# mirror height

• Mar 1st 2008, 06:55 PM
rcmango
mirror height
A person whose eyes are 1.70 m above the floor stands in front of a plane mirror. The top of her head is 0.15 m above her eyes.

(a) What is the height of the shortest mirror in which she can see her entire image?
m

(b) How far above the floor should the bottom edge of the mirror be placed?
m

• Mar 2nd 2008, 12:12 AM
earboth
Quote:

Originally Posted by rcmango
A person whose eyes are 1.70 m above the floor stands in front of a plane mirror. The top of her head is 0.15 m above her eyes.

(a) What is the height of the shortest mirror in which she can see her entire image?
m

(b) How far above the floor should the bottom edge of the mirror be placed?
m

I've attached a sketch.

You will easily see that the minimum length of the mirror must be 0.925 m and
that the bottom edge of the mirror must be placed 0.85 m above the floor.

You also will see that the distance from the mirror doesn't matter.
• Mar 2nd 2008, 12:01 PM
rcmango
Thanks for the diagram, it makes it so much easier to see when its looked at that way.