Physics

Stokes' Law Calculator

Find the drag force on a small sphere in viscous fluid.

Dynamic viscosity (Pa·s)

Sphere radius

Velocity

Calculated Output

Drag force (N) 0

Formula: F = 6π·μ·r·v

Step-by-Step Breakdown

1. Values used:

2. Dynamic viscosity = 0.001 Pa·s

3. Sphere radius = 0.5

4. Velocity = 0.02

6. Drag force = 0N

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The math behind it

F = 6π·μ·r·v, valid at low Reynolds number (smooth, creeping flow).

0.5 mm sphere at 0.02 m/s in water → about 1.88 × 10⁻⁹ N.

Where is it used?

Settling of fine particles, the falling-ball viscometer and aerosol physics.