The writing on the passenger-side mirror of your car says "warning! objects 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 1.5 m -tall cyclist on a bicycle is 30 m from the mirror. you are 1.4 m from the mirror, and suppose, for simplicity, that the mirror, you, and the cyclist all lie along a line.
- you are 2.2 m from the image of the cyclist
a) what is the image height?
b) what would the image height have been if the mirror were flat?
c) what is the angular size of the image of the cyclist?
d) what would the angular size of the cyclist's image have been if the mirror were flat?
e) explain why is there a warning label on the passenger-side mirror?

image height = 0.1  m

image height if flat mirror 1.5 m

θ =  2.86 degree

θ  if flat mirror  =  41.10 degree

warning label  because image is small than object

Explanation:

given data

focal length = -80 cm = 0.80 m

tall = 1.5 m

cycle distance  d1 = 30 m

we from mirror distance = 1.4 m

image of cyclist d2 = 2.2 m

to find out

image height ,  image height if mirror flat , angular size , angular size if mirror flat and why is there a warning label

solution

we apply here formula

image height / tall =  d2 / d1

image height / 1.5 =  2 / 30

image height = 0.1  m

and

image height if mirror flat

so height will be same as object height 1.5 m

and

angular size image formula is

θ =  2tan^-1 ( image height /2d2)

θ =  2tan^-1 ( 0.1 /2(2) )

θ =  2.86 degree

and if mirror is flat

angular size

θ =  2tan^-1 ( image height /2d2)

θ =  2tan^-1 ( 1.5 /2(2) )

θ =  41.10 degree

and

we know image is small than object so we can think object is large distance than in real so if we stop instantly so other person will be surprised he have time to stop vehicle

most voltage drop calculators want the distance between the source and destination. then internally, they double it so both the source and return wires are calculated. but you need to know which distance the calculator uses so you're not half of what you should be or double what you should be.

most circuit breakers will not take a #6 directly, so the electrician will have to splice on a smaller pigtail. you also have to upsize the grounding wire when you upsized the ungrounded (hot) wire (see note in 250.122). this will preclude using most cable assemblies, as a cable with #6 copper will most likely only have a #10 grounding conductor. you need a #6 grounding conductor if the circuit is 20a. a #8 cable is no better, as it will have a #10 grounding conductor too. but most 20a breakers will take a #8 directly.

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d₁ = displacement of tern from arctic to antarctic = 11000 miles

d₂ = displacement of tern from antarctic to arctic =   - 11000 miles

d = total displacement for the journey

total displacement for the journey is given as

d = d₁ + d₂

d = 11000 + (-11000)

d = 0 miles

t₁ = time of travel from arctic to antarctic = 3 months = 3 x 30 days = 90 days

t₂ = time of travel from antarctic to arctic = 3 months = 3 x 30 days = 90 days

t = total time of travel

total time of travel is given as

t = t₁ + t₂

t = 90 + 90

t = 180 days

average velocity is given as

average velocity = total displacement/ total time

v = d/t

v = 0/180

v = 0 miles/day