Answer:
<u>because of the doppler effect</u>
Explanation:
<em>Remember</em>, the doppler effect refers to the changes in sound (frequency of sound) observed by a person who is in a position relative to the wave source.
In this example, we notice as the train comes closer to the boy, the sound becomes louder also increasing the pitch slightly, the doppler effect sets in when the train passes the boy because the boy notices a decrease in the pitch of the moving train.
We learn from the change in the observed sound of the train that the frequency of the sound is determined by the distance of the observer from the wave source.
In other words, the closer the source of the sound to the observer; the faster it travels to the observer, however, the farther it is; the lesser it is; the greater the sound heard.
<h3><u>Answer;</u></h3>
Frequency
<h3><u>Explanation;</u></h3>
- <em><u>Waves are disturbances that travel through a material medium. There are several characteristics of waves, which includes; wavelength, frequency, period and amplitude. </u></em>
- Amplitude is the maximum displacement of wave particles, or simply the height of the wave, measured in meters.
- Wavelength is the distance between adjacent crests or troughs in a transverse wave or between two successive rarefaction or compressions in a longitudinal wave, measured in meters.
- Period is the time it takes for one complete wave to pass a given point, measured in seconds.
- <em><u>Frequency is the number of complete waves or cycles that pass a point in one second, measured is inverse seconds, or Hertz (Hz).</u></em>
The situation (heat going through the ceiling) describes
conduction ... heat going from one place to another by
soaking through some material.
A). This is the one. Heat goes from from the marshmallow
to your hand by soaking through the wire. This is conduction too.
B). No. The heat in the room goes from the floor to the ceiling
because the warm air rises and carries it there. This is convection.
C). No. There's nothing for the heat to soak through between
the sun and the roof, and nothing that can move from the sun
to the roof and bring the heat with it. This is radiation.
D). No. Cold water sinks from the surface to the bottom because
warm water rose from the bottom to the surface, taking heat with it.
This is convection.
