Area is the quantity that expresses the extent of a two-dimensional region, shape, or planar lamina, in the plane. Surface area is its analog on the two-dimensional surface of a three-dimensional object. Area can be understood as the amount of material with a given thickness that would be necessary to fashion a model of the shape, or the amount of paint necessary to cover the surface with a single coat. It is the two-dimensional analog of the length of a curve (a one-dimensional concept) or the volume of a solid (a three-dimensional concept).
The area of a shape can be measured by comparing the shape to squares of a fixed size. In the International System of Units (SI), the standard unit of area is the square metre (written as m2), which is the area of a square whose sides are one metre long. A shape with an area of three square metres would have the same area as three such squares. In mathematics, the unit square is defined to have area one, and the area of any other shape or surface is a dimensionless real number.
There are several well-known formulas for the areas of simple shapes such as triangles, rectangles, and circles. Using these formulas, the area of any polygon can be found by dividing the polygon into triangles. For shapes with curved boundary, calculus is usually required to compute the area. Indeed, the problem of determining the area of plane figures was a major motivation for the historical development of calculus.For a solid shape such as a sphere, cone, or cylinder, the area of its boundary surface is called the surface area. Formulas for the surface areas of simple shapes were computed by the ancient Greeks, but computing the surface area of a more complicated shape usually requires multivariable calculus.
Area plays an important role in modern mathematics. In addition to its obvious importance in geometry and calculus, area is related to the definition of determinants in linear algebra, and is a basic property of surfaces in differential geometry. In analysis, the area of a subset of the plane is defined using Lebesgue measure, though not every subset is measurable. In general, area in higher mathematics is seen as a special case of volume for two-dimensional regions.Area can be defined through the use of axioms, defining it as a function of a collection of certain plane figures to the set of real numbers. It can be proved that such a function exists.
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If a planar wire loop is moved through a homogeneous magnetic field (field lines perpendicular to the loop plane) with constant velocity and no rotation, Lorentz force will move some electrons to one side of the loop, creating a potential difference. But how does this work with Faraday's...
Homework Statement
I'm reading a paper and I'm trying to understand how does the author arrived from equation (1) to the following buckling load equation (2). I know that the author substitutes equation (1) with the dimensions of the geometry but I still could not understand how he comes to...
Homework Statement
Find the area between the parametric curve, x(t)=cos(t), y(t)=sin^2(t) and the x-axis
Homework Equations
- A = ∫ₐᵇ y(t) x'(t) dt
The Attempt at a Solution
=http://imgur.com/a/UA48d - My work shown in the link provided without the bounds, sorry for not rotating the image and...
Hey guys, I'm trying to teach myself physics and ran into a problem. I've recently been trying to calculate how much light is being bent in a certain area. I think we'd have to use integrals? I came up with this little formula, but not sure if it's right. If anyone can help me, that'd be much...
Hi everyone! Since this is a physics forum, I was curious which area of physics research did you specialize in, so I set up this poll.
Please note the following:
1. My question is directed to current physics students, postdocs, and faculty members. You can also answer if you have completed a...
I am learning about shearing stress, and I am a little confused about the area of projection mentioned in my book. When it introduces it, it shows a plate with a rivet through it. The plate is of thickness t, and the diameter of the rivet, d. It shows the plate and the rivet cut in half by a...
I know that the height is not 2 somewhere around 1.9 or 1.85 which is the f()
It is x = 1.0 and x = 1.5
and the strip of the shaded is 0.5 unit wide
Somehow i can get the asnwer
Homework Statement
Pressure is 8 kPa, mass is 10 kg, length of one side of rectangle is 1.2 m
Find width of rectangle
Homework Equations
P=F/A
N = kg * m * s^-2
The Attempt at a Solution
8kPa = (10kg * 10m/s) / (1.2 m * X m) /// X is the unknown width
8000Pa = 100N / 1.2X m^2...
Workings
$\triangle ADE \cong \triangle CFE \left(AAS\right)$
$\angle AED = \angle CEF $( vertically opposite angles )
$\angle CFE= \angle EDA $( alternate angles )
$AE=EC $( E midpoint )
$ii.$ADCF is a parallelogram because diagonals bisect each other.
Where is help needed
How should...
Homework Statement
We are given a Banana, and asked to find the volume and surface area of the function, using calculus. So far, we have learned elementary calculus (derivatives, limits, and integrals) as well as volumes of revolutions. We traced the banana on graph paper, plotted points on the...
we interest one V-Sorb 2800 BET surface area analyzer, using physical adsorption principle to test particles surface area data, if anyone knows this analyzer principle?
Homework Statement
A 5-foot long cylindrical pipe has an inner diameter of 6 feet and an outer diameter of 8 feet. If the total surface area (inside and out, including the ends) is k*PI , what is the value of k?
Homework Equations
In my view the formula should be:
2* PI * radius * h + 2*PI *...
Homework Statement
How does the method of cable installation and other external factors influence the required cable cross sectional area for a given circuit
Homework EquationsThe Attempt at a Solution
I've been searching for the answer for this for ages. I only find answer relating to types...
Rectangle $ABCD$ ,point $P$ on $\overline{AB}$ and point $Q$ on $\overline{DP}$ respectively
given: $\overline{AB}=14,\overline{CP}=13$. and $\overline{DP}=15$, if $\overline{CQ}\perp \overline{DP}$ on $Q$
please find the area of $\triangle ABQ$
Homework Statement
A football field is given in the following shape, where, ABCD is a square of side-length and AEB, CFD are semi-circular arcs. If an observer is moving with uniform velocity .along AB, what is the area of the football-field measured by the observer? ( is the velocity of light...
Homework Statement
So it's given the pipe has a inside diameter of 60cm and outside diameter of 70cm. the two ropes AC and AB are separated by a spreader bar. Wants us to find tension in the ropes. Also give is the density of concrete which is 2320kg.
Homework Equations
pi(r)^2*L=Area
The...
Homework Statement
http://www.chegg.com/homework-help/questions-and-answers/figure2-shows-pneumatic-circuit-four-actuators-controlled-state-sequence-cylinders-operate-q13517089
this question is what I am undertakingHomework Equations
none
The Attempt at a Solution
a, state the sequence in...
Can I have an opinion on this question, please? Personally I would use the cosine & sine rules to work out the angles then use trig to calculate the height. However, the question asks for Pythag to be used. Can someone please explain what method I should be using to answer this? Thanks
Thanks
Carla
Here is my formula for the area of n layers of appolonian gasket(assuming no circles past the nth layer):
$$πR^2 - (πR^2 - (\sum_{0}^{n} x_n*πr_{n}^2))$$
Here R is the radius of the outer circle, r is the radius of an inner circle, x is a function that represents the number of circles in a...
(0, 0), (3, 5), (1, 8)
Find the slopes and equations for each line
(0,0) ----> (3,5) = 5/3x
(0,0)---->(1,8) = 8x
(1,8)---->(3,5) = -3/2x+ 19
Then I set up the integrals (on x)
Integral sign from 0 to 1 (8x-5/3x)dx + Integral sign from 1 to 3 [(-3/2x+19)-5/3x) dx
I got 117/4 as an...
I live in the Virginia suburbs of Washington DC where the light pollution is such that it is impossible to ever see the Milky Way in the sky. Where is the closest place one could go to actually see the Milky Way and more stars?
Calculate the area of water, suspended at 500m, needed to produce 23TWh of energy
I've done a calculation but the answer seems far too small
If I needed to store the UK's supply of energy for three months i.e. 23TWh of energy
in a reverse pump hydro storage at an elevation of 500m
using
P=mgh...
Hawking area theorem says that area of black hole generally never decrease. Penrose process says that energy can be extracted from black hole. Energy extraction will decrease mass? if yes then if mass is decreased then will area also decrease?
I am confusing things here :(
Maybe, it's a useless question. The figure which I'm talking about consists of two parallel lines each of length 'b' and are separated by a distance 2r. Their ends on one side is closed by a semicircle which in pointing inwards and decreases the area and the ends on the other side are joined by...
Calculate the area of the region bounded by the graph of the function y = 8 – 2x - x^2 and the x-axis
Y = 8 - 2- x^2
0 = 8 – 2 – x^2
(-x – 4)(x – 2)
- x – 4 = 0 and x – 2 = 0
-x = 4 x = 2
X = - 4
Do I do this?
Y = 8 -2x -x^2
= 8x - (2x^2)/2 - x^3/3
= 8 -...
Hi PF!
Suppose we have a differential area element ##dA##. This can be expressed as ##dx \, dy##. However, a change in area ##dA## seems different. Take positions ##x## and ##y## and displace them by ##dx## and ##dy## respectively. Then the change in area ##dA = (x+dx)(y+dy)-xy = xdy+ydx##...
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I was perplexed as to why the area on which the pressure acts is 'piR^2'. Since one complete half of the sphere is in contact with the gas, hence the pressure should be 4piR^2/2 (half of the surface area of sphere i.e 2piR^2)
Hi, I am stuck on this question and was wondering if anyone could help me. The topic is integral equations.
A block of land is bounded by two fences running North-South 5 km apart a fence line which is approximated by the function N=0.5E and a road which is approximated by the curve...
The problem reads: "You are given a string of fixed length l with one end fastened at the origin O, and you are to place the string in the (x, y) plane with its other end on the x-axis in such a way as to maximise the area between the string and the x axis. Show that the required shape is a...
Homework Statement
Find the surface area of portion of plane x + y + z = 3 that lies above the disc (x^2) + (y^2) < 2 in the first octant ...
Homework EquationsThe Attempt at a Solution
Here's the solution provided by the author ...
I think it's wrong ... I think it should be the green...
Recently I did an experiment where I dropped a magnet through a tube that was surrounded by a coil, and I hoped to investigate a factor that would affect the current induced (Faraday's law). I chose to study the effect that changing the cross-sectional area of the wire had on the induced...
Hi,
given an Hydraulic Cylinder with the Formula:
F=p*A
Why do we use APiston to calculate the Force in Work-Direction? Doesnt it suppose the "Potential Energy" of the compressed air just presses in that Area?
Im pretty confused, sorry about the unconcrete question.
So I'm currently a senior undergraduate nuclear engineer at a respected university and I've been considering getting my Ph.D for a while now. I'm having difficulty deciding on a specific research area, however. I'd like my research, optimally, to be applicable outside the nuclear sector as well...
I have tried to apply greens theorem with P(x,y)=-y and Q(x,y)=x, and gotten ∫ F • ds = 2*Area(D), where F(x,y)=(P,Q) ===> Area(D) = 1/2 ∫ F • ds = 1/2 ∫ (-y,x) • n ds . This is pretty much the most common approach to an area of region problem. But here they ask you to prove this bizarre...
I've read that the surface area of an object in contact with the ground doesn't not affect the frictional force acting on it as it is pushed forward.
I kinda understand what is explained but I find it difficult to reconcile with what happens in real life...
Don't wheels reduce the surface...
:D I have trouble in determining the ratio of the area of $\triangle PST$ in terms of $\triangle PQR$
In the triangle PQR $QT=TR$, $PS=1 cm$ , $SQ=2 cm$ , How should I be writing the area of $\triangle PST$ in terms of $\triangle PQR $
What is known by me :
Since...
In the figure , the area of triangle $ABC$ is twice that of triangle $BCD$.USing the given information , find the ration of the area of the triangle $CFG$ to the area of triangle $BEG$
Hint- Use the midpoint theorem.
(Wave) Stuck in this problem & currently I have no workings to show.
Hello,
I've done something similar to this before but this question is really different because it contains two shapes. Now I'm really confused and I really appreciate the help~!
-Cheers
Homework Statement
For σBC end , i don't understand how the author get (20mm)(40mm-25mm) = 300x10^-6 (m^2) ...
Homework EquationsThe Attempt at a Solution
IMO, , the area should be the circled part (thin rectangular part of the rod) , but i only know one dimension only , which is 40mm , i don't...
Friction is independent of area of surfaces in contact as long as the normal reaction remains the same.I agree that it does not depend and so says it's formula but the condition that it does when the normal reaction remains same looks odd to me..Can someone help me out to understand this?
I wonder why projected area has been of much interest among physics communities, while the surface area could well be the solution unless any complex geometries are involved.
The question popped up in my head when the surface tension in a water jet was derived. Clearly the jet has a circular...
There's a rectangle which the length is x+1 and the breadth is x.
X is -1\pm\sqrt{11}
Show that the area is 11-\sqrt{11}
The workings I have done for far are below.
(-1\pm \sqrt{11})*(-1 \pm \sqrt{11} +1)
(-1\pm \sqrt{11})*( \pm \sqrt{11} )
(-1\pm \sqrt{11})*( \pm \sqrt{11} )
(-1\pm...
I found this on the Internet . The formula is
Surface Area = R^2 \displaystyle \int _0 ^ {2 \pi} \int _{0}^{\pi} \sin \theta d \theta d \phi
I'm wondering why the limit of θ is from 0 to π only ? why not from 0 to 2π ? Because it's a perfect sphere...