# What is Planes: Definition and 542 Discussions

Planès is a commune in the Pyrénées-Orientales department in southern France.

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1. ### Electric field at the edge of half planes

I assumed the plate areas to be ##S## , then electric field at ##P## should be $$E_P=E_{+\sigma}-E_{-\sigma}=\frac{k\sigma S}{h^2}-\frac{k\sigma S}{(h+d)^2}\approx \frac{2k\sigma S d}{h^3}$$ but i think it's wrong here as ##P## lies at the edge , so it won't recieve electric fields in a way...
2. ### Germany painting airlines to look like beach towels

I just saw this coming in for a landing at Toronto International. https://www.dailymail.co.uk/travel/travel_news/article-10710607/German-airline-Condor-unveils-planes-painted-like-beach-towels.html
3. ### Finding line where two planes intersect

For this problem, The solution is, However, I could not get that. By getting the system in REF, I got ##x = 3 + \frac{3}{7}z ## and ##y = \frac{1}{7}z##. Therefore z is a free variable so ##x = 3 + \frac{3}{7}t = 0## and ##y = \frac{1}{7}t##. Thus equation of line is ##x\hat i + y\hat j +...
4. ### I What are the significant angles between intersecting planes in 4D space?

Suppose I have two intersecting planes in a four dimensional space. It seems to me that there are two angles between these planes. If the two planes intersect in a line then one of those angles is zero. If the two angles are non-zero then the planes intersect in a point. If one plane is the...
5. ### Find the electric field everywhere resulting from two infinite planes

What I don't understand is how come the electric field of the negative plane isn't pointing towards the positive plane (in blue) and cancelling out the electric field of the positive plane (in red). See image
6. ### Determine a unit vector perpendicular to the given planes

I looked at this question and i wanted to ask if we could also use; ##C## =## c_2 ##(##-\dfrac {3}{2}i## +## j - 3k)## ... cheers This problem can also be solved by using the approach of cross product ##A×B##...
7. ### Equilibrium of a stiff plate on inclined planes

I HAVE NO IDEA HOW TO START.ONLY THINGS I KNOW ARE WHAT I RERAD ON THIS THRED. https://www.physicsforums.com/threads/equilibrium-of-a-stiff-plate-on-inclined-planes.947601/I can't continue from there. There are also questions where α=β, α+β=45 and where α=45,β=60.How to make use of the fact...
8. ### How did WW II planes with tail wheels taxi?

The tail wheels on many WW II planes look tiny. How did pilots steer these planes when taxing? Was it by using the tail wheel? If so, what control was used to turn the tail wheel ? - some sort of steering wheel separate from the other flight controls?
9. ### Using virtual work to find the angle of a bar supported by two planes

I imagined the bar slipping along a virtual displacement, with the top and the bottom slipping by equal amounts. Since the planes are orthogonal, I took the components of these displacements: the lower end is displaced Lsinα in the direction of the right plane and by Lcosα in the direction of...
10. ### How can I add Moments / Torques in different planes?

I have a problem as shown in the figure So assume there is a cylinder rotating inside a stationally wall. There is a viscous fluid in between the gap of cylinder wall and outer stationary wall, similar to bearing. The fluid has some velocity in axial direction also the outer wall of cylinder...
11. ### Question about the role of mass in inclined planes

Hi! I have a question about inclined planes. In the diagram I attached, you can see that, with or without friction, mass does not affect the acceleration of the block. However, in my experience, the more people I put on my sled, the faster it goes. Why is this?
12. ### 3 Different and not parallel planes

b) The Points on L1 satisfy the equations of the planes P1 and P2. The Points on L2 satisfy the equations of the planes P2 and P3. The Points on L3 satisfy the equations of the planes P1 and P3. Let v1 be a vector along L1 which lies on both planes P1 and P2. Let v2 be a vector parallel to v1...
13. ### Understanding Principle Stress Planes: Exploring Shear Forces and Rotation

All the materials that I have been reading, it says that when the element is rotated to a θ, this will be called the principle stress plane with no shear force acting on it. but visually when you rotate the element, there will be a shear force acting parallel to the plane. I am very confused...
14. ### I Three equations of planes, dimension should be 1?

I always thought that one independent equation cuts down the dimension by 1, so if we had two planes, say x - y - z = 1 and x + y + z = 1, then because these are two independent equations, the dimension of the intersection should be 1 because each plane is cutting down the dimension by 1. Using...
15. ### Ratio of acceleration of two solid cylinders released on two inclined planes

I am not sure about my free body diagram. I assume the cylinder rolls without slipping so the forces acting on the cylinder are: Weight directed vertically downwards Normal force directed perpendicular to the plane friction directed upwards, parallel to the plane Am I correct till this point...

31. ### Are these birds, planes or satellites, or meteors?

Dear experts, What are these things (dozens of them): Are these birds, planes or satellites, or meteors? Has anyone seen anything like these?

rt a)
33. ### MHB Planes 1 & 2 Intersect: Find Scalar Equations

Two planes, plane 1 and plane 2, intersect in the line with symmetric equation (x-1)/2 = (y-2)/3 = (z+4)/1. Plane 1 contains the point A(2,1,1) and plane 2 contains the point B(1,2,-1). Find the scalar equations of planes plane 1 and plane 2. I have no idea how to do it, all help will be...
34. ### Line of intersection of two planes

Homework Statement Find equation of line of intersection of planes r.(3i-j+k)=1 and r.((i+4j-2k)=2 Homework Equations a x b gives a perpendicular vector to a and b...(i) The Attempt at a Solution to write equation of a line r=a+tb we need a point a on the line and a parallel vector b. Taking...
35. ### I have a hard time with kinematics involving inclined planes

Homework Statement Two blocks of mass m1 = 3.00 kg and m2 = 6.00 kg are connected by a massless string that passes over a frictionless pulley (see the figure below). The inclines are frictionless. Image - https://www.webassign.net/serpse9/5-p-049.gif The inclined plane is shaped like a...
36. ### How to determine the volume of a region bounded by planes?

Homework Statement Let G be the region bounded by the planes x=0,y=0,z=0,x+y=1and z=x+y. Homework Equations (a) Find the volume of G by integration. (b) If the region is a solid of uniform density, use triple integration to find its center of mass. The Attempt at a Solution [/B] My...
37. ### Planes of motion for the elbow and shoulder

1. Homework Statement This is an olevel question from paper 5090 may/june 2012 paper 12 question number 24 (the snapshot is from another question paper) the answer in the marking scheme is A which clearly I cannot understand. I thought shoulder joints have 3 planes of movementHomework...
38. ### Why are 3 planes needed to define stress at a point?

My question is simple. Why do we need 9 different quantities, ie 1 normal stress and 2 shear stresses on 3 different planes, to define stress at a point? example: http://www.geosci.usyd.edu.au/users/prey/Teaching/Geol-3101/Strain/stress.html I think it should be enough to define the 3 stresses...
39. ### Equilibrium of a stiff plate on inclined planes

Homework Statement A thin stiff uniform rectangular plate with width L (L =AB) is lying on two inclined surface as shown in Fig. 3-1. The angle between the horizontal surface and the left inclined surface is α, and that between the horizontal surface and the right inclined surface is β. It is...
40. ### Two pencils of planes have a common plane

Homework Statement Find the value of the parameter α for which the pencil of planes through the straight line AB has a common plane with the pencil of planes through the straight line CD, where A(1, 2α, α), B(3, 2, 1), C(−α, 0, α) and D(−1, 3, −3). Homework Equations Let Δ be a line given by...
41. ### MHB Calculating Sphere Volume Cut by 2 Planes & Angle "e" & Distance "a

I want to calculate the volume of a sphere cut by two arbitrary plane. There is a intersection angle between these two planes, which is not 90 degrees. One of these two planes is fixed and located on plane "x-o-y", and the other is perpendicular to plane "x-o-z" and moves the distance "a" from...
42. ### Point charge with grounded conducting planes angled 120

Homework Statement The problem states: "A point charge q is located at a fixed point P on the internal angle bisector of a 120 degree dihedral angle between two grounded conducting planes. Find the electric potential along the bisector." Homework Equations ΔV = 0 with Dirichlet boundary...
43. ### Find intersections between sphere and parallel tangent planes

Mod note: Moved from a technical forum section, so missing the homework template. @fab13 -- please post homework problems in the appropriate section under Homework & Coursework. I have the following exercise to solve : I have to find all the points on the surface ##x^2+y^2+z^2=36## (so a sphere...
44. ### Basically solved, Last coordinate does not match?

Homework Statement Does the line with equation (x, y, z) = (5, -4, 6) + u(1,4,-1) lie in the plane with equation (x, y, z) = (3, 0, 2) + s(1,1,-1) + t(2, -1, 1)? Justify your answer algebraically. Homework Equations (x,y,z) = (x0,y0,z0) +s(a1.a2,b3) + t(b1,b2,b3) The Attempt at a Solution...
45. ### I Intersecting Planes: Is It Possible?

I have two 3D planes: A1*x + B1*y + C1*z + D1 = 0 and A2*x + B2*y + C2*z + D2 = 0. If you set them equal to each other it should be at the intersection. This leads to another Plane: (A1 - A2)*x + (B1 - B2)*y + (C1 - C2)*z + (D1-D2) = 0. What I want is the line of intersection in vector and...
46. Q

### A Contrast-Calculation between two planes

Hi there, I am new to the Forum! I have a little bit of a tricky Problem. I am trying to calculate the Contrast between two planes as seen here: So I started by cutting the Problem in two Parts. Part 1, The Monitor: I know the Luminance of the Monitor X, and the reflectivity of the...
47. ### How do planes discharge static electricity when refuelling?

I know that planes have static dischargers (static wicks) on the trailing edges of wings to discharge static electricity when they are flying. I was wondering how a plane, let's say with electrically resistive fibreglass wings, would discharge this without having sparks ignite while it's...
48. N

### Air pressure on planes and leak-proof containers....

On airplanes - do you know of a container or bag that will stops individual bottles with liquid from leaking/ exploding from the changes in air pressure?
49. ### Supersonic vs Suborbital planes?

So I'm watching a documentary on supersonic flight, and the challenges they describe seem SO daunting that I couldn't help but wonder: Wouldn't it just be easier to fly above (most of) the atmosphere? There must be an altitude where sonic booms no longer reach the ground and wind pressure no...
50. ### MHB Vectors in Planes: Solving for m & n, Finding Orthogonal Plane

Hiya, I have a question in high school math, vectors to be precise: The point K(3.5,-0.5,-2) is the intersection point of the plane S1: mx-7my+5z+3=0 with the line l1: (n,1,-2)+t(-1,1,0) a) find the parameters n and m b) find the equation of the plane that contains the line l1 and is...