Question

A sub-marine is 300 m horizontally out from the shore and 90 m beneath the surface of the water. A laser beam is sent from the sub so that it strikes the surface of the water at a point 210 m from the shore. If the beam just strikes the top of a building standing directly at the water's edge, find the height of the building.

Answer 1

the height of the building h= 133.37 m

Step-by-step explanation:

from the figure,

The angle of incidence of water surface is

`\theta_1= tan^(-1)((90)/(90) )`

=45°

angle of reflection is

`\theta_2= sin^(-1)((sin\theta_1n_(water))/(n_(air)) )`

`\theta_2= sin^(-1)((sin45°(1.33))/(1) )`

=70.12°

The height of the building h

`h= (210)/(tan70.12\degree)`

h= 133.37 m