When light goes into a denser medium (and any medium is denser than vacuum) it slows down. For instance the speed in air is: 11.000293=99.97% of this speed, which seems like almost the same ...Answer:
Explanation:When light goes into a denser medium (and any medium is denser than vacuum) it slows down. For instance the speed in air is: 11.000293=99.97% of this speed, which seems like almost the same ...
It's the Doppler Effect that "up and down sound."
I was on Yahoo--- Brainly doesn't have an option for Credientials or Site credit, so I'll just put this in the quotes:
<span>The formula for doppler effect is always (s is speed and f is frequency): </span>
<span>f_perceived.by.observer = f_of.emitted.wave * (s_wave + s_observer) / (s_wave + s_source.of.wave) </span>
<span>And you should pay attention to the signs: </span>
<span>s_observer is positive if the receiver is moving towards the source, negative otherwise </span>
<span>s_source.of.wave is positive if the source is moving away from the observer, negative otherwise </span>
<span>Applying it to this case: </span>
<span>s_source.of.wave = ? (positive), speed of ambulance </span>
<span>s_observer = + 2.44 m/s speed cyclist </span>
<span>f_of.emitted.wave =1800 Hz frequency of whine </span>
<span>f_perceived.by.observer = 1760 frequency heard by cyclist </span>
<span>s_wave = 343 m/s speed of sound in air </span>
<span>Now you know every value in the equation for doppler effect except by s_source.of.wave, so you can solve for s_source.of.wave.</span>
1. lifts it chest high
The force opposing to this action is the force due to
gravity. Therefore the work done is:
W1 = m g d
where m is mass of the barbell, g is gravity and d is displacement
2. holds it for 30 seconds
Work is a product of force and displacement, since there
is no displacement, therefore work done is zero.
W2 = 0
3. puts it down slowly
If the barbell was dropped, then it would simply be a free
fall. But since it was not, so the work done here is also equal to the weight
of the barbell times displacement:
W3 = m g d
We can see that W1 = W3, and since W2 = 0, therefore the answer
is:
<span>w3 = w1 > w2</span>
<h2><em><u>B</u></em></h2><h2><em><u>THE EYE OF THE STORM IS CALM</u></em></h2>
Answer:
Nuclear fusion
Explanation:
In fusion, many nuclei (the centers of atoms) combine together to make a larger one (which is a different element). ... A star's mass determines what other type of nucleosynthesis occurs in its core (or during explosive changes in its life cycle).
