Engineering Marathon (4 Viewers)

[arman]

Reactions
http://img440.imageshack.us/img440/3715/esttruss10001.jpg
[edit: good url]



[incomplete] Method of sections for AB

http://img440.imageshack.us/img440/5349/esttruss10002.jpg

sorry about bad scan

 

[hazza9]

Yea made a silly error missread 30kN force as 20kN

Hope i dnt do that on wednesday

Yea RAB = 130 kN

 

[arman]

Yea made a silly error missread 30kN force as 20kN

Hope i dnt do that on wednesday

Yea RAB = 130 kN

could you please explain, thanks

 

[hazza9]

I'm sayin that when I tried to solve it i misread the 30kN force as 20kN and thats why i got it wrong.

Your right arman. When i redid it i got the same as you. But i still can't get the force in AB

 

[arman]

looking at my old working, so hard to follow, ive used perpendicular distances between point A and member between Rb and B to find the force in that member which is 92kN

then it says take moments about point C which ison RHS of truss opposite Rb making up square A-Rb-B-C

thats where it stops

 

[arman]

Edited

http://img149.imageshack.us/img149/5822/estquestionm.jpg

 

[arman]

from memory, my engineering teacher couldn't even do this question, i'm going to a tute tomoz, so will ask him to do it

 

[hazza9]

Edited

http://img149.imageshack.us/img149/5822/estquestionm.jpg

How did u get that length? and how does it help our quest to find AB?

 

[bossleymaths]

sum of moments about Ra = 0 (CLOCKWISE POSITIVE)

-3 X RB + 12 X 30 + 3 X 10 = 0
RB =130 KN

for RAh you just sum all the horizontals the only there is 10kn so RAh = 10 KN

for RAv you do sum of vertical ie. 30 - Rb = Ra
30 -130 = -100 Kn (the negative means my direction is wrong so it is in fact 100 going downwards, i guess upwards)

for ab i will scan it cbf typing how

 

[tashisthebest]

Im using methods of joints in this.

using the reaction Rb n finding the angle at which the structure is at.
then just simple trig 2 find the hypotenuses, member AB.

I think another Question will help us

Describe the process and the advantages of powder forming?

 

[bossleymaths]

Im using methods of joints in this.

using the reaction Rb n finding the angle at which the structure is at.
then just simple trig 2 find the hypotenuses, member AB.

I think another Question will help us

Describe the process and the advantages of powder forming?

how do u no wat the angle is then it doesnt say to scale??

 

[tashisthebest]

how do u no wat the angle is then it doesnt say to scale??

its kinda hard to see.

total height of the bridge is 3 m n tha distance from Rb to the end of the bridge is 14m then using that get the angle under the bridge.

using alternative angles you get tha angle at the tip of the truss. then using sum of a triange = 180 then you find the angle tha you can use for the methods of joints.

 

[bossleymaths]

force in ab is 150 kn (rounded up from 149) and its in tension

 

[arman]

its kinda hard to see.

total height of the bridge is 3 m n tha distance from Rb to the end of the bridge is 14m then using that get the angle under the bridge.

using alternative angles you get tha angle at the tip of the truss. then using sum of a triange = 180 then you find the angle tha you can use for the methods of joints.

yeah that is probs way to do it, did u get an answer?


Powder Forming

Powder of a high melting temp. metal (eg: titanium) is made from its ore.
The powder is compacted under very high pressure to the desired shape. - this creates 'cold fusing/joining' of the particles to occur.
The metal is heated up (but not to melting temp) to allow for further joining of particles.

Advantages:
High dimensional accuracy
Eliminates machining and waste product
Can be used to make products out of otherwise hard to form materials (eg: titanium melts at much higher temp than a furnace or metal die can withstand)

 

[arman]

force in ab is 150 kn (rounded up from 149) and its in tension

ok, i will trust you with that one
...but i still want to see how my engineering teacher goes

 

[bossleymaths]

ok, i will trust you with that one
...but i still want to see how my engineering teacher goes

yeah no probs mate not sure if tension or compression but i just thought of it logically??

 

[arman]

Here's one from the 2003 HSC question 16 a) 4 marks

"The telecommunications industry uses copper and fibre optics for transmission of data. State a different application for each of these materials, and explain, in terms of their properties, why they are used for this application.

 

[bossleymaths]

Here's one from the 2003 HSC question 16 a) 4 marks

"The telecommunications industry uses copper and fibre optics for transmission of data. State a different application for each of these materials, and explain, in terms of their properties, why they are used for this application.

state: i would say telephone for copper and ummmm i would say internet/computer modem will use fibre optics (is this right i really dunno)

well copper used in telephone cuz its a good conductor of electricity, mass production is capable due to extensive use of telephone blah blah due to it being cheap

and fibre optics is used because it provides faster internet speeds without any corruption (unless specified) smooth data transmission

 

[bossleymaths]

hey arman wat nash r u btw, r u persian?? ur name sounds like it

 

[bossleymaths]

my question is how does a commutator work?