September 2015

Jhun Vert's picture

Which line is longer, AB or BC?

Submitted by Jhun Vert on September 3, 2015 - 9:51pm

I found this illusion from the web, I found it interesting so I posted it here. The question is which line is longer, AB or BC.
 

geometry-illusion_line_01.gif

 

Do you know any geometrical illusion? One that involves mathematical concepts is more interesting. Feel free to post it here.

Rafael Abesamis Santiago's picture

Discussion on: Problem 409 Howe Roof Truss - Method of Joints

Submitted by Rafael Abesamis... on September 4, 2015 - 5:31pm

Following is a discussion on the Reviewer item titled: Problem 409 Howe Roof Truss - Method of Joints. Feel free to add your own comments!

Discussion on: Solution to Problem 503 | Flexure Formula

Submitted by Benjamin_Molina on September 7, 2015 - 7:55am

Following is a discussion on the Reviewer item titled: Solution to Problem 503 | Flexure Formula. Feel free to add your own comments!

Nay Low's picture

Discussion on: Solution to Problem 457 | Moving Loads

Submitted by Nay Low on September 8, 2015 - 7:10pm

Following is a discussion on the Reviewer item titled: Solution to Problem 457 | Moving Loads. Feel free to add your own comments!

Michael Cacanindin's picture

it is required to measure the height of a tower.

Submitted by Michael Cacanindin on September 10, 2015 - 11:43pm

it is required to measure the height of a tower. CB,which is inaccessible. from point A, in the same horizontal plane with the base C, a right triangle CAD is turned, and a horizontal line AD, 150 feet in length, is measured. At A the angle of elevation of the top of the tower is 32 degrees, at D the angle of elevation is 28 degrees. find the height of the tower

Paulo Garcia's picture

patulong naman po kung pano isolve 2.

Submitted by Paulo Garcia on September 11, 2015 - 6:46pm

plane areas

Find the area bounded by the curve y = ln x/x, the x-axis and the maximum ordinate.

ans. 1/2

Discussion on: Solution to Problem 535 | Economic Sections

Submitted by Benjamin_Molina on September 12, 2015 - 12:25pm

Following is a discussion on the Reviewer item titled: Solution to Problem 535 | Economic Sections. Feel free to add your own comments!

Ruis Raphael Hidalgo's picture

Guys help me in my ass about frustum of a regular pyramid

Submitted by Ruis Raphael Hidalgo on September 13, 2015 - 11:24pm

The lateral area of a frustum of a regular triangular pyramid is 1,081square centimeter and The altitude and the lateral edge are 24cm and 26cm respectively.Find the lengths of the sides of the bases.

Thanks please show me your solution so that I can understand thanks in advance :)

Matthew Castro's picture

Discussion on: Problem 271 | Resultant of Non-Concurrent Force System

Submitted by Matthew Castro on September 16, 2015 - 11:45am

Following is a discussion on the Reviewer item titled: Problem 271 | Resultant of Non-Concurrent Force System. Feel free to add your own comments!

Palarao Jeffrey's picture

Time rates: hot air balloon rising straight up

Submitted by Palarao Jeffrey on September 16, 2015 - 5:28pm

a hot air balloon rising straight up from a level field is track by a range finder 500ft from the point of lift off. At the moment the lift finder's elevation is 45 degrees, the angle is increasing at the rate of 0.14 rad/min. How fast is the balloon rising/

Jeremie Arellano's picture

differential equation

Submitted by Jeremie Arellano on September 17, 2015 - 3:25pm

The problem2x5y'=y(3x to the 4+y squred =0

Rigid frame calculation

Submitted by frano on September 18, 2015 - 4:34am

I need assistance with below problem:

Known are: a, h, I1, I2, q. Problem find moment at C. The beams are rigidly connected at "C"!

clipboard01.jpg

Apparently the right solution is:

Mc=q*a^2/12 * 1 / (1+2*h*I1/a*I2), while mine solution is Mc=q*a^2/12 * 1 / (1+h*I1/a*I2).

Emon Man's picture

mechanices dynamic questions: resistance to take off

Submitted by Emon Man on September 20, 2015 - 8:46pm

the jet fighter has a mass 6450kg reguries 10 seconds from rest to reach its take off speed 250km/hr under the jet thrust t 48KN compute resistance "R" during take oof?

Adz Hir's picture

solid mensuration

Submitted by Adz Hir on September 21, 2015 - 9:59pm

solid mensuration by Kern and bland
page 85

#13
Question: in the solid shown in page 84,edge AB is perpendicular to the base BDC and AEF. find the volume of the solid if BD is parallel to AE.?

page 85 #14
Question: the earth remove from a trench 8ft. deep 14ft. wide at the top and 10ft. wide at the bottom is thrown along side the trench so as to form a bank sloping on each sides at the angle to the horizontal. if the height of bank is three-fourth the width of its base. find the height of the bank.

Adz Hir's picture

solid mensuration

Submitted by Adz Hir on September 21, 2015 - 10:23pm

Solid Mensuration
by: Kern and bland
page 85

#15 Question
a block similar to the one considered in prob.3 (page 83) has a volume of 2000 cu.ft. find its altitude?

#16 Question
the space occupied by the water in a reservoir is the frustum of a right circular cone. each axial section of this frustum has an area of 8800 sq.ft. and the diameter of the lower and upper bases are in ratio 6:5. if the reservoir contains 13,600,00 gal. find the dept the water?

Tricia Dianne Sillan's picture

Solid Mensuration (Finding the weight)

Submitted by Tricia Dianne Sillan on September 23, 2015 - 6:50am

A large rectangular-shaped barge floats in a river, and a mark is made on the side at the level of the water. The
barge is 16 ft. long by 7 ft. broad. When a load of gravel is emptied into the barge, the barge sinks 4 ½ in. Find the
weight of the load of gravel. (The sides of the barge are made of comparatively thin wood, and the effect of the
immersion of the sides an extra 4 ½ in. may be neglected.

(Please help me with these questions)

Ramjet Guadalquiver Baratas's picture

patulong naman about sa maxima and minima

Submitted by Ramjet Guadalqu... on September 24, 2015 - 6:09pm

point A and B are opposite to each other on the shores of a straight river 5km wide. point F is on the same shore as B but K kilometers down the river from B. Atelephone company wishes to lay a cable from A to f where the cost per km of the cable on land is 10,000 US dollar and under the water is 12,500 US dollar. Let P be a point on the same shoreas B annd Fso that the cable runs from A to P to F.(a)if X kilometer is the distance from B to P obtain an equation defining (x) if C(x) dollars is the total cost of laying cable and state the domain of C.

Theresa Lopez Mendiola's picture

Physics

Submitted by Theresa Lopez M... on September 25, 2015 - 10:09pm

Please pahelp po :)
A mass of 20kg is projected up an inclined of 26 degrees with a velocity of 4 m/s. If the coefficient of friction is 0.2, find i) the maximum distance that the package will move along the plane. and ii) what will be the velocity of the package when it comes back to initial position.

Carlos Perez's picture

Discussion on: 013 Resultant of three forces with angles greater than 90 degree

Submitted by Carlos Perez on September 29, 2015 - 7:50am

Following is a discussion on the Reviewer item titled: 013 Resultant of three forces with angles greater than 90 degree. Feel free to add your own comments!

Stephen Jupiter's picture

Physics

Submitted by Stephen Jupiter on September 29, 2015 - 10:19pm

Patulong naman po :D

A non-uniform bar weighs 400 N and is 4 m long. When it is supported by an fulcrum at its midpoint, a load of 80 N must be supplied at the smaller end to hold the bar in a horizontal position. Where is the center of gravity?