Acounterflow double-pipe heat exchanger is used to heat water from 20 to 40◦c by cooling an oil from 90 to 55◦c. the exchanger is designed for a total heat transfer of 59 kw with an overall heat-transfer coefficient of 340 w/m2 · ◦c. calculate the surface area of the exchanger.

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.

The respiratory system removes oxygen and water from the body. select the best answer from the choices provided t f

The free body diagram shows a box being pulled to the left up a 25-degree incline. the magnitude of the normal force is