F4 Phsyic Past Paper !(2)

solve question 69 please!

圖片參考:http://imgcld.yimg.com/8/n/HA05329604/o/7012082200...

2 個解答

評分
  • 天同
    Lv 7
    8 年前
    最愛解答

    First draw the image of the pole P'Q' , which is at a distance of (4 + 1) m = 5 m behind the mirror.

    Now join P'and E, which should passes through M in order for the eye at E to see the top of the pole.

    Similarly, join Q' to E, which should passes through N in order for the eye at E to see the bottom of the pole.

    Hence, triangle EMN and triangle EP'Q' are similar triangles. Since the eye E is 1 m from the mirror MN and (5+1) m = 6 m from the image of the pole P'Q'

    MN/1 = P'Q'/6

    h/1 = 3/6

    i.e. h = 0.5 m

  • 8 年前

    圖: http://s16.postimage.org/4nsnway9f/physics.png

    AF = image of the wall

    DG = the mirror

    Consider Triangle EDG and EAF (which are similar triangle),

    DG:AF = CB:CA

    >> h:3 = 1:6

    Therefore, h = 0.5m

    資料來源: Myself
還有問題嗎?立即提問即可得到解答。