Answer:
The arrow is at a height of 500 feet at time t = 2.35 seconds.
Explanation:
It is given that,
An arrow is shot vertically upward at a rate of 250 ft/s, v₀ = 250 ft/s
The projectile formula is given by :

We need to find the time(s), in seconds, the arrow is at a height of 500 ft. So,

On solving the above quadratic equation, we get the value of t as, t = 2.35 seconds
So, the arrow is at a height of 500 feet at time t = 2.35 seconds. Hence, this is the required solution.
From the definition of apparent magnitude, we know that:

where:
m = apparent magnitude
F = corresponding flux
We also know that the flux is given by the formula:

where:
L = luminosity
d = distance
Therefore:

Now, let's apply these formulae to the same star (therefore, same luminosity), using apparent magnitude and absolute magnitude (which is defined as the apparent magnitude the star would have if it were at a distance of 10pc):

Now, let's solve for m:

= <span>

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= 13
Hence,
the apparent magnitude of the star would be m = +13
Answer:
Resonance depends on objects, this may happen for example when you play guitar in a given room, you may find that for some notes the walls or some object vibrate more than for others. This is because those notes are near the frequency of resonance of the walls.
So waves involved are waves that can move or affect objects (in this case the pressure waves of the sound, and the waves that are moving the wall).
this means that the waves are mechanic waves.
Now, in electromagnetics, you also can find resonance frequencies for electromagnetic waves trapped in things called cavities, but this is a different topic.
Explanation:
A wave is a disturbance in a medium. For example, when some pebbles are thrown in water, the water particles gets disturbed. A wave is characterized by the following parameters i.e.
Frequency
Wavelength etc
The number of oscillations or vibrations in a medium is called the frequency of a wave.
Also, the distance between two consecutive crests and troughs is called the wavelength of a wave. The relationship between the wavelength and the frequency of a wave is given by :
Speed of wave = frequency × wavelength