Kinematics of a Moving Point

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A point follows a path, showing its acceleration, velocity and jerk vectors attached. The path is equally defined by these vectors provided integration constants are defined. The accelerated circular motion shows why spoked wheels may have leading and trailing spokes.

Contributed by: Paul van der Schaaf (March 2011)
Open content licensed under CC BY-NC-SA



In particular, the accelerated circular motion shows that when the particle's speed is increasing, the acceleration vector rotates to lead the radius, and when the speed is decreasing, the acceleration vector rotates to trail the radius. Newton's second law states that the acceleration vector is collinear with the force vector. This is why a bicycle wheel's spoke pattern has leading spokes to efficiently transmit the pedaling torque to the wheel rim, and similarly, trailing spokes to efficiently transmit the braking torque to the rim (for wheels where the braking torque works through the hub, such as for wheels fitted with disc and coaster brakes).

For more information see Sheldon Brown's Wheel Building.

The point following an Archimedean spiral does so at a constant speed.

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