They should look for <span>a report from an independent scientific research firm,
even if they have to pay for it.
In preparing its report, the firm would have already surveyed many of the </span>
<span>citizens from several other towns that currently add fluoride to their water,
plus a lot of other relevant medical research on the subject.</span>
A. The amount of work increases.
Imagine you are pushing a box on a flat surface. Now imagine pushing it up a steep hill. It gets harder and that's how I remember this.
Hope this helps.
Answer:
4
Explanation:
Refraction is the bending of light when it moves from one medium to another.
In the situation described:
- The average speed of light changes when it goes to another medium. The speed of light in water is less than in air.
- When velocity/speed changes, the index of refraction changes as well. Water's index is greater than in air.
- Since, speed changes, wavelength changes too.
- Only the frequency remains the same. The rates of vibration stays the same.
Correct choice is #4.
Answer:
The angle between two just-resolvable stars for the Arecibo telescope is
.
Explanation:
The resulting image in a telescope obtained from an object is a diffraction pattern.
That diffraction pattern is obtained because the light encounters different obstacles on its path inside the telescope (interact with the walls and edges of the instrument).
The diffraction pattern is composed by a central disk, called Airy disk, and diffraction rings.
The angular resolution is defined as the minimal separation at which two sources can be resolved one for another, or in other words, when the distance between the two diffraction patterns maxima is greater than the radius of the Airy disk.
The angular resolution can be determined in an analytical way by means of the Rayleigh criterion.
(1)
Where
is the wavelength and D is the diameter of the telescope.
Notice that it is necessary to express the wavelength in the same units than the diameter.
⇒
Finally, equation 1 can be used.
Hence, the angle between two just-resolvable stars for the Arecibo telescope is
Acceleration due to gravity