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pyfreebody

Construct free-body diagrams with a few lines of code.

pip install pyfreebody
View source →

Every diagram below was rendered by the library itself, as inline SVG. Each to_svg() call is shown next to its output.

A block with four forces

10 kgFgFnFaFfGravity = 98.1 NNormal = 98.1 NApplied = 50 NFriction = 30 Nnet = 20.0 NBlock
fb = Freebody("Block", mass=10)
fb.addForce("Gravity", 98.1, Direction.down)
fb.addForce("Normal", 98.1, Direction.up)
fb.addForce("Applied", 50, Direction.right)
fb.addForce("Friction", 30, Direction.left)
fb.to_svg(show_net=True)

Hanging mass (equilibrium)

5 kgGravity = 49.050000000000004 NTension = 49.05 NHanging mass
fb = Freebody("Hanging mass", mass=5, legend=LegendType.arrow)
fb.add_weight()                 # gravity = m*g, down
fb.addForce("Tension", 49.05, Direction.up)
fb.to_svg()

Resultant of two forces

1 kgFeFnEast = 3 NNorth = 4 Nnet = 5.0 NResultant (3-4-5)
fb = Freebody("Resultant (3-4-5)", mass=1)
fb.addForce("East", 3, Direction.right)
fb.addForce("North", 4, Direction.up)
fb.net_magnitude()   # -> 5.0
fb.to_svg(show_net=True)

Crate on an inclined plane

12 kgWeight = 117.7 NNormal = 102 NFriction = 58 NCrate on ramp
fb = Freebody("Crate on ramp", mass=12,
              sysType=SystemType.inclined_plane, incline=0.52)
fb.addForce("Weight", 117.7, Direction.down)
fb.addForce("Normal", 102, Direction.degrees(120))
fb.addForce("Friction", 58, Direction.degrees(30))
fb.to_svg()

Angled pull on a box

8 kgFgFnFpGravity = 78.48 NNormal = 78.5 NPull = 60 NAngled pull
fb = Freebody("Angled pull", mass=8)
fb.add_weight()
fb.addForce("Normal", 78.5, Direction.up)
fb.addForce("Pull", 60, Direction.degrees(35))
fb.to_svg()