A lead pencil consists of a cylinder of wood with a solid cylinder of graphite filled in the interior.The diameter of the pencil is 7 mm and the diameter of the graphite is 1 mm.If the length of the pencil is 14 cm, find the volume of the wood and that of the graphite.[Assume π = 22 7 ]

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A lead pencil consists of a cylinder of wood with a solid cylinder of graphite filled in the interior.The diameter of the pencil is 7 mm and the diameter of the graphite is 1 mm.If the length of the pencil is 14 cm, find the volume of the wood and that of the graphite.[Assume   π  =      22    7  ]

nelagodafsed · Accepted Answer

Radius (      r    1  ) of the pencil   =  (      7    2    )  m  m  =  (      0.7    2    c  m  =  0.35  c  m  )  (  10  m  m  =  1  c  m  ) Radius (      r    2  ) of the graphite   =  (      1    2    )  m  m  =  (      0.1    2    )  c  m  =  0.05  c  m Height (h) of the pencil = 14 cm Volume of wood in the pencil  =  π  (      r    1    2    −      r    2    2    )  h    =  [      22    7        (    (    0.35          )      2        −    (    0.05    )          )      2        ×    14    ]  c      m    3      =  [      22    7    (  0.1225  −  0.0025  )  ×  14  ]  c      m    3      =  (  44  ×  0.12  )  c      m    3      =  5.28  c      m    3  Volume of the graphite   =  π      r    2    2    h  =  [      22    7    ×  (  0.05      )    2    ×  14  ]  c      m    3      =  (  44  ×  0.0025  )  c      m    3      =  0.11  c      m    3

A lead pencil consists of a cylinder of wood with a solid cylinder of graphite filled in the interior.The diameter of the pencil is 7 mm and the diameter of the graphite is 1 mm.If the length of the pencil is 14 cm, find the volume of the wood and that of the graphite. [Assume pi=(22)/(7)]

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