What are the Function of stand unit

It is called the unit function because it is the identity element for Dirichlet convolution. It may be described as the "indicator function of 1" within the set of positive integers. It is also written as u(n) (not to be confused with μ(n), which generally denotes the Möbius function).

double the distance = divide strength by 4

the correct answer is "inertia"