# Homework Help: Need help with heat transfe (conduction) questions!

1. Oct 2, 2012

### doctordiddy

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

A small pond has a layer of ice 1cm thick floating on its surface.

The air temperature is -10 C.

(a) What is the temperature of the liquid water just below the ice?

(b) Write the expression for the rate of heat transfer through the ice as a function of thickness of the ice?

(c) Write the expression for the rate of heat flow required to freeze the water?

(d) Find the initial rate in cm/hr at which ice is added to the layer.

(e) How long does it take for a 20cm layer to build up? .

2. Relevant equations

H= kA (Th-Tc)/L
H=dQ/dT

3. The attempt at a solution

For A) im not sure of the formula to use, I know only H = kA (Th-Tc)/L, but the question only provides L and Th and expects me to find Tc somehow.

For B) and C) i'm not really sure what it means by an expression (like dQ/dt = kA (Th-Tc)/L?)
would B) be like dH(L) = kA(Th-Tc)?

For D) i have the save problem as in question A) where I do not feel I have enough variables to solve for dQ/dt

i think i can probably solve for e) once I get the other parts.