<u><em>Answer:</em></u>
<u><em>god knows.</em></u>
Explanation:
Because the coefficient of friction depends on the surface
Answer:

Explanation:
We know that when we don't have air friction on a free fall the mechanical energy (I will symbololize it with ME) is equal everywhere. So we have:

where me(1) is mechanical energy while on h=10m
and me(2) is mechanical energy while on the ground
Ek(1) + DynamicE(1) = Ek(2) + DynamicE(2)
Ek(1) is equal to zero since an object that has reached its max height has a speed equal to zero.
DynamicE(2) is equal to zero since it's touching the ground
Using that info we have

we divide both sides of the equation with mass to make the math easier.

Answer:
12000 miles per hour
Explanation:
If skid Marx went from zero to 10 miles in 3 seconds the his speed would have been 12000 miles per hour.