When a sound wave moves past a point inair, what happens to the density of air at thispoint? 1.there is no change in the density of air.2.the density of air increases and thendecreases as the sound wave passes. correct3.there is no air after the sound wavepasses

2.The density of air increases and thendecreases as the sound wave passes.

Explanation:

Sound waves are mechanical waves, which consist of oscillation of the particles in the medium where the wave is transmitted through.

Sound waves are also longitudinal waves, which means that the direction of oscillations of the particles of the medium occurs in a direction parallel to the direction of motion of the wave (so, essentially back and forth).

Due to the nature of longitudinal waves, they create alternating regions of the medium where the density of particles are higher and lower. The former are called compressions, while the latter are called rarefactions.

Therefore, when a sound wave travels through the air, the density of one region of air continuously changes: compression first (high density), rarefaction then (lower density), then compression again, etc..

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.