RigidBodyPendulumDynamicsFBD.html  (MotionGenesis input/output).
```   (1) % MotionGenesis file:  RigidBodyPendulumDynamicsFBD.txt
(3) %----------------------------------------------------------------
(4) NewtonianFrame  N            % Earth.
(5) RigidBody       A            % Rod.
(6) %----------------------------------------------------------------
(7) Variable   theta''           % Angle and 1st/2nd time-derivatives.
(8) Constant   g = 9.8 m/s^2
(9) Constant   L = 7.5 cm
(10) A.SetMassInertia( m = 10 grams,  IAx,  IAy,  I = 50 g*cm^2 )
(11) %----------------------------------------------------------------
(12) %       Rotational and translational kinematics.
(13) A.RotateZ( N, theta )
-> (14) A_N = [cos(theta), sin(theta), 0;  -sin(theta), cos(theta), 0;  0, 0, 1]
-> (15) w_A_N> = theta'*Az>
-> (16) alf_A_N> = theta''*Az>

(17) Acm.Translate( No, -L*Ay> )
-> (18) p_No_Acm> = -L*Ay>
-> (19) v_Acm_N> = L*theta'*Ax>
-> (20) a_Acm_N> = L*theta''*Ax> + L*theta'^2*Ay>

(21) %----------------------------------------------------------------
-> (24) Force_Acm> = -m*g*Ny>

(25) %----------------------------------------------------------------
(26) %       Rotational equation of motion.
(27) Dynamics = Dot(  Nz>,   A.GetDynamics(No)  )
-> (28) Dynamics = m*g*L*sin(theta) + I*theta'' + m*L^2*theta''

(29) Solve( Dynamics,  theta'' )
-> (30) theta'' = -m*g*L*sin(theta)/(I+m*L^2)

(31) %---------------------------------------------------------------
(32) %       Check conservation of kinetic and potential energy.
(33) KE = System.GetKineticEnergy()
-> (34) KE = 0.5*(I+m*L^2)*theta'^2

(35) PE = System.GetForceGravityPotentialEnergy( -g*Ny>, No )
-> (36) PE = -m*g*L*cos(theta)

(37) MechanicalEnergy = KE + PE
-> (38) MechanicalEnergy = PE + KE

(39) %----------------------------------------------------------------
(40) %       Integration parameters and initial values.
(41) Input  tFinal = 4 sec,  tStep  = 0.02 sec,  absError = 1.0E-07
(42) Input  theta = 90 deg,  theta' = 0.0 rad/sec
(43) %----------------------------------------------------------------
(44) %       List output quantities and solve ODEs.
(45) Output  t seconds,  theta degrees,  MechanicalEnergy Joules
(46) ODE()

(47) %----------------------------------------------------------------
```
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