A 5cm mirror is just large enough to show the whole image ...

Discussion in 'Physics' started by famous, Nov 24, 2012.

  1. famous

    Thread Starter New Member

    Nov 24, 2012
    3
    0
    A 5cm mirror is just large enough to show the whole image of a tree when held 20 cm from the eye of the observer whose distance to the tree is 100 m. What is the height of tree?
     
  2. MvGulik

    Member

    Nov 3, 2011
    40
    9
    Mmm. Lets see.

    Find total light traveling distance.
    Divide that by the eye to mirror distance.
    Multiply that by height of the mirror.
    That should return the height of the tree.
     
    Last edited: Nov 24, 2012
  3. Markd77

    Senior Member

    Sep 7, 2009
    2,803
    594
    Try drawing it, essentially I think it is the same as looking through a 5cm hole, you should be able to calculate the ratios of the triangle sides and the height of the tree. (The distance from the eye to the tree should really include the distance to the mirror, and it actually makes a difference which direction you are holding the mirror relative to the tree, but the question is probably ignoring that).
     
  4. Syn7

    New Member

    Nov 13, 2012
    11
    1
    5.1m........... :confused:
     
  5. atferrari

    AAC Fanatic!

    Jan 6, 2004
    2,644
    759
    Maybe 25 m high? Mental calculation
     
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