Stoke's Law problem (3 parts)

Stokes' Law describing partial sedimentation is given by: Rate = [(gd^2)(Δρ)]/18η where g = 9.81 m s^-2 is gravitational acceleration. Δρ is the density difference between particles and the air, air viscosity of η = 1.67E-4 g cm^-1 s^-1 and d is the particle diameter in centimeters. a. Calculate the weight(g) of one cubic centimeter of air at 1.0 atm and 15 degrees celsius. b. Assume particles have a density of 2.45 g cm^-3 and are being released by a 100 m smokestack. How long does it take (s) a 25μm particle to settle to the ground? c. It rains exactly once a week. What is the smallest particle size (μm) that can settle to the grounds b... click for more

How Much Energy is Needed to Heat [Amount] of Water by [Amount] of Degrees (and what is the cost)?

The average home has a 200 liter (50-60 gallon) hot-water tank, which is effectively drained and replenished three times per day. Assume that the entering tap water is 10 degrees C and is heated to 57 degrees C. Given an average energy from sunlight of 1.53 kJ/cm2 per day, how large would the collection area (in m2) of a solar water heater need to be if its efficiency is 28%? Assume that the price of a solar collector is $375/m2. How much would it cost to install this hot water system?

Ratio / Proportion Problem

Petroleum consumption in the US in 1990 supplied about 35.6E15 kJ of energy. Of this quantity, about 14.4E15 kJ was supplied by foreign sources. The transportation sector is the major user of petroleum, accounting for 23.2E15 kJ of consumption. Overall automobile fuel economy in the US was about 21 miles per gallon in 1990. Automobile efficiencies in Europe and Japan were about 27 mpg. If the US had averaged 27 mpg in 1990, how much less petroleum (expressed as kJ) would have been imported?

Petroleum consumption in kJ

Petroleum consumption in the US in 1990 supplied about 35.6E15 kJ of energy. Of this quantity, about 14.4E15 kJ was supplied by foreign sources. The transportation sector is the major user of petroleum, accounting for 23.2E15 kJ of consumption. Overall automobile fuel economy in the US was about 21 miles per gallon in 1990. Automobile efficiencies in Europe and Japan were about 27 mpg. If the US had averaged 27 mpg in 1990, how much less petroleum (expressed as kJ) would have been imported?

Photosynthesis problem

47. a) Photosynthesis is estimated to produce 390.0 g (dry weight) of plant matter per square meter, 50% of which is carbon. Calculate the total number of grams of carbon "fixed" each year by 1000 square meters. b) The photosynthetic reaction can be represented as: 6CO2 + 6H2O -> C6H12O6 + 6O2 Of the glucose produced, 40.0% is used by the plant to fuel respiration; the rest is converted to plant matter. Calculate the total moles of glucose produced annually in our reference 1000 square meter area. c) Each mole of glucose produced represents the absorption of 2803 kJ of solar energy. If the average energy available from the sunlight over an eight-month period is 2.0 kJ/cm2 per day, what ... click for more