Question

A person whose eyes are 1.70 m above the floor stands in front of a plane mirror. The top of her head is 0.140 m above her eyes. (a) What is the height of the shortest mirror in which she can see her entire image? (b) How far above the floor should the bottom edge of the mirror be placed?

Answer 1

a) The menimum height is the half of the toatl length:

$h = \frac{L}{2} +\frac{d}{2}$

$h = \frac{1.70}{2} +\frac{0.140}{2} = 0.92 m$

b) it should be placed at:

$H = \frac{L}{2} = 0.85 m$