**EXAMPLE 3: ****Work-energy relation for a rigid body**

The
uniform bar of mass *m* and length *l* is released from rest in the
horizontal position. Calculate the angular velocity of the bar as a function
of _{}.

**Solution:**

Force
analysis: _{} do no work and mg is
conservative

_{}

_{}

_{}

_{}

_{}

_{}

Substitution
into (1) gives

_{}

_{}