# Rotation of a Bicycle Wheel

Circular motion at a constant velocity requires a net force toward the center of rotation.

If I stand a bicycle on its seat, wheels upwards and spin the wheels with my hands, they start rotating. Where is the netforce toward the center of the wheel coming from. Is there one in this situation?

Thank you.

• The wheel's structure (spokes, rim, etc.) provide the necessary force – user1936752 Nov 24 '18 at 23:07

The radial force acts outward. The tangential force acts at a $$90^o$$ angle to the line of action. The line of action is the imaginary line through which your force acts. It is always connected to the axis of rotation. The vector sum of these forces is your net force.
So in summary there is a net inward force, it's just not as applicable in rigid-body rotation. Your net inward force (centripetal force) simply acts in the direction of change in velocity. This $$\Delta v$$ is inward along the circular path.