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Homework Help: Focal length of glasses

  1. Apr 23, 2009 #1
    1. The problem statement, all variables and given/known data
    Veronique is nearsighted; she cannot see clearly anything more than 6.50 m away without her contacts. One day she doesn't wear her contacts; rather, she wears an old pair of glasses prescribed when she could see clearly up to 8.00 m away. Assume the glasses are 2.0 cm from her eyes.

    a. What is the focal length of Veronique's glasses?
    b. What is the greatest distance an object can be placed so that she can see it clearly with these glasses?

    2. Relevant equations


    3. The attempt at a solution

    I literally have no idea where to start. any hints appreciated
  2. jcsd
  3. Apr 23, 2009 #2
    so i got -7.98 for the focal length. but i dont know how to do b
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