The maximum speed around a level curve is 30.0 km/h. What is the maximum speed around a curve with twice the?

Question

radius? ( Assume all others factors remain unchanged).

Answer 1

The equation that applies here is centripidal acceleration.
namely,

F = m*(v^2)/r

The force is the limiting factor. To much force and the tires can't grip the road, so set the forces equal. We will use 2r for the "twice the radius" factor and v2 to represent the second velocity.

m*(v^2)/r = m*(v2^2)/2r

notice that the m and r variables can be directly cancelled leaving you with,

v^2=(v2^2)/2

So v2^2 = 2v^2

Take the square root:

v2 = sqrt(2)*v

v2 = 42.43 km/h
..

Answer 2

V1=(urg)^1/2
V2=(u2rg)^1/2
v1/v2=1/{(2)^1/2}
30*1.414=v2
v2=42.42