Sound waves are introduced to a medium by a vibration. For example, a vibrating guitar string forces surrounding air molecules to be compressed and expanded. This creates a pressure disturbance consisting of an alternating bands of compressions and rarefactions. The vibration travels from particle to particle through the medium, transporting energy as it moves.
The amount of energy which is transported past a given area of the medium per unit of time is known as the of the sound wave and is reported as
power
area
.

A) frequency
B) intensity
C) pitch
D) wavelength

You carry a 7.0-kg bag of groceries 1.2 m above the ground at constant speed across a 2.7m room. how much work do you do on the bag in the process? (a) 157j (b) 0.00j (c) 185j (d) 82j

Glass is transparent to visibile light under normal conditions; however, at extremely high intensities, glass will absorb most of the light incident upon it. this works through a process known as multiphoton absorption. in this process, several photons are absorbed at the same time. if very intense light whose photons carry 2ev of energy is shined onto a material with a band gap of 4ev, that light can be absorbed through two-photon absorption, because two photons have the right amount of energy to bridge the band gap. what is the minimum number of photons of 800-nm light that are needed to equal or exceed the band gap of fused silica glass

Acrow drops a 0.11kg clam onto a rocky beach from a height of 9.8m. what is the kinetic energy of the clam when it is 5.0m above the ground? what is its speed at that point?