An echo
Refraction
Diffraction
Transmission
reflection
Answer:

Explanation:
Since,
<h3><u>1 kWh = 1 unit</u></h3>
So,
1.6 kWh = 1.6 units
If,
<h3>1 unit = 9p</h3>
1.6 units = 9p × 1.6
1.6 units = 14.4p
![\rule[225]{225}{2}](https://tex.z-dn.net/?f=%5Crule%5B225%5D%7B225%7D%7B2%7D)
Answer:

Explanation:
Assuming no energy lost, according to the law of conservation of energy, the kinetic energy of the automobile becomes potential energy after the crash:

Here m is the automobile's mass, v is the speed of the car before impact, k is the "bumper" constant and x is the compression of the bumper due to the collision. Solving for v:

We will hear the sound of siren of frequency 1553.4606 Hz.
<h3>What is Doppler Effect?</h3>
The apparent change in wave frequency brought on by the movement of a wave source is known as the Doppler effect. When the wave source is coming closer and when it is moving away, the perceived frequency changes. The Doppler effect explains why we hear a passing siren's sound changing in pitch.
according to Dopplers Effect,
![f'=[\frac{v + v_{0} }{v - v_{s} } ]f](https://tex.z-dn.net/?f=f%27%3D%5B%5Cfrac%7Bv%20%2B%20v_%7B0%7D%20%7D%7Bv%20-%20v_%7Bs%7D%20%7D%20%5Df)
![f'= [\frac{700+68.1}{700-94.8} ]* 1224](https://tex.z-dn.net/?f=f%27%3D%20%5B%5Cfrac%7B700%2B68.1%7D%7B700-94.8%7D%20%5D%2A%201224)

the frequency would be 1553.4606 Hz.
to learn more about Doppler Effect go to - brainly.com/question/9165991
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The mass of an object always stays the same since it is really just the amount of matter in an object so no matter the force applied, as long as the object does not lose or gain matter, the object stays the same