Answer:
After 12 seconds, the area enclosed by the ripple will be increasing rapidly at the rate of 1206.528 ft²/sec
Explanation:
Area of a circle = πr²
where;
r is the circle radius
Differentiate the area with respect to time.

dr/dt = 4 ft/sec
after 12 seconds, the radius becomes = 
To obtain how rapidly is the area enclosed by the ripple increasing after 12 seconds, we calculate dA/dt


dA/dt = 1206.528 ft²/sec
Therefore, after 12 seconds, the area enclosed by the ripple will be increasing rapidly at the rate of 1206.528 ft²/sec
Answer:
2.62seconds
Explanation:
Speed is defined as the ratio of the distance covered by a body with respect to time.
Speed v = Distance (s)/Time (t)
For a traveling sound wave, the distance between the source of a sound and the reflector is '2S'.
Speed v = 2 × distance (S)/Time (T)
V = 2S/t
2S = vt
Given speed of the wave = 342m/s
Distance covered = 450m
t = 2S/v
t = (2×450)/343
t = 900/343
t = 2.62seconds
It will take him 2.62seconds for him to hear his own voice echo off of the wall.
<h3><u>Answer and explanation;</u></h3>
- <u>Melting point</u> is defined as the temperature at which solid and liquid phases are in equilibrium. It is the temperature at which a solid changes state from solid to liquid at atmospheric pressure.
- <u>Boiling poin</u>t is the temperature at which the vapour pressure of a liquid is equal to the external pressure. It is the temperature at which a substance changes from a liquid into a gas.
- <u>The flash point </u>of a flammable liquid or volatile liquid is the lowest temperature at which it can form an ignitable mixture in air. At this temperature the vapor may cease to burn when the source of ignition is removed.
Answer: You don't do work.
Explanation: If you don't do the work you don't have to ask this question. With work comes labor. With labor comes change. With change comes resistance and people do not like change. IT causes anger, so if you stop doing work and stick to the important supply like food, water, and shelter you don't have to go through the trouble of this and we can live in a peaceful environment for this world to be better than it is. People do to much, it's a natural fact but you can change the entire picture. If you read all of this thank you for accepting the fact of life.
Answer:
Explanation:Naturally occurring radioactive materials are present in its crust, the floors and walls of our homes, schools, or offices and in the food we eat and drink. There are radioactive gases in the air we breathe. Our own bodies - muscles, bones, and tissue - contain naturally occurring radioactive elements.