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The writing on the passenger-side mirror of your car says \"Warning! Objects in

ID: 1507257 • Letter: T

Question

The writing on the passenger-side mirror of your car says "Warning! Objects in mirror are closer than they appear" . There is no such warning on the driver's mirror. Consider a typical convex passenger-side mirror with a focal length of -80 cm. A 1.6-m-tall cyclist on a bicycle is 28 m from the mirror. You are 1.0 m from the mirror, and suppose, for simplicity, that the mirror, you, and the cyclist all lie along a line.

How far are you from the image of the cyclist?

How far would you have been from the image if the mirror were flat?

What is the image height?

Explanation / Answer

  a
1/f = 1/di + 1/do
1/-0.80 = 1/di + 1/28
di = -0.777 m behind the mirror
so you are 1.0 + 0.777 = 1.777 m from the image

b
if flat mirror
the image would have been 28 m behind so 1.0 + 28 = 29 m

c
hi/ho = di/do
hi/1.6 = 0.777 / 28
hi = 0.0444 m