Lecture51 : Applications of Divergence theorem [Section 51.2]
when is a constant and represents the temperature of the body at a
point at time . If the flow of heat is 'steady', i.e., does not depend upon temperature, then i.e., the temperature of steady heat flow is a
harmonic function.
(ii)
Consider the gravitational force on a particle of mass at any point due to a mass at a fixed
is a constant and 
represents the temperature of the body at a
point 
at time 
. If the flow of heat is 'steady', i.e., 
does not depend upon temperature, then 
i.e., the temperature of steady heat flow is a
harmonic function. 
of mass 
at any point 
due to a mass 
at a fixed
The gravitation force is
