Problem 1.

A person stands

**40 m**from a flag pole. With a protractor at eye level, he finds the angle at the top of the flag pole with the horizontal is**25.0 degrees**. How high is the flag pole? The distance from his feet to his eyes is**1.8 m.**
Solution:

We draw the picture of the problem, where we show the angle 25 degree, the person's height, and the distance between the person and the pole.

From the right triangle

**ABC**we can find the distance**BC**(we know the angle and we know the distance**AB = 40 m**):
The distance

**OB**is equal to the height of the person (which is**1.8 m**). Then we can find the whole height of the pole:
Problem 2.

Solution:

In this problem we need to use the relation between the frequency , wavelength , and the speed of the light (wave):

Then