Grade 10 math problem?

Comments

• anonymous

  May 2021

  copper block volume ???

  your question is WRONG

  lol
• something-clever

  May 2021

  You need more information. Are you certain that the mass of copper isn't given in the problem? The issue is, if we don't know how much copper is being used, the length of the copper pipe cannot be computed.

  Example: Let's say that the mass of copper used is 2g

  The density of copper is 8.96 g·cm−3 which I found here:

  http://en.wikipedia.org/wiki/Copper

  Then we can compute the volume of the copper block that is being used by dividing the mass by its density:

  V = m/p, V = volume, m = mass, p = density. Using our values:

  V = 2g / 8.96 g*cm^-3

  V = 0.2232 cm^3, converting this into mm^3

  V = 1000*0.223214

  V = 223.214 mm^3, and this is the volume of copper we have to make our pipe.

  Now the volume of a cylindrical pipe is:

  V = π*r1^2*L - π*r2^2*L

  V = volume, r1 = outer radius, r2 = inner radius, L = length, doing a bit of factoring:

  V = π*L*(r1^2 - r2^2)

  The problem gives measurements in terms of diameter, we cut these in half to get the radii.

  r1 = 7mm, r2 = 5mm

  and we know our volume V = 223.214 mm^3 from our previous calculation. We can plug these into our equation:

  223.214 = π*L*(7^2 - 5^2)

  223.214 = π*L*(49 - 25)

  223.214 = π*L*(24), solving for L

  (223.214) / (π*24) = L

  So for this example:

  L = (223.214) / (π*24)

  L = 2.9605 mm

  So a cylindrical copper pipe made out of 2 grams of copper with the dimensions given in the problem would have a length of 2.9605 mm. So if you know the mass of the copper in the problem, you are able to solve it.
• raj-k

  May 2021

  Let Volume of the block= V

  Volume of holloe pipe =π(R²−r²)×x

  Where R = Outside Radius

  r = inner radius

  and x = Length of the tube

  Equate V=π(R²−r²)×x

  Substitute values and get x
• wedisinghe

  May 2021

  The volume is required.