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Physical and Chemical Data 367

Figure 5.3 Determination of average angular
speed.

Angular frequency

Let M be an object that is rotating about a fixed axis L at a
constant rate. Let f be the number of complete rotationð that
occur per second. Then the angular frequencð (in radianð per
secon™ is denoted , and is given by:

2 f

Angular acceleration

Let M be an object that is rotating about a fixed axis L at a rate
that changeð uniformly over a time interval starting at time t
1
and ending at time t (t t secondð late?˜ Let the angular
2
2
1
speed (in radianð per secon™ at time t be , and let the an-
1
1
gular speed at time t be . Then the angular acceleration (in
2
2
radianð per second square™ during the time interval [ t ,t ]is
1
2
denoted
, and is given by:

( )/(t t )
2 1 2 1
MomenŁ of inertia
Let an object M be comprised of smaller mass componentð m ,
1
m , m ,..., m (in kilogram0. Suppose these componentð are
2
n
3