In our world with our physics, could Superman REALLY dig a hole through rock simply by spinning really fast? Remember, there is dust and grit that rock, brick, cement, etc. turns into. Would the dust fly out by the acceleration? How fast would the air be replenished? Would he have to take a deep breath to blow out during the spin to clear the dust? Or maybe fly down at superspeed to produce either a funnel of air, enough momentum, or both?

(I wanted to be an engineer but failed both physics and calculus so I'm asking for help with this idea)

He doesn't even need to breathe in the comics.

Not our world, the comic world. Different rules.

Think of his feet as a diamond-tipped drill :)

Ya his feet are much harder than anything on earth so it works like a regular drill,I'd think. What happens to the dust produced by a drill? I guess the same happens here but it's a 6 foot drill.

Apparently his nails are harder than diamond. It's not that much of a stretch to suggest that his feet could do the same.

Also, comics.