Magnitude Definition and 1000 Threads

  1. M

    Change in apparent magnitude of a star after exploding

    Finding the apparent magnitude before the explosion is straightforward and easy.$$m= M + 5log(\dfrac {d}{10}) = 29.19$$ Idk how to find it after explosion ... The change in apparent magnitude should be calculated using ##-2.5log(10^9)## , Idk why this formula is true and where it came from ...
  2. billtodd

    Engineering How Can I Find the H-infinity Norm of a Transfer Function?

    I want to find ##\|G\|_\infty##, the solution in the pic uses the Bode plot. But to tell you the truth I am worse at drawing it. So basically what I thought is I want to find: ##|G(i\omega)|=1/\sqrt{(25−\omega^2)^2+9\omega^2}##. So basically I much prefer to find the minimum value of what is in...
  3. J

    I Units of a vector in a velocity vs time graph?

    This post parallels a post I made in electrical engineering regarding the S plane. I thought I would post an equivalent in basic physics. So, given a graph of velocity vs time we have on the vertical axis meters/sec and the hormonal axis just meters. Given a plot of V vs t we know the area...
  4. J

    Units for a vector magnitude in the s-plane

    In the S plane we have a real component, usually called sigma, and the imaginary component, jw, in radians/sec. The real component is sometimes called nepers per second, with nepers being dimensionless. However, if we draw a vector in the s-plane, say s - s1, in polar form, what are the units...
  5. chwala

    Find the magnitude of the child's acceleration

    In my working i have; For a) ##\tan 55^{\circ} = \dfrac{450}{R}## ##R = \dfrac{450}{\tan 55^{\circ} }= 315 N## part b) no problem here ...horizontal to left. c) This is where my real doubt is, i have using sine rule; ##\dfrac{9.8}{sin 55^{\circ} }= \dfrac{a}{sin 35^{\circ}}## ##a =...
  6. chwala

    Find the direction and the magnitude of Frictional force

    In my working i have, the attached. My question is Why is the Reaction force not being considered here, My equations are; Frictional force = ## 30\cos 50^0 - 20\cos 40^0 = (19.28 - 15.32)N = 3.96N## The direction will be downwards.
  7. chwala

    Find the magnitude and the direction of the resultant vector

    Going through this ( Revision) A salways your insights are quite helpful. I would like to go through all these questions; i will start with (5), ##\left( \dfrac {x} {y} \right)## = ##\left( \dfrac {10 \cos 40^0} {10 \sin 40^0} \right)## + ##\left( \dfrac {4 \cos 150^0} {4\sin 150^0}...
  8. chwala

    Calculate the magnitude of driving force on the car

    My approach is as follows, let ##D## be driving force and ##F## the force resisting motion, then ##D-F = 850 × 0.3## ##D = 250 + 255## ##D = 505## Also, Force parallel to the road is given by, ##F_1 = 8500 \cos 78^0 =1767.24 N## Therefore, the magnitude of Driving force is given by, ##F_1 +...
  9. W

    Difficult Understanding Magnitude and Phase Shift of Transfer Function

    Hello, My textbook offers the following transfer function as an example. It then goes on to explain that the following equations represent the magnitude and phase shift of the transfer function. However, I am having some difficulty jumping from the first equation to these equations. From...
  10. Astronuc

    Mag 2.7 earthquake in Cornwall, 19 Nov 2023

    Cornwall shaken by 2.7 magnitude earthquake https://www.bbc.com/news/articles/c724le759lro That's not a significant earthquake, unless one's house is near the epicenter. Residents in Helston, Penzance and Camborne reported feeling the tremors. Some of my ancestors were from that area, and I...
  11. Astronuc

    Rare 5.3 Mag earthquake jolts West Texas

    https://www.msn.com/en-us/weather/topstories/rare-5-3-magnitude-earthquake-jolts-west-texas/ar-AA1jBhJ8 M 5.2 - Coalson Draw, Texas https://earthquake.usgs.gov/earthquakes/eventpage/tx2023vxae/executive 2023-11-08 10:27:49 (UTC) 31.622°N 103.982°W 7.4 km depth There was an unusal set of...
  12. Ineedhelpwithphysics

    Finding the magnitude (length) and direction (angle) of a vector

    So i found the magnitude which is (-1)^2 + (-2)^2 = P^2 = Sqrt(5) Then I used the inverse tan function to find the angle (direction) theta = arctan (-2/-1) = 63.8 degrees Im confused with my 63.8 degrees since the angle in the graph looks greater than 63.4 degrees I subtracted 180 by 63.8 and...
  13. E

    Vector is a function of its position or not?

    At first I thought that this force vector ## \vec F = 3 \hat x + 2 \hat y ## is a function of ## x ## and ## y ##, which is to say that its magnitude and direction vary with the x and y positions, but this is not so, right? It's just a force with a constant magnitude and direction. And I can...
  14. paulimerci

    What is the magnitude of the field at point R?

    I've no idea how to solve this problem. The sign of the charge is not mentioned, so I'm assuming the charge is "+". The charge exerts an outward electric field. Since two lengths of the right-angle triangle are given, I use the Pythagorean to find the hypotenuse, which is the distance between q...
  15. paulimerci

    Find the magnitude of the electric field at point P

    There are two identical spheres with the same charge that are the vertices of an equilateral triangle. ##+3 \mu C## will exert an outward electric field, which is drawn in the FBD below (see the attached pic), Since the horizontal force components (1x and 2x) are equal and opposite at point P...
  16. paulimerci

    Find the magnitude of the electric force from 3 charges at vertices of a cube

    There are three charges with +1 μC and −1 μC, are placed at the opposite corners of a cube with edges of length 1 cm, and the distance from P to B is 1cm 2. I labeled them as A, P, and B, which is shown in the diagram below. Since we need to find the magnitude of the charge at point P and the...
  17. T

    I Understanding Vectors: Magnitude & Direction

    Good Morning (And apologies if this is not the right forum -- it is not a homework problem.) On the one hand, a vector is an arrow and a tail: it has magnitude and direction. It is used to describe direction, forces, acceleration, etc. However, there are more mathematical definitions: a...
  18. K

    A Confused about magnitude of error

    Hello! I am trying to simulate the following experiment. It is a counting experiment where the probability of getting an event after a given trial is given by: $$P = 2\left(\frac{a}{x}+\frac{b}{c}\right)^2\left(1-\cos\left(\frac{\pi x}{x_0}\right)\right)$$ where, ##a = 4\pi##, ##b = 2000\pi##...
  19. M

    Vector Calculus in 1D: ± to Show Magnitude?

    [mentor's note - moved from one of the homework help forums] Homework Statement:: It's a question. Relevant Equations:: Vector calculus. Is it true to say that in one dimension I can show vector quantities using ±number instead of a vector? ± can show possible directions in one dimension and...
  20. sHatDowN

    Vector problem, magnitude of the force

    Member CB of the vise shown exerts on block B a force P directed along line CB. Knowing that P must have a (1237) N horizontal component, determine (a) the magnitude of the force P, (b) its vertical component i don't get it what the "N horizontal component"
  21. F

    Magnitude of the Line Charge Density of a Power Line

    Okay so I am a little confused as to where I made a mistake. I couldn't figure out how to program Latex into this website but I attached a file with the work I did and an explanation of my thought process along the way.
  22. paulimerci

    Find the magnitude of the momentum change of the ball?

    I understand that it is a 2D momentum problem with an elastic collision; Looking at the vector diagrams below, I notice that the velocity vectors initial and final in the y direction are in the same direction, indicating that momentum does not change, whereas the velocity vectors initial and...
  23. baumbad

    Given a Constant Acceleration magnitude of g/4, Find the value of t

    I got to the quadratic equation of the motion where: 4gt^(2) - g(delta t)t - g(delta t) = 0 and tried to solve for t. In this case, we would take the positive discriminate since we are dealing with the passing of time. t = ((sqrt(17) g(delta t)) + g (delta t)) / (8g) However, this is the...
  24. M

    Magnitude of external electric force on electric dipole

    For this part(b) of this problem, how is the magnitude of the total electric force zero? I thought it would be: If they asked for the total electric force, then I would have said zero because the two electric force vectors cancel. Many thanks!
  25. maxolina

    Order of Magnitude Difference: Solving with Torricelli & Bernoulli

    Solving with Torricelli I get Vt = 6x10^-3 m/s Solving with Bernoulli I get Vt = 6x10^-4 m/s, a whole order of magnitude smaller. How can it be correct? I know that Torricelli is an approximation, but the solution given by the book uses Torricelli which doesn't seem right to me.
  26. Harikesh_33

    I Question regarding finding the magnitude of Torque

    Question regarding finding the magnitude of Torque of a system of two masses attached to a rod rotating at angle of θ degrees with respect to a vertical
  27. correction_tape

    Finding the Magnitude of the Force Acting on an Object

    So far, I've only attempted the first number: F = (4kg) [(-4+2t)-0]/t ? Been thinking how to cancel out the time, but I really have no idea how to proceed. Was I supposed to cancel it even? Can someone please help and tell me how you would answer this? (And maybe show a solution as well so I...
  28. Svelte1

    Solving for Speed: Exploring Velocity and Magnitude

    https://ibb.co/jG6n0jZ The 15 is fine as this is clearly his overall magnitude but then v2 is equated to the horizontal velocity rather than the magnitude.
  29. gmax137

    7.3 Magnitude Quake Hits North Japan

    https://www.bloomberg.com/news/articles/2022-03-16/7-3-magnitude-quake-hits-north-japan-tsunami-alert-issued
  30. M

    What is magnitude of dynamic force?

    Summary:: In a mass-spring system they talk about 'magnitude of dynamic force', what is meant with that? Hi! In a mass-spring system I read about the term: "magnitude of dynamic force" (see sketch). What is meant with that? I the end this is used to determine the accuracy as I understand it...
  31. G

    To find direction and magnitude of forces acting in a system

    Please could I ask for help with the following: Here is my diagram, I show the rod displaced from the sphere so as to label the internal forces acting on each of the rod and the sphere: In the diagram below I have added the line through DE at angle ꞷ the the horizontal, and a few other...
  32. D

    Magnitude of force acting on wedge and block

    Clearly if ##F = 0## and ##\tan\theta > \mu_s##, then using the above equations for ##f_s## and ##n##, we get ##f_s > \mu_s n## so the block will slip. However, it seems that as long as the force ##F## is directed to the right with a certain minimum magnitude, namely ##\frac{\tan\theta -...
  33. D

    Magnitude and average value of energy intensity of light beam

    I tried using the equations above, but I wasn't really able to come up with an intuitive explanation. From my understanding, the electric field vector only varies in the x-y plane while the magnetic field vector only varies in the z-y plane. Also, both vary sinusoidally and both reach extrema...
  34. O

    Off by order of magnitude when calculating how much calcium is in bone

    I think I have the answer, but when I calculate it out, I'm off by at least an order of magnitude. My process goes like this: The (looked up) specific activity of Ca-49 is ##1.63*10^7 TBq/g##, which is ##1.63*10^{16} KBq/g## The activity of the sample after 5 minutes rest is ##166KBq##, per...
  35. M

    Magnitude of the Projection of force "F" on the u-axis

    So I was watching a YouTube video preparing for a quiz on Wednesday, and I saw something that I would like clarification on. I'm pretty sure I understand what is being explained, but I just want to confirm. The figure above is associated with the problem at hand. So I understand that to get the...
  36. guyvsdcsniper

    Magnitude of the flux through a rectangle

    I have attached the work to this problem and although it has different parameters than what I have listed in my post the basis to solving the problem is the same. I am confused on why this rectangle in this problem is considered to b in the j unit vector direction. Is it because its face will...
  37. L

    Finding The magnitude of the velocity

    i have tried V=Vi - (g*t) with an answer equals to 4 as well as d=Vi(t) + 1/2 a t^2 with an answer equals to 19 my final asnwer was 1.43 and it was still wrong i used formula a=v/t v=14 t=10 i divided 14/10 to get 1.4
  38. D

    Finding the Magnitude and Angle of a Problem: Two Solutions

    Hello, I solved this problem two ways and got the same value for the magnitude but different values for the angle. I am wondering which is correct. I showed my work, so I hope someone can tell me if one method is just invalid.
  39. S

    B Geometrical meaning of magnitude of vector product

    My notes says that the geometrical meaning of $$|\vec v \times \vec w | $$ is the perpendicular distance from point ##V## to line passing through ##O## and ##W## (all vectors are position vectors) $$|\vec v \times \vec w | = |\vec v| |\vec w| \sin \theta$$ From the picture, the perpendicular...
  40. jisbon

    Engineering How to Calculate the Magnitude and Phase of the Transfer Function H(e^{jw})?

    Tried this, but not sure how am I supposed to square the whole equation and then square root it since this will inevitably give me imaginary values. Am I supposed to ignore the imaginary values? Also, how can I find out the phase in this case? Usually, it's taking the exponents but in this case...
  41. G

    What are the factors influencing Error Vector Magnitude (EVM)?

    Error Vector Magnitude is widely used in the telecommunication industry to assess the performance of the users. In the given formula, Sr(n) is the received symbol and St(n) is the ideal symbol. N is the total number of symbols received. I have a Multi-User MIMO system simulation where there are...
  42. V

    Magnitude of electric field E on a concentric spherical shell

    The only explanation that I have seen in textbooks is that since the outer spherical shell is symmetrical relative to internal charged spherical shell so field every where on the outer shell is same in magnitude at every point on it. I can understand that electric field needs to be...
  43. B

    I Why is (N dot N) different for magnitude than for X, Y, Z components?

    I have to perform a calculation on my data. Here is an example of data from just one time step (data from other time steps would appear as additional rows). X Y Z Total 2 2 1 3 Total = SQRT(X2 + Y2 + Z2). The calculation I have to do is: (N • N), where "N" is an average. I tried...
  44. Michael c17

    Need help with Finding absolute magnitude

    P is = to 7 and I don't know how to get the absolute magnitude please help.
  45. H

    What is the maximum electric field magnitude between the cylinders?

    I used a couple ways to do this question, but I got neither correct. Can someone help, please? Thank you. 1. E= V/r = 700 / (60*10^-3) = 11667 (very far from the given answer) 2. E = (-kQ/r)⋅ dr = kQ/r^2 = kQ/ [( 1/20/ 10^-3)^2 - (1/80/10^-3)^2] (For this method, I stuck...
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