If you hold a 35.27 cm square plane mirror 60.02 cm from your eyes and can just see the full length of a 4.93 m flag pole behind you, how far are you from the pole?

Respuesta :

We are given the following situation:

Where:

[tex]\begin{gathered} h_0=height\text{ of the object} \\ h_i=\text{ height of the image} \\ d_i=\text{ distance to the image} \\ d_0=\text{ distance of the object} \end{gathered}[/tex]

We will determine the height of the image by determining the height of the mirror. To do we use the area of the mirror. If the mirror is a square then its area is given by:

[tex]A=h^2[/tex]

Substituting the value of the area:

[tex]35.27cm^2=h^2[/tex]

Now, we take the square root to both sides:

[tex]\sqrt{35.27cm^2}=h[/tex]

Solving the operations:

[tex]5.9cm=h[/tex]

Therefore, the height of the image is 5.9cm.

Now, we determine the magnification using the following formula:

[tex]M=\frac{h_i}{h_0}[/tex]

Substituting the values in the formula we get:

[tex]M=\frac{0.059m}{4.93m}=0.012[/tex]

The magnification is also equal to:

[tex]M=-\frac{d_i}{d_o}[/tex]

Now, we solve for the distance of the object. First, we multiply both sides by the distance of the object:

[tex]Md_o=-d_i[/tex]

Now, we divide both sides by the magnification:

[tex]d_o=-\frac{d_i}{M}[/tex]

Now, we plug in the values:

[tex]d_o=\frac{-60.02cm}{0.012}[/tex]

Solving the operations:

[tex]d_o=-5015.23cm[/tex]

Now, the distance from the observer to the pole is the difference between the distance of the object and the distance of the image:

[tex]d=d_0-d_i[/tex]

Substituting we get:

[tex]d=5015.23cm-60.02cm=4955.2cm[/tex]

Therefore, the pole is at 4955.2 cm.

Ver imagen ZailyT145130