physics problem....plz help me?

Question

Grains of fine sand are approximately spheres with an average radius of 50 μm and are made of silicon dioxide. A solid cube of this material with a volume of 1 m3 has a mass of 2600 kg.

a)What mass of sand grains would have a total surface area (the total area of all the individual grains) equal to the surface area of a cube 1 meters on an edge?
mtotal = ______kg.

Answer 1

I got about a half kg
But I am confused by the line "A solid cube of this material with a volume..." when they say volume do they mean volume of the spheres only or with the open spaces in between (I used the second interpretation)

1. Convert 50 um into m 50 x 10^(-6)
2. Plug into the equation to get surface area of a single sphere (1x10^(-8)(Pi)) 4(Pi)r^2
3. Divide 6 (the surface area of the 1by1by1 cube) by the surface area of one sphere to find out how many spheres you need (190,985,931)
4. To find the weight of a sphere multiply 50 um by 2 (converts radius into diameter) (100um)
5. Convert 100 um into m (1x10^(-4))
6. Take 1 (the length of the side of the cube) and divid it by (1x10^(-4)) to get 10,000
That number is the amount of spheres on one edge of the cube.
6. Cube 10,000 to find the total amount of spheres in the cube (1x10^12)
7. Take 2600 and divide it by (1x10^12) to find the weight of one sphere (2.6x10^(-9))
8. Multiply that by the total number of spheres required (190,985,931) to get about .5kg

I'm not positive about the way the question is worded, but if this isn't correct hopefully it at least pointed you in the right direction.

Answer 2

What's the problem? Calculate the surface area of one spherical grain of sand. Divide that into 6 meters and that's the number of grains of sand you need. Assume that every grain ocupies a 'cube' that is 100 µm square and that they are 'layered in to the 1 m cube. That tells you how many grains of sand make up 2600 kg. Multiply 2600 by the number of grains of sand, multiply that by the number of grains it takes to make 6 meters of surface area and that's the mass.

Go do it.


Doug

Answer 3

in basic terms extra physics jargon ... i'm no longer even specific if it fairly is right anymore ... Photons and gluons are strictly massless. they're the gauge fields of unbroken symmetries (no longer purely like the vulnerable vector bosons). because of the solid tension and the self-interactions of the gluons (the solid tension originates from a non-Abelian group -- so there is self interplay between the gauge fields -- the gauge fields themselves are charged), there could be gluon condensation and the condensation looks enormous. As they're massless, they do no longer at as quickly as work together with Higgs boson on the tree-point. At bigger-loop ranges, there are interactions because of the fact which you could have each sort of digital debris (i.e. debris which at the instant are not 'on-shell'). the comparable probable is going for the interactions with gravitons (the particle interpretation of the gravitational field). Photons curve around super bodies. Photons can no longer get away black holes while they're interior the form horizon of the black holes. even nonetheless, those 2 issues are fairly autonomous, except the curvature of the photon trajectory is brought on by ability of the black hollow.

Answer 4

r u in like advanced physics???