Kinematics viscosity of the oil
The kinematic viscosity of a fluid is a measure of its resistance to flow under the influence of gravity. It is defined as the ratio of the dynamic viscosity to the density of the fluid. In this case, the kinematic viscosity of the oil is given as 0.25 stokes.

Flow through a pipe
When a fluid flows through a pipe, it experiences various forces and pressure drops. The flow can be categorized as laminar or turbulent, depending on the fluid velocity and the pipe's characteristics. In laminar flow, the fluid particles move in parallel layers with minimal mixing, while in turbulent flow, the fluid particles move in a chaotic and irregular manner.

Critical flow
Critical flow occurs when the fluid velocity reaches a specific value, known as the critical velocity or the critical flow rate. At this velocity, the flow transitions from laminar to turbulent. The critical velocity depends on various factors such as the fluid properties, pipe diameter, and kinematic viscosity.

Determining the critical velocity
To determine the critical velocity in this scenario, we can use the Reynolds number. The Reynolds number (Re) is a dimensionless quantity that characterizes the flow regime. It is calculated as the product of the fluid velocity, pipe diameter, and the kinematic viscosity, divided by the dynamic viscosity.

Re = (velocity x diameter x kinematic viscosity) / dynamic viscosity

Since the question does not provide the dynamic viscosity of the oil, we cannot directly calculate the critical velocity. However, we can still determine the critical flow condition based on the given information.

Flow condition
If the flow is critical, it means that the fluid is transitioning from laminar to turbulent. In this case, the velocity at the critical flow condition can be estimated to be around 0.25 times the speed of sound in the fluid.

Conclusion
To summarize, the critical velocity of the oil flowing through a pipe with a diameter of 10 centimeters and a kinematic viscosity of 0.25 stokes cannot be directly determined without knowing the dynamic viscosity of the oil. However, the critical flow condition indicates that the velocity is around 0.25 times the speed of sound in the fluid.