In a church choir loft, two parallel walls are 3.43m apart. The singers stand against the north wall. The organist faces the south wall, sitting 0.687m away from it. So that she can see the choir, a flat mirror 0.518m wide is mounted in the south wall, straight in front of the organist. What width of the north wall can she see? Answer in units of m.
2006-12-10 09:57:12 · 2 answers · asked by glorydefined 1 in Science & Mathematics ➔ Physics
I will assume that the distance between her eyes is negligible.
The angle of reflection of light equals the angle of incidence. Any light coming from wider than her field of vision into the mirror will not be visible to her. This sets the maximum angle of incidence as
a
where tan(a)=(w/2)/3.43
where w is the visible width of the North wall
since this angle is equal to the angle of reflection:
tan(a)=(.518/2)/.687
so
w/3.43=.518/.687
w=3.43*.518/.687
=2.586 m
j
2006-12-10 10:14:00 · answer #1 · answered by odu83 7 · 1⤊ 2⤋
It depends where she is. Make a scale drawing, put the organist wherever you like 0.687m from the south wall. measure the distance on your drawing and scale-it.
2006-12-10 10:04:36 · answer #2 · answered by Anonymous · 0⤊ 0⤋