Next question A person coughs when a foreign object is in the windpipe. The velocity of the cough depends on the size of the object. Suppose a person has a windpipe with a 20-mm radius. If a foreign object has a radius r, in millimeters, then the velocity V, in millimeters/second, needed to remove the object by a cough is given by the following equation, where k is some positive constant. For what size object is the maximum velocity needed to remove the object? V(n) = k (2012 - 13) , Osrs 20 An object that has a radius of will need maximum velocity to remove it. (Type an integer or a simplified fraction.)