Why melting point of fe in blast furnace is lower than ellingham?

Because they are different oxides.

Explanation:

In both processes they are involve Iron Oxides, but in the case of Ellingham diagrams, it is consider the Iron in combination with oxygen to form FeO, so the melting point is around 1600  ºC. In the case of blast furnace, the Fe that is present in the ores, are primary the hematite (Fe2O3) and the magnetite (Fe3O4).

a: 45.9 meters

b: 4.29 seconds

step-by-step explanation:

a: h(t)=1/2(-9.8)(3)^2+0(3)+90

h(t)=-4.9(3)^2+90

h(t)=-44.1+90

h(t)=45.9 meters

b: 0=1/2(-9.8)(t^2)+0t+90

0=-4.9t^2+90

-90=-4.9t^2

18.37=t^2

t=4.29 seconds

in the second question, the numbers aren't exact, but they're a close approximation.