Question

A bird, h = 370 cm tall. lands s = 49.8 cm away from a diverging mirror with focal length/ 28.3 cm. 4. [Ipt] Taking the mirror to be located at x = 0 cm, at what (signed) distance from the mirror is the image located? Correct, computer gets: -18.0 cr The bird mistakes its reflection for another bird and walks toward the mirror to say hello. The "bird in the mirror" also appears to walk toward the mirror s. [Ipt but seems to change in size. When the bird is 24.0 cm from the mirror, how tall is its image? Answer: Incorrect, tries 3/15. Submit All Answers Last Answer: 2.0m

I was hope if someone could help me figure it out, and explain one question for me please.   what variables is not changing while the bird is walking toward the mirror escape its height? thanks.

Answer 1

4. s = 49.8 cm

f = - 28.3 cm (f is -ve for diverging)

Applying mirror equation,

1/f = 1/s + 1/s'

1/(-28.3) = 1/49.8 + 1/s'

s' = - 18 cm

5. s = 24 cm

1/(-28.3) = 1/24 + 1/s'

s' = - 13 cm

m = - s'/s = hi / ho

13 / 24 = hi / 3.70

hi = 2 cm