Final answer:
The importance of r1 in determining when dN1/dt equals zero depends on the physical context, which is not provided in the question. r1 could influence dN1/dt in some situations, while in others, particularly in physics, external forces rather than arbitrary constants like r1 govern the rate of change of a quantity with time.
Step-by-step explanation:
The question seems to be missing context or is incorrectly formulated, as r1 and dN1/dt are not defined within the question or provided references. Generally, in physics, dN1/dt would represent the rate of change of some quantity N1 with respect to time. Whether r1 determines when this rate of change equals zero would depend on the specific physical context and how r1 relates to N1.
For example, if we are discussing growth rates in a biological population, r1 might represent some rate constant and dN1/dt = 0 could indicate a steady-state population where births balance deaths, and thus r1 could be a factor in determining that condition.
If we are discussing a physics problem and dN1/dt represents the rate of change of momentum, then no, r1 does not determine when this rate is zero because momentum change is dictated by external forces regardless of parameters like r1, assuming r1 doesn't represent a force or related parameter in this context.