The typical diameter of an alveolus is 0.3 mm. The surface tension of water is about 70 dyne cm-1. The dyne is the unit of force in the cgs system: 1 g cm s-2. It is converted to N by multiplying by 10-3kg g-1x 10-2m cm-1 = 10-5 kg g-1 m cm -1. What is the pressure within this alveolus assuming no surfactant at mechanical equilibrium? Give the answer in Pascals (N m-2) and in mm Hg.

Astudent is performing an experiment comparing sound and light waves. the student gathers the following data. what conclusion does the student most likely make based on this data? light waves always travel the same speed; however, the speed of sound is determined by the medium that it travels through. all sound waves always have the same energy, so the temperature of the medium does not affect wave speed. light needs to vibrate particles, so it travels fastest in tightly packed solids, while sound does not need a medium, so it travels fastest in a gas. tightly packed particles in solids slow down the light waves; however, sound waves make particles bounce into each other, so they travel faster in solids.

An equinox occurs when a. neither end of earth's axis is tilted toward or away from the sun. b. the north end of earth's axis is tilted away from the sun. c. the north end of earth's axis is tilted toward the sun. d. earth's axis is parallel to the sun's rays. select the best answer from the choices provided a b c d

What are similarities and differences of reflection, refraction, diffraction and absorption?