The velocity of a fluid particle at the center of a pipe is maximum. This is due to the concept of laminar flow.

Here's why:

* Laminar Flow: In laminar flow, fluid particles move in smooth, parallel layers. There's no mixing between layers. This typically occurs at low flow speeds.

* Friction and Shear Stress: The fluid particles near the pipe walls experience friction and shear stress. This slows them down.

* Velocity Profile: As you move away from the walls and towards the center, the friction and shear stress decrease. Consequently, the velocity of the fluid particles increases. The velocity profile across the pipe diameter is parabolic, with the maximum velocity occurring at the center.

Note: This is true for ideal laminar flow conditions. In reality, factors like turbulence and viscosity can affect the actual velocity profile.