0 5 10 15 20 25 30 0 2 4 6 Time (s) X (m) 8
0 5 10 15 20 25 30 0 2 4 6 Time (s) X (m) 8
0 5 10 15 20 25 30 0 2 4 6 Time (s) X (m) 8
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P211 Final Sample 1<br />
13) Each of the three helicopter rotor blades shown in the figure below is 5.<strong>20</strong> m long and has a<br />
mass of 2<strong>10</strong> kg. The rotor is rotating at <strong>20</strong>0 rev/min (<strong>20</strong>.94 rad/s).<br />
If each blade can be considered to be a thin uniform rod, what is the kinetic energy of rotation of the<br />
entire blade assembly?<br />
A) 4.<strong>30</strong> × <strong>10</strong> 4 J B) 1.29 × <strong>10</strong> 5 J C) 6.55 × <strong>10</strong> 5 J<br />
D) 1.24 × <strong>10</strong> 6 J E) 3.92 × <strong>10</strong> 6 J<br />
14) A merry-go-round of radius R = 2 m has a moment of inertia I = <strong>20</strong>0 kg m 2 , and is rotating at ω<br />
= 4 rev/min. A child whose mass is m = <strong>30</strong> kg jumps onto the edge of the merry-go-round, heading<br />
directly toward the center at 6 m/s. What is the new angular speed of the merry-go-round<br />
immediately after the child has boarded it?<br />
A) 1.76 rev/min B) 3.64 rev/min C) 2.50 rev/min<br />
D) 6.40 rev/min E) 4.00 rev/min<br />
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