Friday
October 24, 2014

Homework Help: physics

Posted by Lydia on Thursday, February 21, 2008 at 8:17pm.

At a picnic, a Styrofoam cup contains lemonade and ice at 0 degree C. The thickness of the cup is 2.0*10^-3m, and the area is 0.016 m^2. The temperature at the outside surface of the cup is 35 degree C. The latent heat of fusion for ice is 3.35*10^5 J/kg. What mass of ice melts in one hour?

I had posted this question several hours ago, and someone gave me such solution:
You need the heat transfer coefficient of styrofoam. It is about .01 watts meters/deg

call area of foam A = .016 m^2
call temperature difference across styrofoam = 35 - 0 = 35 deg C
call thickness of foam t = 2*10^-3 m
then heat gained through foam = (k A/t)((35-0)
heat gain rate watts = (.01*.016/.002)(35)

That watts * time in seconds = Joules
so that times 3600 = Joules gained to melt ice in one hour. Now kg melted = Joules gained/ heat of fusion in Joules/ kilogram

However, I don't quite get the last part, can someone please explain? Thanks!

Answer this Question

First Name:
School Subject:
Answer:

Related Questions

PHYSICS!!!HELP!! - At a picnic, a Styrofoam cup contains lemonade ...
physics - At a picnic, a Styrofoam cup contains lemonade and ice at 0 degree C. ...
Physic - Assume all temperatures to be exact. An aluminum spoon at 84 degree C ...
physics - A 29 g ice cube at 0.0C is added to 110 g of water in a 62 g iron cup...
math - people flock to andys lemonade stand because each cup of lemonade is only...
Science - Imagine you made a gallon pitcher of lemonade for your family picnic....
Science (Asap) - Imagine you made a gallon pitcher of lemonade for your family ...
physics - A Styrofoam box has a surface area of 0.78 m2 and a wall thickness of ...
physics - A Styrofoam box has a surface area of 0.75 m2 and a wall thickness of ...
MATH - Carolyn and Kim are selling lemonade this summer.  It costs $0.10...

Search
Members