The human lungs have a volume of only about 4 L, yet an internal surface area of nearly 100 m2. Why is this important, and how is this possible?

Janice is grilling a steak for her July 4th barbecue dinner. The steak initially weighs 300 grams and is 25 mm thick. After grilling it for a while, she considers the steak done, and measures it again: it now weighs 215 grams, and is 15 mm thick. For both the cooked and uncooked steak, she uses the thumb-test to determine the done-ness, i.e. she uses her thumb (area ~5cm2) to push down with a force of 5 N. The uncooked steak compresses by 7 mm, and the cooked steak by 2 mm. The change in elasticity of the steak on cooking is due partly to the loss of water volume (so that existing bonds get closer together) and partly to the creation of new bonds. Assume all of the difference in raw vs. cooked steak thickness is due to water loss that makes it thinner (25 mm thick in the uncooked steak, versus 15 mm thick in the cooked steak), and that the other dimensions of the steak (length and width) have not changed. By what percentage has the steak's volume decreased from the original value?…

Although human lung capacity is about 3 liters per lung, the tidal volume, representing the amount of air that is breathed in and out with each breath is much -3 less, typically about 250 cm7 per lung. The cycle of inhalation and exhalation during normal activity can be represented as a sine curve, as shown in the figure below, where the amount of air in each lung before inhalation begins is about 1.09 liters (the functional residual capacity of the lung) and the time on the horizontal axis has been calculated with the average adult breathing rate of 16 breaths per minute. Volume of air in lungs (L) 1.34 1.09 mm minimum height maximum height 15 We can model each lung as a cylinder of radius 5.95 cm in which one end cap is free to move up and down, increasing and decreasing the volume of the model lung during the breathing process. (a) Using the data above, calculate the minimum and maximum heights (in cm) of the model lung during the breathing process. (Round your answers to at least…

The population of India can be modeled by the function P(t) = 1462(1 +0.0177) where P(t) measures the population in millions andt represents the number of years since 2000. 1. Using this model, what was the population of India in 2009? 2. Predict the population of India in 2019. 3. If this growth rate continues, in what year will the population of India reach 2 billion people? Hint: