Displacement Definition and 999 Threads

  1. N

    An ornament for a courtyard at a World's Fair is to be made up of four large metal spheres

    After applying a small displacement along the axis between the center of the bottom ball and the projected center of the fourth ball, I got 4 as the answer, which is twice the correct value. I’m assuming I didn’t account for the fact that the tension force acts on both sides, so I ended up...
  2. S

    Calculating the sum of displacement vectors

    I greet everyone I am faced with such a question First 100m to the right, then 300m down, then 150 left diagonally, even I don't think this is exactly right, I think there will be 150x sin30 or cos30, but I'm not sure, I need to do 200xcos60 afterwards, but I couldn't settle the question. can...
  3. B

    Textbook 'The Physics of Waves': Calculating Work Done by Force

    Reference textbook “The Physics of Waves” in MIT website: https://ocw.mit.edu/courses/8-03sc-...es-fall-2016/resources/mit8_03scf16_textbook/ Chapter 2 - Section 2.3.1 [Page 45] (see attached file) Question: In the content, it states that we need to use real force and real displacement...
  4. A

    I Instantaneous velocity - displacement and distance

    Instantaneous velocity is defined as the first derivative of displacement with respect to time: ##\vec{v} = \dfrac{d \vec{r}}{dt}## However, instantaneous velocity is also defined as the first derivative of function of distance with respect to time: ##v = \dfrac{ds}{dt}## Why do these two...
  5. hamishmidd

    Finding a formula for displacement of a mass on a spring using v.

    I have tried to answer this using the relevant equations I am provided on my formula sheet, however I get stuck pretty close to the end. I start with 1/2mv^2=1/2kx^2 at the equilibrium position, and kx=mg, x=mg/k. This gets me to v^2=mg^2/k, but I don't know where to go from there. The potential...
  6. G

    I Does displacement current create a magnetic field? And Lorentz force?

    Hi. Does displacement current create a magnetic field by Biot-Savart? I googled and found contradictory answers. Also, in the presence of an external magnetic field, is it meaningful to calculate a Lorentz force acting on displacement current? What does the force actually act on then?
  7. hello478

    Vertical displacement with time of a projectile

    my answer was D, which is correct considering the motion downwards eg, object thrown from a cliff but what if an object is moving up?like a football being kicked? i cant understand how this graph applies to that...
  8. chwala

    Find in terms of ##h## when ##P## comes instantaneously to rest

    I need insight on the highlighted part; Total height ##= 2h + h + H## In my understanding, the displacement on either side would be the same, that is ##=h##m given the condition (assumption) that ##a=0##.
  9. waadles

    I Displacement operation acting on individual quadrature components

    Hi all, I have a naive understanding of how operators work and wondered if someone could help me. I have tried to understand this myself, but alas, I think my knowledge is too premature to understand what I am reading online. Is someone able to explain? I want to perform the operation...
  10. Ineedhelpwithphysics

    'Police Car Catching Up' problem in kinematics

    Why is it 10.92 seconds and not 10 Cars displacement = 30*t +1/2(0)t^2 police displacement = 0*t + 1/2(6)(t)^2 30t = 3t^2 t = 10 seconds ???
  11. brotherbobby

    B Kinematic equations ##\textbf{purely}## from graphs

    1. The first equation between velocity ##v## and time ##t## can be derived using the graph I have drawn for the purpose as shown on the right. Since acceleration ##a_0## is a constant, the graph of ##v-t## is a straight line. The slope of the line is ##\dfrac{v-v_0}{t} = a_0\Rightarrow \boxed{v...
  12. N

    I Calculating phase shift between two sinusoidal waves

    Hello, Came across this picture and passage from a textbook. Although the text lays out a method for calculating the phase shift between displacement and acceleration, I am not sure how they are calculating which wave is leading and which is lagging. From their description, it seems like a...
  13. Remle

    Doubt Calculating the Total Displacement for this Person Walking

    I having a little bit of problem with ##\Delta d = d_f - d_i##. When substituting fo ##d_f## and ##d_i##, should I follow the signs rule (positive or negative)? For example, The problem shows that the displacement is ##1.2~\rm{km}, south## by solving ##\Delta d = -2.5 + 1.3## and I get that, but...
  14. C

    Needs clarity on this displacement vector diagram

    The problem is actually a solved example My attention is focused in understanding the displacement vector diagram as it has to deal with question (iv). I have no problem understanding the velocity vector sketch below: As you can see ND is the velocity of the river current due East and NE is...
  15. Slimy0233

    I Force on Body Attached to Spring at Displacement x - A.P. French

    Source: A.P. French's Vibrations and Waves I do not recognize the first equation, can someone explain how it came to be? The reasoning behind it. How can force on a body attached to a spring at small displacement x be represented as ? I know recognize F = - kx (restoring force) I realize...
  16. enigmaticbacon

    How many capybaras does it take to move a Stonehenge rock?

    I’m writing a presentation for younger students explaining how science can help them satiate their curiosity in a fun way. This presentation’s goal is to apply as much science as possible to a ridiculous question in hopes of promoting STEM fields. My example is, how many capybaras --the world’s...
  17. G

    Understanding Negative Velocity and Displacement on a Velocity-Time Graph

    I think the area required is a displacement.
  18. O

    Analyzing Motion: Deriving Displacement Graphs from First Principles

    Initial displacement is h above the ground ie ##s\left ( t =0\right )=h##. I've chosen the ground as the vertical origin with upwards as the positive direction. Gravity will therefore always act in negative direction throughout. Here are the graphs I which to reproduce from first principles...
  19. Lotto

    What is the smallest value of angular displacement of the raft?

    What is meant by "the smallest value of angular displacement of the raft from its original position during one cycle"? I understand that I am supposed to solve this problem using torques of the crane and and of the boxes, but I am totally confused by that "smallest angular displacement". If it...
  20. E

    B Displacement of Hanging Mass - Simple Pulley System

    I'm having some kind of mental block. If I extend ##l_x## by ##\delta## ,I expect the hanging mass to move ##\frac{ \delta}{2}##. I can't figure out how this is the case from the constraint: $$ l_x+l_1=C $$ ##C## is an arbitrary length I keep getting that ##l_1## changes by ##\delta##, but...
  21. A

    Integrating motion equation to derive displacement

    ##\frac{dx}{dt} = \frac{dx_i}{dt} + \frac{d^2x}{dt^2}t## Multiplying dt on both sides and integrating we have ##\int_{x_f}^{x_i} dx = \int_{0}^{v_i t} dx_i + \int_{0}^{at} dvt## so ##x_f - x_i = v_it + at^2##, which is not right Where did I go wrong? I understand that if we substitute a for...
  22. chwala

    Solve the problem that involves vector displacement

    My interest is on part ##a## only. Is the markscheme correct? I have ##BA= -b+a= a-b.## It therefore follows that ##|a-b|## is the Length of ##BA##...or are we saying it does not matter even if we have ... ##AB.## Cheers
  23. S

    B Calculation of displacement of an object

    Hi, this is my first time here. I'm and E&E student currently working on a project. I'm trying to calculate the overall displacement of my device given the X and Y displacement of the object and also the yaw heading of the device. The direction of the heading is the direction where the X axis...
  24. S

    Why not use positive displacement turbines?

    Positive displacement pumps are used a lot in the industry for pumping water or other liquids. So why is it not used as turbines in hydropower plants?
  25. B

    Question on the Newtonian displacement of light

    Hi everyone! Hope your day is going well. I’m an ex-physics student who recently wanted to go back to studying the subject (as a hobby, mostly). So I picked up Zee’s GR book since GR is the thing I’m the most interested in. I expected to hit a wall on some basic things since I’m rusty, and did...
  26. M

    Why do I have a bending moment and an axial displacement here?

    Hello, I have an flexure where the force is applied asymmetrical, I just can't visualize why their should be a bending moment instead of an bending force? How can I distinguish those? Thanks!
  27. R

    Displacement Electric Field Outside Dielectric Material

    I know that inside region 1, the D-field is zero as it is a conducting sphere, the E-field must be zero. It makes sense that in region 2 (inside the dielectric) there is a D-field. My question is, is there a D-field outside the dielectric material (r>R)? Obviously there will be an E-field, but...
  28. Stewkatt

    Motion of an Object: Displacement & Average Velocity

    An object starts from rest and accelerates at 3.0 m/s2 for 4.0 s. Its velocity remains constant for 7.0 s, and it finally comes to rest with uniform deceleration after another 5.0 s. Find the following: a. the displacement for each stage of the motion b. the average velocity over the whole time...
  29. rudransh verma

    Integration of velocity to get displacement

    Integration of v= integration of##(alpha \sqrt x)dx##. But I am getting wrong answer.
  30. rudransh verma

    Why do we use area under the curve to find displacement in particle motion?

    I calculated v=0 at t=3. s(3) =24 m. s(5)=16 m. So reverse distance that the particle travelled=24-16=8 m. So total distance =24+8=32 m.
  31. B

    B Does gas expanding in a container cause displacement of the container?

    If particles are trapped in one half of a massless container by a barrier, and the barrier is removed so that the particles are allowed to expand to fill the whole container, it seems the center of mass would be displaced to the center of the container, whereas before it was located at the...
  32. U

    COMSOL: Why does the prescribed displacement stop at a certain point?

    I have been experimenting in producing some strain to this object. However, after applying a prescribed displacement and setting it to a certain value, it does not exceed 2.18[um] no matter any extreme value for the prescribed displacement. I have also experimented with an applied force as well...
  33. kara123

    Determining displacement and acceleration: A physics problem

    -began by finding Fnet=Fg-Ff =1176-270.48 =905.52 acceleration = 905.52/120 kg =7.546 m/s2 sub numbers into vf2=vi2+2aavd -got an answer of -5.6m so clearly it,s wrong because displacement...
  34. L

    What is the maximum spring displacement?

    the mass will drop 1 m before it comes in contact with the spring. I’m stuck afterward. Please help. The total energy of 1 m is mgh= 1kgx9.8m/ss x 1m = 9.8J 9.8J = .5 x 20N/m x x^2 ---> x = .99 m the spring is compressed by .99 m ?
  35. rudransh verma

    Projectile negative vertical displacement

    I know how it’s done. So let’s jump on the question. The displacement that came was negative 6 cm. I want to know how this formula describes perfectly negative displacements. I don’t understand the mechanism. If I assume ##ut## to be distance traveled in absence of g then what is ##-1/2gt^2##...
  36. Tutor 9640

    Is there a forum for NYC physics standards K-12?

    I am a new tutor working with students in 11th grade physics in New York City. I am required to keep notes internally on the sessions and the standards that I cover in them; after noticing that the physical science standards don’t include mentions of velocity or displacement as a content area, I...
  37. U

    Displacement problem with unit vectors

    (a) I did (7.07*4.1)-(-7.03*3.94)=56.7 with this method I got this answer correct in my first attempt. (b) This where I seem to have gone wrong. I used a · b = (axbx +ayby) then I used a = sqrt(ax2+ay2) to get a single number for the answer. Filling in the numbers 7.07*-7.03 + 4.94*4.1 =...
  38. vel

    Displacement nodes for overtones

    (4 / 3) * (1.8) = 2.4 = lambda 1st overtone: 2.4 / 4 = .6; (2.4 * 3) / 4 = 1.8
  39. Paul Chen

    Screw dislocation displacement discontinouty

    Consider a screw dislocation, The displacement field is given by And the strain field is derived by My question is that the displacement seems discontinuous across the dislocation surface (y=0, i.e., displacement jump from 0 to b), so why it is still differentiable on the surface and why...
  40. K

    I Virtual displacement is not consistent with constraints

    Goldstein 3rd ed says "First consider holonomic constraints. When we derive Lagrange's equation from either Hamilton's or D'Alembert's principle, the holonomic constraint appear in the last step when the variations in the ##q_i## were considered independent of each other. However, the virtual...
  41. FEAnalyst

    Hertz contact stress with prescribed displacement

    Hi, one can easily find formulas for Hertz contact stress in various cases (two spheres, two cylinders and so on) when force is applied to one of the bodies. But how to get the equivalents of those formulas when prescribed displacement is used instead of stress ? For example, I’ve found this...
  42. K

    Virtual displacement for a block sliding down a wedge

    A block slides on a frictionless wedge which rests on a smooth horizontal plane. There are two constraints in this system. One that the wedge can only move horizontally and another that the block must remain in contact with the wedge. We want to find the virtual displacements for the two block...
  43. C

    I Help please -- Trying to figure out rake barge capacity and displacement

    Barge size is 54.864 x 15.5448 x 2.95 m and Barge capacity 1500 ton Sorry to misunderstand. I am learning. Not to disturb others. My load is 350 Ton size above shown. What the draft after load the cargo on the barge? The barge draft 470mm Bow side after 5m has slope. I mean front side from the...
  44. D

    I Schrodinger Cat states in terms of Displacement Operator

    The coherent state can be written in terms of e^(αb†+α∗b)|0>. But how the even coherent state i.e. |α>+|-α> can be written in terms of displacement operator?
  45. D

    I Commutation of Beam splitter operator with Displacement operator

    I have a beam splitter operator (a†)b +(b†)a. Does it commute with exp(αâ†-α*â). Here a and ↠are creation and lowering operator
  46. akashpandey

    I Why is the definition of work = force times displacement?

    Hello everyone, I was curious about how do we define a physical quantity and mathematical relation between them. For example: Work done is defined as product of force along the displacement and displacement i.e W=Fcos(theta)d. Now this definition is given in books straightforward but my...
  47. A

    SR - Getting Zero Spatial Displacement

    Summary:: I have tried for some time to understand my error but can't figure it out. Any help will be much appreciated. Hi! I'm trying to figure out why the spatial displacement from two events A and B gives zero when I use one method compared to another which doesn't give zero spatial...
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