Physics-
General
Easy

Question

Two solid uniform disks of equal mass each are mounted to rotate about an axis fixed through the center of the disk. Each disk is initially at rest. The radii of the disks are r subscript 1 end subscript less than r subscript 2 end subscript A force F is applied to each disk at its edge for the same amount of time. Assume that friction at pulley axis is negligible. What statement is true about the kinetic energy (K) and magnitude of angular momentum (L) of the disks?

  1. L subscript 1 end subscript equals L subscript 2 end subscript text  and  end text K subscript 1 end subscript less than K subscript 2 end subscript    
  2. L subscript 1 end subscript less than L subscript 2 end subscript text  and  end text K subscript 1 end subscript equals K subscript 2 end subscript    
  3. L subscript 1 end subscript less than L subscript 2 end subscript text  and  end text K subscript 1 end subscript greater than K subscript 2 end subscript    
  4. L subscript 1 end subscript less than L subscript 2 end subscript text  and  end text K subscript 1 end subscript less than K subscript 2 end subscript    

The correct answer is: L subscript 1 end subscript equals L subscript 2 end subscript text  and  end text K subscript 1 end subscript less than K subscript 2 end subscript

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