A steel railroad track has a length of 39 m
when the temperature is 8°C.
What is the increase in the length of the
rail on a hot day when the temperature is
37°C? The linear expansion coefficient of
steel is 11 x 10 6 (°C) 1.
Answer in units of in.

Asquare isothermal chip is of width w=5 mm on a side and is mounted in a substrate such that its side and back surfaces are well insulated; the front surface is exposed to the flow of a coolant at tinf=15 °c. from reliability considerations, the chip temperature must not exceed t=85 °c. if the coolant is air and the corresponding convection coefficient is h=200 w/m2 x k, what is the maximum allowable "power" of the chip? if the coolant is a liquid for which h=3000 w/m2 x k, what is the maximum allowable power of the chip?