Answer:
air does not have a modulus of rigidity.
Explanation:
Since air is completely elastic medium, that is, it does not have a modulus of rigidity, therefore sound waves in air are longitudinal.
Answer:
At higher elevations, there are fewer air molecules above a given surface than a similar surface at lower levels. ... Since most of the atmosphere's molecules are held close to the earth's surface by the force of gravity, air pressure decreases rapidly at first, then more slowly at higher levels.
Explanation:
Velocity, unlike speed, includes a direction.
Velocity is a vector quantity which is defined by magnitude and direction.
Speed is a scalar quantity. It is the rate at which an object moves regardless of which direction.
Radars are frequently used to identify distance and speed, such as how far away an object is or how fast it is moving. <span>The </span>radar<span> device can then use the change in frequency to </span>determine the speed<span> at which the </span>car<span> is moving. In laser-</span>speed<span> guns, waves of light are </span>used<span> in place of radio waves.</span>