1)
a being from a distant galaxy is 2m tall & has one eye situated exactly at the top of his head.What is the least lenght of mirror that it needs in order to see itself fully in the mirror?
need help urgently,thx
2006-09-06 13:14:10 · 9 answers · asked by boh990 2 in Education & Reference ➔ Homework Help
. . . so presumably the mirror didn't say you were the fairest of them all? . . .
2006-09-06 13:29:22 · answer #1 · answered by Astra 6 · 0⤊ 0⤋
1m, laura valsa was correct.
The question can be solved using a triangle. Light always travels in straight lines and you know that the mirror will reflect evenly. The line of sight must travel from the exact top of the being's head to the bottom of the its body.
Draw a line 2m high, and then draw a parallel line (representing the mirror) and distance away from it. You will find that when the you draw the line from the head to the mirror, when it is reflected so that it meets the feet, it will be at exactly half way down the mirror. You can also experiment by having the mirror in different places, but it makes no difference.
However, this is the length of the mirror starting from the top of the being, exactly level with the eye and ending a metre below this. Obviously if the mirror were any lower, the being would not be able to see its eye, and any higher would be of no use.
You should draw two ray lines, both starting from the eye, one going to the lowest point and the other to the highest point (the eye) and where these two rays hit the mirror is the least length necessary, 1m, or exactly half of the height. I believe that it does not matter where the eye is situated on the being also.
I hope that this is clear for you to understand.
2006-09-08 07:34:07 · answer #2 · answered by Chris 3 · 0⤊ 0⤋
Hmmm, well I believe the answer is one molecule of glass assuming the being has super sight and can see the mirror from an infinite distance. Since the object in the mirror is a height that is proportional to the distance from where it is being viewed the being can back up as far as it can still see the mirror and is as small as a mirror can be.
2006-09-06 13:21:41 · answer #3 · answered by odu83 7 · 0⤊ 0⤋
1m
Size of the mirror has to be atleast 1/2 of the object.
2006-09-06 13:18:03 · answer #4 · answered by laura_valsa 2 · 0⤊ 0⤋
depends on how close you are to the mirror a 2inch mirror at a suitable distance would show the whole body you would just need very good eyesight to see yourself !!
2006-09-06 13:22:29 · answer #5 · answered by jules 2 · 0⤊ 0⤋
Any length mirror will suffice if the being's eyesight is good enough.
2006-09-06 13:19:09 · answer #6 · answered by Jay 6 · 0⤊ 0⤋
you didnt mention how far the being is from the mirror
2006-09-06 13:20:43 · answer #7 · answered by me 5 · 0⤊ 0⤋
it depends how far from the mirror the being is, it's a trick question.
2006-09-06 13:16:47 · answer #8 · answered by JenJen 2 · 2⤊ 0⤋
Urgently? Tell him not to worry, I'm sure he looks fine.
2006-09-06 13:16:51 · answer #9 · answered by Belinda B 3 · 1⤊ 0⤋