Calculating Heat Flow in Snow: 0°C & 37°C

AI Thread Summary
The discussion centers on calculating heat flow from a person with a body temperature of 37°C standing on snow at 0°C. The heat transfer occurs through the shoe soles, which have specific dimensions and thermal conductivity. The direction of heat flow is established as moving from the warmer body to the colder snow. The equation for heat conduction is provided, highlighting the need to consider temperature difference over the thickness of the shoe sole. Participants emphasize understanding the variables involved, particularly the temperature gradient and the sole's thickness, to solve the problem effectively.
Revolt
Messages
7
Reaction score
0

Homework Statement



a person with a body temp of 37 degrees stands on snow with a temp of 0 degrees
each of there shoes has a sole 1cm thick with an area of 300cm^2 and a 0.2 thermal conductivity
what is the magnitude and direction of heat flow

Homework Equations





The Attempt at a Solution



right well obviously the direction is into the ground, heat travels from hot to cold

now I am not sure if you need to calculate the volume of "sole" which the heat is being conducted through or not and that has me stumped as its the first hurdle at which I am clueless!
 
Physics news on Phys.org
What equation describes heat conduction?
 
dQ/dt = -kA dT/dx

if a is the cross sectional area of the sole of the shoe do you then not need the thickness of it ? ;s and dT/dx would be the rate of change of temperature, however I am unsure as to what the rate of change is as all your told is it changes from 37 to 0

ive hit a brick wall with this one !
 
Instead of dT/dx, write it as \Delta T/\Delta x. That's temperature difference over thickness.

For more, read Heat Conduction.
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...

Similar threads

Replies
12
Views
2K
Replies
4
Views
1K
Replies
13
Views
2K
Replies
6
Views
2K
Replies
3
Views
2K
Replies
2
Views
5K
Back
Top