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A uniform rod AB of mass 2 kg and length 30 cm is at rest on a smooth horizontal surface. An impulse of force 0.2 Ns is applied to end B. The time taken by the rod to turn through at right angles will be x s, where x= .
4
[figure]
Angular impulse about C = Icm J L2= ML212
0.2 0.15= 2 (0.3)212
0.03=0.015 =2 rad/s
smooth surface, no torque afterwards: constant
t= = /22= 4 s x=4
Answer: 4
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