What Would Be the Mass of an Iron-Dense Empire State Building?

[promeus]

If an object the size of the empire statbuilding had iron density,what would be ...

the mass of it?

The estimated volume of the empire state building is 37 million cubic feet,how could I calculate the mass of this solid object if it had a density of Iron(which would be 7870 kg/m³)?

 

[HallsofIvy]

Multiply the density by the volume.

 

[promeus]

So I converted the ft^3 to m^3 and I have 1.04 million m^3* 7870kg/m^3=8184800000 kg/m^3.Did I do this right or do I have to remove the kg/m^3?

 

[promeus]

Wow if I am correct is that over 8 billion kilograms of mass?

 

[promeus]

So here is a follow up question,how much energy would be required to propel this object at Mach 7 speeds?

 

[mrspeedybob]

1/2 mv²

m=mass in kg
v=speed in meters / second

That would be if the propulsion device was 100% efficient and there was no air resistance.