class_docstr: A particle.
  
  Explanation
  ===========
  
  Particles have a non-zero mass and lack spatial extension; they take up no
  space.
  
  Values need to be supplied on initialization, but can be changed later.
  
  Parameters
  ==========
  
  name : str
      Name of particle
  point : Point
      A physics/mechanics Point which represents the position, velocity, and
      acceleration of this Particle
  mass : Sympifyable
      A SymPy expression representing the Particle's mass
  potential_energy : Sympifyable
      The potential energy of the Particle.
  
  Examples
  ========
  
  >>> from sympy.physics.mechanics import Particle, Point
  >>> from sympy import Symbol
  >>> po = Point('po')
  >>> m = Symbol('m')
  >>> pa = Particle('pa', po, m)
  >>> # Or you could change these later
  >>> pa.mass = m
  >>> pa.point = po
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docstr: Angular momentum of the particle about the point.
  
  Explanation
  ===========
  
  The angular momentum H, about some point O of a particle, P, is given
  by:
  
  ``H = cross(r, m * v)``
  
  where r is the position vector from point O to the particle P, m is
  the mass of the particle, and v is the velocity of the particle in
  the inertial frame, N.
  
  Parameters
  ==========
  
  point : Point
      The point about which angular momentum of the particle is desired.
  
  frame : ReferenceFrame
      The frame in which angular momentum is desired.
  
  Examples
  ========
  
  >>> from sympy.physics.mechanics import Particle, Point, ReferenceFrame
  >>> from sympy.physics.mechanics import dynamicsymbols
  >>> from sympy.physics.vector import init_vprinting
  >>> init_vprinting(pretty_print=False)
  >>> m, v, r = dynamicsymbols('m v r')
  >>> N = ReferenceFrame('N')
  >>> O = Point('O')
  >>> A = O.locatenew('A', r * N.x)
  >>> P = Particle('P', A, m)
  >>> P.point.set_vel(N, v * N.y)
  >>> P.angular_momentum(O, N)
  m*r*v*N.z
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code: def angular_momentum(self, point, frame):
      """Angular momentum of the particle about the point.
  
      Explanation
      ===========
  
      The angular momentum H, about some point O of a particle, P, is given
      by:
  
      ``H = cross(r, m * v)``
  
      where r is the position vector from point O to the particle P, m is
      the mass of the particle, and v is the velocity of the particle in
      the inertial frame, N.
  
      Parameters
      ==========
  
      point : Point
          The point about which angular momentum of the particle is desired.
  
      frame : ReferenceFrame
          The frame in which angular momentum is desired.
  
      Examples
      ========
  
      >>> from sympy.physics.mechanics import Particle, Point, ReferenceFrame
      >>> from sympy.physics.mechanics import dynamicsymbols
      >>> from sympy.physics.vector import init_vprinting
      >>> init_vprinting(pretty_print=False)
      >>> m, v, r = dynamicsymbols('m v r')
      >>> N = ReferenceFrame('N')
      >>> O = Point('O')
      >>> A = O.locatenew('A', r * N.x)
      >>> P = Particle('P', A, m)
      >>> P.point.set_vel(N, v * N.y)
      >>> P.angular_momentum(O, N)
      m*r*v*N.z
  
      """
  
      return cross(
          self.point.pos_from(point), self.mass * self.point.vel(frame)
      )
  
file_path: sympy/sympy/physics/mechanics/particle.py
imports: from sympy import S
  from sympy.physics.vector import cross, dot
  from sympy.physics.mechanics.body_base import BodyBase
  from sympy.physics.mechanics.inertia import inertia_of_point_mass
  from sympy.utilities.exceptions import sympy_deprecation_warning
label_desc: Use image node_id 3 for calling the Particle obj's underlying member method code with example usage: obj.angular_momentum(point, frame) and returns: cross