Unformatted text preview: axis. its central mg about rigid body rotat' isa The ﬂywheel ' n
0 Model wmax = 1200 rpm ZC = 0.75 m R = 250 kg
(a) The radius of the ﬂywheel M about the a . 1118 The moment of 250 kg. isM= S mass it R =0.75 m and 18 on is that of a disk tati 2 2
711 rad/s 0 ) 31kgm 2 =70 éaso kg)(0.75 my
/I = (50 N m)/(70.31 kg m as follows
rnet Ia=>a lMR2
2 alculated I d
t is c
1119 on The angular accelerati 13—23 fa Rigid Body
— 0 s) (t, [On 0 Rotat'
= 0 rad/s + 0.711 rad/s2 4O irrad/s
=5 tI = 177 s gives i 1200 rpm for angular veloc
_ t0 ) = i
2
were (70.31 kg m2)(407trad/s)2 = 5.55 x105 J 100,2 1 2
energy del 407: rad ls. (0,”,me 88.85 rad/s = 70.31 kg m2 ”/2 =1.39X105 W = 139 kW 3
). wmuemgy = a), (from part (21)) 2 (5.55 ><105 dun
At wmll energy — (”half energy
3 whalf energy time i terval
= ,(
1
5 Km A_w
At .85 rad/s):1300 N m —88
2s 1' ___ (70.31 kg m2)(40 Irrad/s Mi... (b) The energy stored in the ﬂywheel is rotational kinetic energy o 1
r. r v. \
.1 f ( M m
5 .N E O n a K = I m
5 M M. .s o + M __ M
3 .I. 0 M (J. 0 r. T 2m
1 V S a a w W m
. w. __ .h = I
. e 1 .m i .1 _ 2
.w w r m
m. e .s
m W = a
e M. T M
.m e e .n
k g s m
a u t
e r a b
.m e C 0
V C e
We A B b m
3., at ,: usual helhﬂﬂ. «.8 . .1 \II n
,1 4/ «M85 . Y , :3 n S )
Mg M MM 1.. 33:. U k m w m
a. 3 T n .1. in . a“. 0M aﬁymewwwm?“ t» mmbn Mimemaswm... My .35, 32%....
ﬁwiwttmwﬁmhﬁuwiwmwrwfei Wmeiwhiﬁxmeanwwwwwixm» \mevhmtmlwf . . . M.) M .w aerMMMM. ...
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 Winter '08
 Susskind,L
 Physics, mechanics

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