on older computer systems that lacked an MMU, so that the operating system could keep applications away from each other even within the single address space of an MMU-less system.
Position-independent code can be executed at any memory address without modification. This differs from absolute code, which must be loaded at a specific location to function correctly, and load-time locatable (LTL) code, in which a linker or program loader modifies a program before execution so it can be run only from a particular memory location. Generating position-independent code is often the default behavior for compilers, but they may place restrictions on the use of some language features, such as disallowing use of absolute addresses (position-independent code has to use relative addressing). Instructions that refer directly to specific memory addresses sometimes execute faster, and replacing them with equivalent relative-addressing instructions may result in slightly slower execution, although modern processors make the difference practically negligible.

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  1. Y

    Acceleration for Position-time graphs

    1. http://www.physicsclassroom.com/Class/1DKin/U1L3a16.gif 2. http://www.physicsclassroom.com/Class/1DKin/U1L3a17.GIF In the first graph, I get that that the slope is negative and that the object is speeding up And in the second graph, the slope is negative and the object is slowing down But...
  2. M

    How to interpret the equation of position with constant acceleration?

    x = x0 + v0 * t + 1/2 * constant acceleration * t^2 So this is supposed to be very very simple physics, but I still feel like there's a part of this equation I don't fully understand. The first term is the initial position of the body at t=0. The second term is the initial velocity at t=0...
  3. Marleycake

    Position-time graph/velocity graph help

    Homework Statement Hi, I just started my kinetics course a few days ago and have a few questions about how to graph this and maybe help me out with some of the equations involved, I'm completely new to this and I got this test sheet a few days ago. thanks a lot guys...
  4. H

    Is -4m the correct displacement for average velocity calculation?

    Homework Statement Calculate the average velocity after 11 s. Homework Equations v=d/t The Attempt at a Solution I need to find the total displacement to find average velocity. I assumed the displacement was -4 as the graph goes up then back down to 0 then -4 so total is just -4. Is that a...
  5. teetar

    How to Find Velocity-Time Graph from Position-Time Graph?

    Homework Statement Not too necessary to follow this format, but here is my question: I know I probably shouldn't ask such a simple question, but how do I find a velocity-time graph from a position-time graph? I know it's just slope, but I'm looking at a curve, and I don't want to differentiate...
  6. S

    Finding acceleration on a position-time graph

    The graph below shows a plot of the position of a particle as a function of time. I need help determining whether the statements concerning the motion of the particle are true or false. The graph: http://imgur.com/yNeHoF3 ? - The instantaneous acceleration at B is zero. True - The...
  7. I

    Position-Time Graph to Velocity-Time Graph

    Homework Statement Hi everybody. I just started grade 11 physics, and I'm having some serious trouble translating P-T graphs to V-T graphs. I really just can't seem to grasp the concept of this. It also doesn't help that I'm doing an online course and we're not being taught anything. The...
  8. J

    Position-time graph made with info from a velocity time graph

    Homework Statement I have been given three velocity-time graphs, and have been asked to use the data from these to create position-time graphs. Each graph represent a route that generally goes south. Changes in direction to go east or west and gradual changes in velocity and time to stop at...
  9. D

    Position-time equation from force-position equation

    I've been trying to obtain an equation of position in terms of time given force in terms of position. I've tried and I think I've managed to obtain an equation of velocity in terms of position using work and kinetic energy but I haven't managed the position time equation. This is how I got...
  10. STEMucator

    Have I Correctly Converted a Velocity-Time Graph to a Position-Time Graph?

    Homework Statement Using the velocity time graph, create a position time graph and record the total distance traveled. V-T Graph : http://gyazo.com/672bd621cbd9f7ab9dcba1250268ee7e Homework Equations Since we have constant velocities for certain time intervals we need to use ##Δd =...
  11. T

    Simple position-time function question

    Homework Statement A stone falls freely down a well. 1.6 seconds later, another stone is cast 25m/s in a straight line, down the well. The two stones hit the bottom of the well at exactly the same time. How deep is the well? ag=9.8 m/s2 Homework Equations x=x0+v0+1/2at2 The Attempt...
  12. S

    Position-time graphs and tangent lines

    The Following data table provides information about a crate of radishes that is sliding down the ramp of a delivery truck time position 0 ------ 0 2------ 0.6 4-------2.4 6------- 5.4 8------- 9.6 10------ 15Next it asks you to draw a position time graph, which i did, and its identical...
  13. B

    Position-Time graph vs. Velocity-Time graph

    The page layout is included in the picture attachments which are in order. So far, if I'm correct, the constant velocity between position- 0 and time- 8.2 is 1.5m/s The part I'm having trouble with is the curves of the line (how to figure them out and how to place them on the velocity-time...
  14. D

    How to draw a position-time graph from a velocity-time graph?

    And vice-versa? I'm having quite a hard time at doing this. Any tips? My book isn't exactly "layman" friendly. Thanks so much for all the help, I appreciate it. :smile:
  15. X

    Average velocity from a position-time graph?

    what is the object's average velocity during the entire interval? ..i know velocity would be the slope..but there's different slopes so what do i do? does it have to do with instantaneous velocity?! physics makes me sad. :(
  16. U

    Help finding slope on position-time graph

    Im trying to make fill in a velocity-time graph from the a picture of a position-time graph. The position-time graph starts at 20m (no direction indicated) and slides dowb to 5m in 4 seconds. The slope would be -4m/s right? But the V-T graph I have to fill in has a maximum velocity of 6 m/s and...
  17. C

    Ridiculus position-time graph extrapolation

    I'm working on some physics lab homework and one particular graph is obnoxious. It's hard to tell whether it's intended as a compound curve, or if it's just a piss-poor sketch. I've contacted my professor but he hasn't responded for days, and it's due tomorrow. If I'm not mistaken, the...
  18. L

    Investigating Particle's Acceleration from Position-Time Graph

    Homework Statement The figure below depicts the motion of a particle moving along an x-axis with a constant acceleration. What are the magnitude and direction of the particle's acceleration? Can anyone explain to me where to begin on this one? It's a graph of position of time. It's...
  19. Nabeshin

    Constructing a Position-Time Function for a Rocket

    Suppose that I want to launch a rocket and want to construct a position-time function for the rocket so that I know where it will be at any given time t. To make this realistic, say mass varies with time, so as the rocket burns fuel it becomes lighter. Suppose the rocket, burning fuel at a...
  20. H

    Two objects, position-time graph

    Homework Statement At t = 0, two objects are thrown from a vertical tower of height H (in m) with an initial speed of v initial (in m/s) in opposite directions (one upwards and one downwards) so that the objects fall to the ground at the base of tower. Ignore the effects of air resistance...
  21. I

    How do you find average velocity from a position-time graph?

    Also, how do you find instantaneous velocity from a position-time graph?
  22. J

    Motion and Position-Time Graphs

    A police officer clocked a driver going 20 mph over the speed limit just as the driver passed a slower car. He arrested both drivers. The judge agreed that both were guilty, saying, "If the two cars were next to each other, they must have been going the same speed." Are the judge and police...
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