Which best describes the differences between how ptolemy and copernicus described the solar system?
a.
ptolemy saw the sun at the center of the solar system, while copernicus saw the earth as the center.
b.
ptolemy saw the earth at the center of the solar system, while copernicus saw the moon as the center.
c.
ptolemy had a heliocentric view of the universe, while copernicus had a geocentric view of the solar system.
d.
ptolemy saw the earth at the center of the solar system, while copernicus saw the sun as the center.

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?