Equations of Motion

Normal and Tangential Coordinates

For an object moving along a path which is curved the components of the forces can be shown in the tangential and normal directions.

Tangential direction: ∑ Ft = mat Acts(points) tangent to the path of the object.
Normal direction: ∑ Fn = man Acts(points) toward the center of curvature of the path.
- an is equal to (v^2 / ρ) where ρ is the radius of curvature(distance from center to point on path) and v is the velocity.


Cylindrical (Polar) Coordinates

These coordinates are used when dealing with angular motion and knowing the radial line for the path of the object.

∑ Fr = mar Radial line
∑ Fθ = maθ Angle measured from the radial line


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