DYNAMICS OF ROTATIONAL MOTION
ANGULAR MOMENTUM; OBJECTS ROTATING AT FIXED POINTS
Angular momentum, L= iw
L is conserved when there is no external torque
w change when moment of inertia change
Rotational analog of Newton's 2nd Law 
VECTOR CROSS PRODUCT; TORQUE AS VECTOR
a vector
Direction cross product defined by right-hand rule
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Can also be written in determinant form
ANGULAR MOMENTUM OF A PARTICLE
ANGULAR MOMENTUM & TORQUE FOR A SYSTEM PARTICLES
The angular momentum of a system of particles can
change only if there is an external torque
ANGULAR MOMENTUM & TORQUE
When the system is rotationally imbalanced :
L and w is not in the same direction
A torque is required to keep the same picture
CONSERVATION OF ANGULAR MOMENTUM
The total angular momentum of a system remains constant if the net external torque acting on the system is zero