What is Perpendicular: Definition and 506 Discussions
In elementary geometry, the property of being perpendicular (perpendicularity) is the relationship between two lines which meet at a right angle (90 degrees). The property extends to other related geometric objects.
A line is said to be perpendicular to another line if the two lines intersect at a right angle. Explicitly, a first line is perpendicular to a second line if (1) the two lines meet; and (2) at the point of intersection the straight angle on one side of the first line is cut by the second line into two congruent angles. Perpendicularity can be shown to be symmetric, meaning if a first line is perpendicular to a second line, then the second line is also perpendicular to the first. For this reason, we may speak of two lines as being perpendicular (to each other) without specifying an order.
Perpendicularity easily extends to segments and rays. For example, a line segment
A
B
¯
{\displaystyle {\overline {AB}}}
is perpendicular to a line segment
C
D
¯
{\displaystyle {\overline {CD}}}
if, when each is extended in both directions to form an infinite line, these two resulting lines are perpendicular in the sense above. In symbols,
A
B
¯
⊥
C
D
¯
{\displaystyle {\overline {AB}}\perp {\overline {CD}}}
means line segment AB is perpendicular to line segment CD. For information regarding the perpendicular symbol see Up tack.
A line is said to be perpendicular to a plane if it is perpendicular to every line in the plane that it intersects. This definition depends on the definition of perpendicularity between lines.
Two planes in space are said to be perpendicular if the dihedral angle at which they meet is a right angle (90 degrees).
Perpendicularity is one particular instance of the more general mathematical concept of orthogonality; perpendicularity is the orthogonality of classical geometric objects. Thus, in advanced mathematics, the word "perpendicular" is sometimes used to describe much more complicated geometric orthogonality conditions, such as that between a surface and its normal.
Homework Statement
Find the distance from the point A = (1; 0; 2) to the plane passing through the point (1; 2; 1) and perpendicular to the line given by the parametric equations x = 7, y = 1 + 2t, z = t - 3.
Homework Equations
d = | (PS dot n)/|n||
The Attempt at a Solution
Set n = <0...
Consider a pole of 1 light second long in the ##y## direction (the vertical line(s) in the enclosed figure). It is moving in the ##-x## direction. According SR, the pole's length is not contracted because its length is not parallel to the propagation direction. However, given the time of flight...
Cross product is used to find the perpendicular vector of two vectors. If there is any two vectors in a plane then there is always a perpendicular vector to both of them.
So in circular motion if the motion is horizontal then is there a perpendicular force to the object in circular motion?
Why is the slope of perpendicular line on the the other defined this way:
m = slope of a particular line
m'= slope of the perpendicular line on that particular line
m*m' = -1 OR m' = -1/m
Thanks
Homework Statement
Given a line ##l## and a point ##B\in l## in a protractor geometry, there exists a unique line ##l'## that contains ##B## such that ##l\perp l'.##
Homework Equations
None
The Attempt at a Solution
I am not sure how to prove uniqueness or existence in this...
Homework Statement
Determine for what value/s of the parameter a the following planes in R3 are perpendicular:
ax + 0y - 5z = 3
ax + ay + 5z = -26
Write answer in form {a,b} or {a}
Homework Equations
I know that in R2 two vectors are perpendicular if
u*v = 0
What what do I use for...
Homework Statement
If \underline{v} = a\underline{i} + 2\underline{j} + 3\underline{k} and \underline{w} = 2\underline{i} +b\underline{j} - \underline{k} and |\underline{v}| = |\underline{w}|, find the values of a and b so that \underline{v} and \underline{w} are perpendicular.
If v =...
Does Casimir plates prevent photon existence only perpendicular to them?
I mean, Casimir attraction arises from the fact that the plates prevent some wavelenghts of photons to exist in between them, so an imbalance arises and pushes the plates together, right?
But what about photons in other...
Homework Statement
You are given that with x = (x1,x2), y = (y1,y2), the formula
(x,y) = [x1 x2] [2 1;1 2] [y1;y2] (where ; represents a new row).
is a inner product for the vectors in R2
Using this inner product, find a unit vector perpendicular to the vector (1,1)
Homework Equations
The...
Homework Statement
If the graphs of A1x + B1y = C1 and A2x + B2y = C2 are perpendicular, express the following in terms of A2 and B2.
A1/B1= ?
Homework Equations
Negative reciprocal
The Attempt at a Solution
I thought that by expressing A2 and B2 with A1/B1, it would just...
I was just wondering why a body immersed in a fluid at rest experiences a perpendicular force on its surface? Why can't there be a component of force in parallel direction to the surface ? I read somewhere that this would cause the fluid to flow parallel to the surface but i don't quite...
Homework Statement
Show that the product of the perpendicular distance problems drawn from the points (√5, 0) and (-√5, 0) on the line 2xcosα-3ysinα=6 is independent of α
Homework Equations
Eqn of perpendicular distance Ax1+By1 + C/ (A^2 +B^2)^1/2 The whole formula will be within the...
I'm learning vectors. I read somewhere that if a vectors magnitude is constant, then its derivative is perpendicular. However, in polar co-ordinates, I learned something else.
The distance of a particle in orbit from a focus is r. if /r/ varies with t even then dr/dt is v and it is...
Homework Statement
Calculate the moment of inertia of a uniform, solid cylinder about it's perpendicular axes. The cylinder has length L, radius R, and total mass M. It is centered on the origin with the z-axis running through the center of it's circular faces.
Homework Equations
I =...
Sorry to ask another question :/
Homework Statement
Consider the change of momentum.
A wind (of speed v) acts perpendicularly to a wall. Show that the pressure do to this wind acting of the wall is v2ρ, where ρ is air density.
Hence show by suitable integration that the torque about the...
Homework Statement
Find the equation of the line, p, that is perpendicular to r=(1,1,1)t + (3,5,2) and passes through (3,3,1)
Homework Equations
dot product =0
The Attempt at a Solution
I understand that the direction vector r and p, when dot producted must =0
but I've forgotten...
Hi -
I was reading Adams' "Calculus: A Complete Course" (6th edition) and he offers the following proof that the gradient of a function:
I'm just wondering why the emphasis on specifying the values of x(0) and y(0), or even the need to specify t = 0 in the last statement? If \mathbf{r} is...
Homework Statement
Hi everyone, I am generalizing the following problem because I disagree with how the book solves the problem.
A square mass 'm' is attached to two springs with identical constants 'k', in a configuration such that the springs mount to the left/right sides of the...
Homework Statement
A laser beam of intensity I reflects from a flat, totally reflecting surface of area A whose normal makes an angle θ with the direction of the beam. Write an expression for the radiation pressure Pr[θ] exerted on the surface, in terms of the pressure Pr[p] that would be...
The experiment of a quickly rolling wheel on a string is well known.
How is this behavior explained in terms of the molecules of an atom? That is to say, why don't the individual atoms of the wheel fall down?
Homework Statement
http://imageshack.us/a/img812/8836/5tfn.jpg
Uploaded with ImageShack.us
Find F such that the moment around A will not exceed 1000N*m for any value of θ.
Homework Equations
M = fdThe Attempt at a Solution
I got the right answer, I found the distance of a -> b
AB= √( (2^2)...
i'm given some line and a point (not on that line), and i want to find a line that is perpendicular to given line and passes through the given point.
here is what I've tried so far. please tell me where i went wrong.
given line:
x=at+x0
y=bt+y0
z=ct+z0
given point: P(Px,Py,Pz)
my method is...
Homework Statement
1)Give a unit vector
a) in the same direction as v=2i +3j
b)Perpendicular to v
2)
a) Find a vector perpendicular to the plane z=2+3x-y
b)Find a vector parallel to the plane
Homework Equations
The Attempt at a Solution
1) a)
Method 1:
u=v/||v|| so i...
Yes, I understand the equation for the cross product and the right hand rule.
People keep using this example with a wrench twisting a bolt and the right hand rule makes sense there. Okay fine, the force is perpendicular in that case...
But suppose there is no bolt grooves.
The bolt...
Homework Statement
Resolve the force F into
a) a part perpendicular to AB and
b) a part parallel to BC
Homework Equations
a dot b = ab*cos(θ)
The Attempt at a Solution
I attached my attempt in the .pdf file. For some reason it is wrong. I don't understand how my reasoning is...
Hi PF-members.
My intuition tells me that: Given a divergence free vector field \mathbf{F} , then the curl of the field will be perpendicular to field.
But I'm having a hard time proving this to my self.
I'know that : \nabla\cdot\mathbf{F} = 0 \hspace{3mm} \Rightarrow \hspace{3mm}...
Homework Statement
The coordinates of the particle is given by:
x(t)=(1.2 m/s)t
y(t)=15m-(0.5m/s2)t2
a) At what times is the particle's velocity perpendicular to its acceleration
b) At what times is the particle's speed instantaneously not changing (I get that the acceleration is...
Homework Statement
I'm trying to solve the following problem :
In △ABC, coordinates of B are (−3,3). Equation of the perpendicular bisector of side AB is 2x+y−7=0. Equation of the perpendicular bisector of side BC is 3x−y−3=0. Mid point of side AC is E(11/2,7/2). Find AC2.
Homework...
Basically I don't know anyone in real life that can help me with this, so I need help checking to see if my answers are correct :)
PART A
3) Solve 2x^2 + 4x = 15 by using the quadratic formula.
x = -1 +/- 2sqr34
4) Determine whether the given pairs of lines are parallel, perpendicular, or...
Homework Statement
A particle is projected from a point o with initial velocity u up a plane inclined at an angle 60° to the horizontal. The direction of projection makes an angle ∅ with the horizontal. The maximum perpendicular height is H.
prove that H = u^2( sin^2(∅) ) / g
Homework...
Homework Statement
What is the equation of the line perpendicular to ## x^2-y^2=1 ## at the point ## (2,\sqrt{3}) ##?
Homework Equations
The Attempt at a Solution
I would automatically know what to do if I could use calculus, but apparently you can solve this without it. I would also...
[b]1. Two semi infinite conducting plates at right angles to each other, we bring in a charge q from infinity to point (a,b) what is the energy involved in doing so?
Homework Equations
coulomb's law and method of images in griffith.
The Attempt at a Solution
force can be easily...
I am trying to understand Gaussian curvature. This led me into looking at principle curvature. Now If one takes a look at the picture of the "Saddle Surface" on Wikipedia here: http://en.wikipedia.org/wiki/Principal_curvature
I see that at the point p on the saddle where curvature goes both...
Orthogonal polynomials are perpendicular??
hi..
So as the title suggests, i have a query regarding orthogonal polynomials.
What is the problem in defining orthogonality of polynomials as the tangent at a particular x of two polynomials are perpendicular to each other, for each x? This...
Most physicists are familiar with the representation of vectors perpendicular to the plane (\otimes and \odot) which look like the fletching or head of an arrow, commonly used to represent magnetic fields, currents and so on.
Can anyone tell me the name of this representation? Does it even...
Homework Statement
The grains of the wooden member forms an angle of 15° with the vertical. For the state of the stress shown, determine (a) the in-plane shearing stress parallel to the grain, (b) the normal stress perpendicular to the plane.
I have attached an image of the question...
Here is the question:
Here is a link to the question:
Please help, How to show if a tangent vector is perpendicular to r(t)? - Yahoo! Answers
I have posted a link there to this topic so the OP can find my response.
The vectors \left(\frac{2x}{x-3}\right) and \left(\frac{x+1}{5}\right) are \perp for 2 values of x
what is the quadratic equation which the 2 values of x satisfy
well I got 2x^2+7x-15 which gives x=-5 and x=\frac{3}{2}
-5 seems to work but
\frac{3}{2} doesn't or is there another way...
Homework Statement
z+ up with E field, y to the right, x out of the page with B field
particle released from rest at (0,0,0) with only initial y velocity y=(E/B)t
or initial y=(E/2B)t
Homework Equations
can you suggest a good differential equations text...
Homework Statement
Wire Ia and wire Ib are infinitely long and perpendicular to each other, separated by distance d. Wire a has current Ia and the direction of current is into the page. Wire b has current Ib and the direction of current is straight up. What is the force per length of Ia on Ib...
Why is the cross product of two vectors perpendicular to the plane the two vectors lie on?
I am aware that you can prove this by showing that:
(\vec{a}\times\vec{b})\cdot\vec{a} = (\vec{a}\times\vec{b})\cdot\vec{b} = 0
Surely it was not defined as this and worked backwards though. I...
I hope I managed to post my question the right place!
I have a body consisting of a bunch of mass-points in ℝ^{3}, and when torque is applied to this body, I'm interested in finding the force that must have caused the torque based on the point of application and the torque vector, which are...
Homework Statement
I was just wondering, so let's say there are two current carrying wires in the same plane that are perpendicular. One of them is infinite length, the other is a wire segment some distance away from the first one and perpendicular to it. What's the force on the wire...
Homework Statement
Prove that when speed is constant that V(T), and A(T) are perpendicular.
Homework Equations
I know this involves the dot product to show that the dot product of the vectors is zero.
The Attempt at a Solution
In my head I thought that since the speed is...
As students taking pre-calculus, you are probably aware that when two lines are perpendicular, the product of their slopes is -1. Let's see why this is.
Let one line be $\displaystyle y_1=m_1x+b_1$ and the other line be $\displaystyle y_2=m_2x+b_2$.
Now,we know the angle of inclination of a...
Why do we have x-axis perpendicular to y-axis? Why not 45° or something else?
Even if we keep any other angle other than 90° we can still build up all other vectors using them in the plane.
So what is there is 90° that makes it special and simpler?
Hello Everyone,
I have a question concerning the "Area perpendicular to the magnetic field".
If the field was produced by a permanent magnet, would the "Area perpendicular to
the magnetic field" be the same size as the Area of the permanent magnet?
Homework Statement
Find a plane through the origin that meets the plane M : 2x + 3y + z = 12 in a right angle. How do you know your plane is perpendicular to M?
Homework Equations
Honestly have no idea... I know how to find an equation for a plane given a normal and a point, however...