A thin metal cylinder of length L and radius R is coaxial with a thin metal cylindrical shell of length L and larger radius Rs. The space between the cylinders is filled with a material with resistivity p. A battery is connected to the two conducting pieces such that there is a potential difference AV between them which causes a current I to flow radially from the inner cylinder to the outer one. Find an expression for the resistance R of this device. (Remember that the expression R=PL/ A was derived under specific assumptions and doesn't apply here)

Newton's law of cooling states that the rate of change in the temperature t(t) of a body is proportional to the difference between the temperature of the medium m(t) and the temperature of the body. that is, startfraction dt over dt endfraction equals upper k left bracket upper m left parenthesis t right parenthesis minus upper t left parenthesis t right parenthesis right bracket , where k is a constant. let kequals0.04 left parenthesis min right parenthesis superscript negative 1 and the temperature of the medium be constant, m(t) font size decreased by 3 equivalent font size decreased by 3 294 kelvins. if the body is initially at 369 kelvins, use euler's method with hequals0.1 min to approximate the temperature of the body after (a) 30 minutes and (b) 60 minutes.