Answer:
The laws of physics take the same form in all inertial frames of reference. As measured in any inertial frame of reference, light is always propagated in empty space with a definite velocity c that is independent of the state of motion of the emitting body.
<u>Answer:</u>
<em>When red light enters the lens its wavelength decreases but its frequency remains the same.
</em>
<u>Explanation:</u>
Lens is made of glass which is a <em>denser medium</em> when compared with air. Thus light will undergo refraction and bend toward the normal. On entering a denser medium from rarer medium the speed of light decreases.
<em>Speed, frequency and wavelength of an electromagnetic wave</em> are related according to the equation.
<em> v=ϑλ
</em>
Where is <em>v is the frequency, λ is the wavelength and v is the speed of the em wave.
</em>
On entering the lens the wavelength of the red light as well as speed decreases but the<em> frequency remains the same.
</em>
Answer:
58.5 m
Explanation:
First of all, we need to find the total time the ball takes to reach the water. This can be done by looking at the vertical motion only.
The initial vertical velocity of the ball is

where
u = 21.5 m/s is the initial speed
is the angle
Substituting,

The vertical position of the ball at time t is given by

where
h = 13.5 m is the initial heigth
is the acceleration of gravity (negative sign because it points downward)
The ball reaches the water when y = 0, so

Which gives two solutions: t = 3.27 s and t = -0.84 s. We discard the negative solution since it is meaningless.
The horizontal velocity of the ball is

And since the motion along the horizontal direction is a uniform motion, we can find the horizontal distance travelled by the ball as follows:

Since they are rowing against the current, their velocity realtive to the groud is 20-1.5 = 18.5km/h
So the distance travelled is 18.5km/h*0.5h = 9.25km
Going back with the current their ground realative velocity is 20+1.5 = 21.5km/h so the time it takes them to return 9.25 km is 9.25km/(21.5km/h) = 0.43h ~= 26 min
<em>Answer:</em>
<em>Melting</em>
<em>Explanation:</em>
<em>I took the quiz and got it right so I am 100 percent sure the answer is, A.melting :)</em>