Examination-Style Questions. Density of Material Questions (b)(i)(ii)

  • Thread starter Thread starter 54088
  • Start date Start date
  • Tags Tags
    Density Material
54088
Messages
13
Reaction score
0
i have done few simple questions by using p = m/v to calculate the mass, volume and density, but for this question, i don't know how to do it. Please help ^^"
(a) Define the density of a material.
>Density is the mass of the material per unit volume.

(b)Brass, an alloy of copper and zinc, consists of 70% BY VOLUME of copper and 30% BY VOLUME of zinc.
Density of Copper = 8.9 x 10^3kgm^-3
Density of Zinc = 7.1 x 10^3kgm^-3

(i)Determine the mass of copper and the mass of zinc required to make a rod of bras of volume 0.80 x 10^-3m^3
hmm..Cu = Mass x 70% x 8.9 x 10^3kgm^-3, Zn = Mass x 30% x 7.1 x 10^3kgm^-3...?
(ii)Calculate the density of brass.
I think i will know how to do this question if i know the answer for (i)... = =
 
Physics news on Phys.org
oh yeah, for question (ii), should i just add up the two densities and divided by 2?...
 
Can someone answer for me please...
 
54088 said:
oh yeah, for question (ii), should i just add up the two densities and divided by 2?...

If you're told that brass is made of 70% copper (by volume) and 30% zinc (also by volume), why would you expect the density of brass to be made of equal portions?
 
jdwood983 said:
If you're told that brass is made of 70% copper (by volume) and 30% zinc (also by volume), why would you expect the density of brass to be made of equal portions?

so what should i do?
 
Not to sound cryptic, but I'll answer your question with another question: If you had to make a piece of copper that that had a volume of 0.8\times10^{-3} \mathrm{m^3}, how would you go about finding the mass required? And if the previous volume were to be made of only zinc, what would its mass be?
 

Thread 'Initial conditions for orbits around a wormhole'

Hi, I had an exam and I completely messed up a problem. Especially one part which was necessary for the rest of the problem. Basically, I have a wormhole metric: $$(ds)^2 = -(dt)^2 + (dr)^2 + (r^2 + b^2)( (d\theta)^2 + sin^2 \theta (d\phi)^2 )$$ Where ##b=1## with an orbit only in the equatorial plane. We also know from the question that the orbit must satisfy this relationship: $$\varepsilon = \frac{1}{2} (\frac{dr}{d\tau})^2 + V_{eff}(r)$$ Ultimately, I was tasked to find the initial...
View full post »

Thread 'Please tell me where I am going wrong in this integral'

##|\Psi|^2=\frac{1}{\sqrt{\pi b^2}}\exp(\frac{-(x-x_0)^2}{b^2}).## ##\braket{x}=\frac{1}{\sqrt{\pi b^2}}\int_{-\infty}^{\infty}dx\,x\exp(-\frac{(x-x_0)^2}{b^2}).## ##y=x-x_0 \quad x=y+x_0 \quad dy=dx.## The boundaries remain infinite, I believe. ##\frac{1}{\sqrt{\pi b^2}}\int_{-\infty}^{\infty}dy(y+x_0)\exp(\frac{-y^2}{b^2}).## ##\frac{2}{\sqrt{\pi b^2}}\int_0^{\infty}dy\,y\exp(\frac{-y^2}{b^2})+\frac{2x_0}{\sqrt{\pi b^2}}\int_0^{\infty}dy\,\exp(-\frac{y^2}{b^2}).## I then resolved the two...
View full post »

Similar threads

Question about this unusual galvanic bath
Replies
5
Views
2K
Radiant heat transfer and specific heat
Replies
8
Views
2K
My modernization of Definition I in Newton's Principia
Replies
14
Views
1K
Energy density of the cosmological constant units question
Replies
1
Views
2K
What is the density of pure chromium in g cm^-3?
Replies
44
Views
4K
Solve Archimedes Problem: Find Crown's Density
Replies
4
Views
2K
How can I determine the shape of an oldie acid molecule?
Replies
1
Views
1K
I What is the density of hydrogen atoms in the Universe?
Replies
3
Views
2K
Confusion on product rule for mass of differential volume element
Replies
4
Views
2K
I Extremely strange consequence of the speed of heat value
Replies
19
Views
2K

Hot Threads

Recent Insights

Back
Top