Unformatted text preview: A disk rotates about its central axis starting from rest and accelerates with constant angular acceleration. At one time it is rotating at 9.6 revls;
92 revolutions later, its angular speed is 22 revi's. Calculate {a} the angular acceleration (revis‘2), {b} the time required to complete the 92
revolutions, {c} the time required to reach the 9.6 revr's angular speed, and {d} the number of revolutions from rest until the time the disk
reaches the 9.6 revls angular speed. Given
Initial angular velocity uJa : 9.3 revisec = 9.6*2*pi radianfsec = 33.32 radl's Final ang. velocity l—lul :1 22 revfs = 22*2*pi radfs = 138.23 radfs
Angular displacement G I 92 rev = 92*2*pi radians = 5?8.1 rad. ,,_ '1
muse lo : UJu +1016 A 1. Angular acceleration
Thus, (13823)"? = (68.32)”? + 2*alpha*5?8.1 Or alpha = 13.38 radfs“2 = 2.13 revfs“2 (b)Use VJ:LJ*J'{J_l’D<t Or i a ULL‘JEL 13323—3332
04 13.33
2 ﬂ'2 5.82 sec
13.33 (c)oJa=U / l 3 _ Ct . lo MW (5 :6032 radils t=4.508221226 sec (d) Ldo '— O
t_ :4533 s
and —_ 13.33 radfs“2 ’l_
U53 (5‘: lJ—lrJJDJfliﬁt
: O—l— Jidf I a
2. . 711333 (453332 = M
1 135.95 _§______ iii ...
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 Winter '01
 Bill
 Physics

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