1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Word problem-I would like to check my procedure

  1. Oct 15, 2009 #1
    word problem-Please help me to check my procedure

    1. The problem statement, all variables and given/known data

    A cubical ice block is melting at a rate that relates to its surface area. Set up an equation for the volume of a cube, C, in terms of its surface area, S.

    2. Relevant equations

    C=x^3
    S=6x^2

    3. The attempt at a solution


    let length of the side of the cube:x
    dC/dx=3x^2 dS/dx=12x dC/dS=x/4
    Now what should I do? I think I did pretty well untill now. How should I use this information for getting the answer? Or dC/dS(which is x/4) is the final answer?
     
    Last edited: Oct 15, 2009
  2. jcsd
  3. Oct 15, 2009 #2

    symbolipoint

    User Avatar
    Homework Helper
    Education Advisor
    Gold Member

    You are almost half-way there, and this is not a calculus problem.

    Work with S and find a formula for x.
     
  4. Oct 15, 2009 #3
    Thank you. But work with S? Would you mind if I want more specific explanation from you? Sorry, cause I am not very good at math, interpreting word problems.
     
  5. Oct 15, 2009 #4

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    The problem said "Set up an equation for the volume of a cube, C, in terms of its surface area, S". That's why you need to "work with S".
    You have [itex]C= x^3[/itex]. You also know that [/itex]S= 6x^2[/itex].

    Solve [itex]S= 6x^2[/itex] for x (which is a length and so positive) and replace the "x" in [itex]C= x^3[/itex] with that/
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Word problem-I would like to check my procedure
Loading...