We have the next information
r=radius=142m
k=coeffcient of friction=1.07
The maximum frictional force is
[tex]F=\text{kmg}[/tex]where F is the frictional force, k is the coefficient of friction, m is the mass and g is the gravity.
Also for the centripetal force we have the next formula
[tex]F=\frac{mv^2}{r}[/tex]where F is the force, m is the mass , v the speed and r is the radius
we have an equivalence between the two formulas
[tex]\frac{mv^2}{r}=\text{kmg}[/tex]then we simplify and we isolate the speed
[tex]v=\sqrt[]{\text{krg}}[/tex]we substitute the values
[tex]v=\sqrt[]{(1.07)(142)(9.8)}[/tex]the maximum speed is
[tex]v=38.6\text{ m/s}[/tex]ANSWER
v=38.6 m/s