Answer:
d. perfectly elastic
Explanation:
According to the kinetic theory for collisions of gas molecules:
1.The loss of energy is negligible or we can say that it is zero.
2.Molecules of the gas move in a random manner.
3.The collision between molecules and with the wall of the container is perfectly elastic.That is why loss in the energy is zero.
Therefore the correct answer will be d.
d. perfectly elastic
Answer:
The car must be moving away from the person.
Explanation:
From Doppler's Effect, we know that when a sound source moves towards a stationary observer, the apparent frequency of that sound increases. While the apparent frequency decreases if the source moves away from the stationary observer.
The audible range of frequencies for a human ear is 20 Hz to 20000 Hz. Therefore, in order for the sound of a loud speaker to be audible for the person, the frequency must decrease below 20000 Hz.
<u>Due to this reason, the car must be moving away from the person.</u>
<span>The correct answer is: Chlorofluorocarbons (CFCs)
Explanation:
In simple words, CFCs are the chemical compounds made up of the following three elements:
1. Carbon
2. Chlorine
3. Fluorine
When CFCs compounds reach the upper atmosphere, the ultraviolet rays coming from the Sun break those compounds into individual elements, which then react with one of the oxygen atom of the ozone (O3) to form new compounds like chlorine monoxides. That way the ozone molecules get destroyed, resulting into the ozone depletion. Hence, the correct answer is Chlorofluorocarbons (CFCs).</span>
The force between them <em>decreases</em><em>,</em> as the square of the distance.
For example ...
-- If you move them apart to double the original distance, the force becomes (1/2²) = 1/4 of the original force.
-- If you move them apart to 3 times the original distance, the force becomes (1/3²) = 1/9 of the original force.
-- If you move them apart to 5 times the original distance, the force becomes (1/5²) = 1/25 of the original force.
(Gravity works exactly the same way.)
