Spiderman destroys a stone slab in a microsecond
Original scan
Now in order for me to calculate this I will use the wind line thing or what ever it's called (which implies Spider-Man moved his foot from there to the other side)
The average human foot is 26.3 Cm
26.3/1.6 = X/6
157.8 = 6X
157.8/6 = X
98.63 Cm
Now that we have solved half of it, I'll multiple it by two
98.63 x 2
197.266 Cm = 1.97266 Meters
1.97266 Meters/1 Microsecond
1,972,660 m/s
Mach 5797
According to Antonifer this is a impossible for human legs to do so here is Antonifer calculation, which is the correct one
2*pi*(160/360)*1.78*(23.2 +24.7 + 4.25)/100 = 2.59 m; so speed would be 2590000 m/s or Mach 7535.8