# Consider a lake of constant volume 12200 km^3, which at time t contains an amount y(t) tons of pollutant evenly distributed throughout the lake with a concentration y(t)/12200 tons/km^3. assume that fresh water enters the lake at a rate of

86,008 results

1. ### Calculus - HELP URGENT PLEASE

Consider a lake of constant volume 12200 km^3, which at time t contains an amount y(t) tons of pollutant evenly distributed throughout the lake with a concentration y(t)/12200 tons/km^3. assume that fresh water enters the lake at a rate of 67.1 km^3/yr, and that water leaves ...
2. ### environmental engineering

A lake receives 8 m3/s of inflow containing 0.3 mol/m3 of a chemical. The chemical reacts with a first order rate constant of 0.01 h-1. The outflow from the lake is also 8 m3/s. Assume there was no chemical in the lake at the beginning and volume of the lake is 106 m3. What ...
3. ### math

There is a sudden growth of algae in a lake that kills other life in the water such that y tons of algae will be present after t weeks. The rate of growth of the algae is yÃƒÂ¢Ã¢â€šÂ¬Ã‚Â²=ty+t and the initial amount of algae is 7 tons. How long will it take ...
4. ### calculus

A state charges polluters an annual fee of \$20 per ton for each ton of pollutant emitted into the atmosphere, up to a maximum of 4,000 tons. No fees are charged for emissions beyond the 4,000-ton limit. Write a piecewise de nition of the fees F(x) charged for the emission of x...
5. ### THERMOCHEMISTRY

An ice hotel that is made of 410 metric tons of ice and 12200 metric tons of snow is being melted. The company is going to siphon the melted water into nearby streams. The company is using large industrial sized acethylene to do the job. Your job is to order the rigth amount ...
6. ### Math

Ventura Coal mined 6 ⅔ tons on Monday, 7 ¾ tons on Tuesday, and 4 ½ tons on Wednesday. If the goal is to mine 25 tons this week, how many more tons must be mined?
7. ### Math

Ventura Coal mined 6 ⅔ tons on Monday, 7 ¾ tons on Tuesday, and 4 ½ tons on Wednesday. If the goal is to mine 25 tons this week, how many more tons must be mined?
8. ### math

Ventura Coal mined 6 ¨ø tons on Monday, 7 ¨ú tons on Tuesday, and 4 ¨ö tons on Wednesday. If the goal is to mine 25 tons this week, how many more tons must be mined?
9. ### science

an you please solve the questions for me 1. 3 moles of pesticide of molecular mass 200 g/mole is applied to a closed system consisting of 20 m3 of water, 10 m3 of air, 1 m3 of sediment, and 0.001 m3 of fish. Determine the concentration and amount in both grams and mole units ...
10. ### algebra

Ben Cole was hired to shovel 100 tons of coal. He has been shoveling coal at a rate of 16 tons per day. After 3 days his brother Char joins him so they can finish the job faster. Char can shovel 10 tons per day. Find the amount of the 100 tons shoveled by each brother and the ...
11. ### Chemistry

Concentration 15.8 mg/L Final Volume 100.0 mL What is the concentration of phosphate in the original lake water sample if the unknown lake water sample in the option has been diluted by taking 25.0 mL of lake water and diluting it to the indicated final volume?
12. ### Math

A steel plant has two sources of ore, source A and source B. In order to keep the plant running, at least three tons of ore must be processed each day. Ore from source A costs \$20 per ton to process, and ore from source B costs \$10 per ton to process. Costs must be kept to no ...
13. ### statistics

Weights of a certain model of fully loades gravel trucks follow a normal distrbution with mean = 6.4 tons and standard deviation = 0.3 ton. Waht is the probability that a fully loaded truck of this model is a. less than 6 tons? b. more that 7 tons? c. between 6 and 7 tons?
14. ### Social Studies

Lake Michigan and Lake Huron have the same surface elevation of ___ feet 577? The ___ Channel connects Lake Huron Lake St Clair and Lake Erie South? Niagara Falls is between Lake Erie and Lake __ Ontario? Lake Ontario is connected to the St Lawrence Seaway a series of ___ 7 ...
15. ### social studies

what are the five great lakes You can find that at the site below: http://worldatlas.com/webimage/countrys/namerica/greatlk.htm they are lake superior lake michagan lake huron lake eria lake ontario
16. ### math

what is 10,000lb=_____T 5 tons, since there are 2000 lb per ton. As a follow through to the other post I did for you (cups to pints), note tons=10,000 lbs x factor tons = 10,000 lbs x (1 ton/2,000 lb)= 5 tons. Note again, how the lbs (the unit we want to lose) is gone and the ...
17. ### math

Surfact of A lake is 31 feet above the surface of B lake. B lake is half as deep as A Lake and the bottum of the B lake is 8 feet below the bottom of A Lake. how deep is each lake?
18. ### Chemistry

320.0 gallons of 15 M nitric acid were added to a lake. The initial pH p the lake was 6.30 and the final pH was 4.60. What is the volume of the lake?
19. ### chemistry

600 gallons of 15 M nitric acid were added to a lake. The initial pH of the lake was 5.90 and the final pH was 3.70. What is the volume of the lake?
20. ### Chemistry

Concentration 15.8 mg/L Final Volume 100.0 mL What is the concentration of phosphate in the original lake water sample if the unknown lake water sample in the option has been diluted by taking 25.0 mL of lake water and diluting it to the indicated final volume? •Chemistry - ...
21. ### Physics

Lake Erie contains about 4.8 x 10^17 grams of fresh water. Assume that the lake has frozen solid and that the ice starts off at -3 C. How much energy would the lake need to absorb from the Sun to cause it to evaporate completely?
22. ### Chemstry

Mercury concentration in a polluted lake is 0.0125 micrograms/L. What is the total mass in kilograms of mercury in the lake if the lake is approximately circular witha diameter of 10 miles and an average depth of 50 ft.?
23. ### geography

Will you please check my answers? 1. The largest lake in the world is located near the border of Asia and Europe. What is its name? Caspian Sea 2. What is the name of the country that shares the Iberian Peninsula with Spain? Portugal 3. Name the Great Lakes that border Canada...
24. ### chemistry

If the amount of mercury in a polluted lake is 0.40 ug/mL, what is the total mass of mercury in the lake? (The lake has a surface area of 100 mi squared and an average depth of 25 ft).
25. ### SS/WGeogrophy

which lake does the equator pass through: Lake Victoria,Lake Malawi,or lake Chad?
26. ### ALGEBRA

The amounts of e-waste generated in a region during two years were 14,200,000 tons and 10,700,000 tons. What was the total e-waste generated over these two years in the region, expressed in scientific notation? 2.49 ⋅ 107 tons 2.49 ⋅ 1014 tons 24.9 ⋅ 107 tons...
27. ### Physics

A swimmer has 8.20 x 10^-4 m^3 of air in his lungs when he dives into a lake. Assuming the pressure of the air is 95 percent of the external pressure at all times, what is the volume of the air at a depth of 10.0 m? Assume that the atmospheric pressure at the surface is 1.013 ...
28. ### Physics

Lake Erie contains about 4.8 x 10^17 grams of fresh water. Assume that the lake has frozen solid and that the ice starts off at -3 C. How much energy would the lake need to absorb from the Sun to cause it to evaporate completely? Each gram of water will require 721.5 calories ...
29. ### Physics

Lake Erie contains about 4.8 x 10^17 grams of fresh water. Assume that the lake has frozen solid and that the ice starts off at -3 C. How much energy would the lake need to absorb from the Sun to cause it to evaporate completely? Each gram of water will require 721.5 calories ...
30. ### Physics-is this correct?

Lake Erie contains about 4.8 x 10^17 grams of fresh water. Assume that the lake has frozen solid and that the ice starts off at -3 C. How much energy would the lake need to absorb from the Sun to cause it to evaporate completely? Each gram of water will require 721.5 calories ...
31. ### Physics

Lake Erie contains about 4.8 x 10^17 grams of fresh water. Assume that the lake has frozen solid and that the ice starts off at -3 C. How much energy would the lake need to absorb from the Sun to cause it to evaporate completely? Each gram of water will require 721.5 calories ...
32. ### Chemistry

If the amount of mercury in a polluted lake is 0.4 µg Hg/mL, what is the total mass in kilograms of mercury in the lake? (The lake has a surface area of 100mi^2 and an average depth of 20 ft.) I'll probably be able to solve this once I know what it's going on about. Is this ...
33. ### physical science

Volcanoes emit much hydrogen sulfide gas, H2S, which reacts with the oxygen in the air to form water and sulfur dioxide, SO2. Every 69 tons of H2S reacts with 97 tons of oxygen and forms 37 tons of water. How many tons of SO2 are formed
34. ### science

Volcanoes emit much hydrogen sulfide gas, H2S, which reacts with the oxygen in the air to form water and sulfur dioxide, SO2. Every 61 tons of H2S reacts with 86 tons of oxygen and forms 32 tons of water. How many tons of SO2 are formed?
35. ### Chemistry

A geologist removes a sample of water from a lake in Nevada where the water level has been slowly dropping over time. The sample is found to be 0.02M in borax. The lake is circular in shape and is currently 500 meters in diameter and 50 meters deep. Using the given data ...
36. ### pre-algebra

Which is heavier, The Thrust SCC that is 54 ft long and weighs 7 tons or the Spirit of America that is 47 ft long and weighs 4 tons?? The numbers need to be put into an inequality equation! Unless you have not adequately stated your question, no equation is needed. The answer ...
37. ### Physics

Lake Erie contains about 4.8 x 10^17 grams of fresh water. Assume that the lake has frozen solid and that the ice starts off at -3 C. How much energy would the lake need to absorb from the Sun to cause it to evaporate completely? Each gram of water will require 721.5 calories ...
38. ### physics

An airplane wants to drop a load of fish inot a small lake in the mountains. The plane is flying at its min speed 40 m/s, and is 50 meters above the surface of the lake. a.) Where relative to the lake should the plane be when the fish are dropped so that they land in the ...
39. ### History8

Which of the following most affects the size of the Great Salt Lake? A.the salt in the lake B. the region’s climate C. human modifications of the lake D. the minerals in the soil under the lake
40. ### Social Studies

Lake Huron is the northernmost Great Lake False? Lake Ontario is the closest Great lake to ottawa canada True?
41. ### state

Coal is carried from a mine in West Virginia to a power plant in New York in hopper cars on a long train. The automatic hopper car loader is set to put 55 tons of coal into each car. The actual weights of coal loaded into each car are normally distributed, with mean ì = 55 ...
42. ### physics

Lake Champlain, bordered by New York, Vermont, and Quebec, has a surface area of 1,126 km^2. If the energy (173 PJ) is provided by sunlight shining on the lake at an average rate of 200 W/m^2 but with only half that amount absorbed, how long will it take the lake to absorb the...
43. ### ALGEBRA

1. The cost, in millions of dollars, to remove x % of pollution in a lake modeled by C = __6,000__ (all supposed to be underlined) 300-3x a. What is the cost to remove 75% of the pollutant? b. What is the cost to remove 90% of the pollutant? c. What is the cost to remove 99% ...
44. ### Algebra

1. The cost, in millions of dollars, to remove x % of pollution in a lake modeled by a. What is the cost to remove 75% of the pollutant? b. What is the cost to remove 90% of the pollutant? c. What is the cost to remove 99% of the pollutant? d. For what value is this equation ...
45. ### Chem

If the hydroxide ion concentration in a lake is 10‐10 M what is the lake’s pH?
46. ### Biology

If the hydroxide ion concentration in a lake is 10‐10 M what is the lake’s pH?
47. ### ALGEBRA 117

1. The cost, in millions of dollars, to remove x % of pollution in a lake modeled by C= 3,000/300-3x. Please note: x is in percent, not decimal form. a. What is the cost to remove 75% of the pollutant? b. What is the cost to remove 90% of the pollutant? c. What is the cost to ...
48. ### Physics

You like to swim at a nearby lake. On one side of the lake is a cliff, and the top of the cliff is 69 m above the surface of the lake. You dive of the cliff doing somersaults so as to have an angular speed of 5.5 rev/s. How many revolutions do you make before you hit the water...
49. ### microeconomics

Earth Movers and Shakers operates 3 iron ore mines. This table shows their daily production rates given the number of miners at each mine. All of the miners work for the same wage. mine-----------tons---- # of miners mother lode------100-------25 scraping bottom---30-------10 ...
50. ### Math

Polluted water flows into a pond. The concentration of pollutant in the pond at the t minutes is modelled by the equation c(t)= 9-90,000(1/10000+3t), where c is measured in kilograms per cubic metre. a) When will the concentration of pollutant in the pond reach 6 kg/m^3? b) ...
51. ### math-I just want this check because it will be gra

Are these the correct answers and lables? 9. A hand lens increased the thickness of a line 10 to the 3rd power times.The line was 0.5 mm thick. How thick did the line appear? my ans.- 500 mm thick 10. A truck holds 10 to the 4th power times more pounds than when it is empty. ...
52. ### Physics

An engineer decides to use a successful dam design for a new lake of the same depth. If the new lake has ten times the surface area as the lake held by the original dam, what, if any, design changes are necessary for the new dam to hold back the increased amount of water? ...
53. ### Algebra

Bear Lake is 6 miles wide. The total time it took Jane to kayak back and forth across the lake was 2 hours. Her rate kayaking back was 3 times her rate going out across the lake. What was Jane's rate kayaking out across the lake?
54. ### science.

In powder mills park there is a lake called a kettle lake. describe how this lake was formed.
55. ### math / linear programming

Two factories manufacture 3 different grades of paper. The company that owns the factories has contracts to supply at least 16 tons of low grade, 5 tons of medium grade, and at least 20 tons of high grade paper. It costs \$1000 per day to operate the first factory and \$2000 per...
56. ### math

a company want to lay cable across a lake. to find the lengh of the lake, they madethe measurements 180ft and 150ft. what is the length of the lake?
57. ### Math, Algebra

1. Cost Benefit Model Environmental scientists often use cost-benefit models to estimate the cost of removing a pollutant from the environment as a function of the percentage of pollutant removed. Suppose a cost benefit function for the cost C (in millions of dollars) of ...
58. ### physics

Assume all temperatures to be exact, and neglect significant figures for small changes in dimension. A diver releases an air bubble of volume 4.0cm3cm^3 from a depth of 16mm below the surface of a lake, where the temperature is 8.0∘C. What is the volume of the bubble ...
59. ### Calculus 1

A woman at a point A on the shore of a circular lake with radius r=4 wants to arrive at the point C diametrically opposite A on the other side of the lake in the shortest possible time. She can walk at the rate of 10mph and row a boat at 5mph. What is the shortest amount of ...
60. ### Statistics

Assume there are two lakes containing trout and the weights of the trout in each lake are normally distributed. The distribution of trout weight in Lake A has a mean of 18 ounces with a standard deviation of 2 ounces. The distribution of trout weight in Lake B has a mean of 19...
61. ### chemistry

Mercury poisoning is a debilitating disease that is often fatal. In the human body, mercury reacts with essential enzymes leading to irreversible inactivity of these enzymes. If the amount of mercury in a polluted lake is 0.4 mg Hg/mL, what is the total mass in kilograms of ...
62. ### math

How much limestone (CaCO3) in kilograms would be required to completely neutralize a lake with a volume of 5.2 x 10^7 -L lake containing 5.0 x 10-3g of H2SO4 per liter?
63. ### science help pls pls

Look at the position of Location 1, Location 2, and Location 3 in this picture. Simple diagram of a lake represented by a wavy circle. The circle is labeled 'Lake,' and there are three points outside of the lake: 'Location 1' is to the northeast of the lake, 'Location 2' is to...
64. ### Alegabra

Russell Gossman is training for the Olympics. He wants to know the distance across Lake Royal, so he can write in his training logbook how far he rows each day. If from one point on the shore to one side of the lake is 13 km and from the same point to another side of the lake ...
65. ### Math

Several cows from a Caribou Herd took 4 days longer to travel 70km to Forde Lake, than it took them to travel 60km north beyond forde lake.They averaged 5km/h less before Forde lake because the foraging was better. What was their average speed for the part beyond forde lake?
66. ### physics

A rock is dropped from a tree of height 22 m into a lake (depth 4.0 m) below. After entering the water, the rock floats gently down through the water at a constant speed of 1.4 m/s to the bottom of the lake. What is the total elapsed time?
67. ### Physics

A rock is dropped from a tree of height 20 m into a lake (depth 4.6 m) below. After entering the water, the rock floats gently down through the water at a constant speed of 1.6 m/s to the bottom of the lake. What is the total elapsed time?
68. ### chemistry

How much limestone (CaCO3) in kilograms would be required to completely neutralize a lake with a volume of 5.2 x 10^9L . The lake contains 5.0 x 10^-3 moles of H2SO4 per liter?
69. ### Math

I need to write the specified ratin as a simplified fraction. A certai lake is 1100 ft deep. A nearby lake is 300 feet deep. Write the ratio of te fist lake's depth to the second lake's depth.
70. ### Math

At a certain construction site, there is a pile containing 55 tons of sand. Four trucks, each of which holds 11.4 tons of sand, are filled from this pile. How many tons of sand remain in the pile? A. 9.4 B. 16.2 C. 20.8 D. 32.2 E. 43.6
71. ### Math

Several cows from a Caribou Herd took 4 days longer to travel 70km to Forde Lake, than it took them to travel 60km north beyond forde lake.They averaged 5km/h less before Forde lake because the foraging was better. What was their average speed for the part beyond forde lake? ...
72. ### Physics

At a height of 15 meters above the surface of a lake, a sound pulse is generated. The echo from the bottom of the lake returns to the point of origin 0.150 s later. The air and water temperatures are 20°C. How deep is the lake?
73. ### algebra

for the period 1990-2003, the amount of biscuits and pasta y(in thousands of tons) imported to the united states can be modeled by the function: y=1.36x^2+27.8x+77 how many tons obiscuits and pasta were imported to the states in 1999? in which year was the maximum imported? ...
74. ### math

Assume that water lilies double in area every 24 hours. In the spring, there is one water lily on a lake. After thirty days, the lake is completely (100%) covered with water lilies. How many days did it take for lilies to cover 25% of the lake?
75. ### Physics

You like to swim at a nearby lake. On one side of the lake is a cliff, and the top of the cliff is 36m above the surface of the lake. You dive off the cliff doing somersaults so as to have an angular speed of 6rev/min. How many revolutions do you make before you hit the water...
76. ### AP Physics

At a height of 5 meters above the surface of a freshwater lake, a sound pulse is generated. The echo from the bottom of the lake returns to the point of origin 0.140 s later. The air and water temperatures are 20°C. How deep is the lake?
77. ### Statistics

The weight of a randomly selected shipping container follows an unknown distribution with mean 12 tons and standard deviation 2 tons. Your cargo ship always carries a load of 100 randomly selected shipping containers. a. What is the probability the load weighs more than 1,231 ...
78. ### Math

Sadiq dropped his watch into a lake. The depth of the lake is 5 meters. Sadiq can dive down towards the bottom of the lake at a speed of 2 meters per second, but can swim upwards at a rate of 1 meter per second. How long will it take Sadiq to get his watch and return to the ...
79. ### Algebra

The number of bass in a lake is given by P(t) = 2800/1 + 6e^−0.05t where t is the number of months that have passed since the lake was stocked with bass. (a) How many bass were in the lake immediately after it was stocked? 400 bass (b) How many bass were in the lake 1 ...
80. ### Econ MC

Two firms, A and B, each currently dump 50 tons of chemicals into the local river. The government has decided to reduce the pollution and from now on will require a pollution permit for each ton of pollution dumped into the river. The government gives each firm 20 pollution ...
81. ### English

On the hill, there is a house. When we walk down a little, there is a lake. In that case, we can say as follows. 1. The house is above the lake. 2. The house is over the lake. 3. The lake is below the house. 4. The lake is under the house. In this case, #1 and #3 are right. ...
82. ### Science

Sometimes, when you sit by a lake in a forest, you can see perfect images of the hills and trees in the lake. Other times, when you are sitting beside the same lake, you cannot see any images in the water. Explain the difference between these two situations.
83. ### Physics

A primitive diving bell consists of a cylindrical tank with one end open and one end closed. The tank is lowered into a freshwater lake, open end downward. Water rises into the tank, compressing the trapped air, whose temperature remains constant during the descent. The tank ...
84. ### physics

A hiker determines the length of a lake by listening for the echo of her shout reflected by a cliff at the far end of the lake. She hears the echo 2.20 s after shouting. How long (in meters) is the lake?
85. ### calculus

An artificially created lake is bordered on one side by a straight dam. The shape of the lake surface is that of a region in the xy-plane bounded by the graphs of 2y=16-x^2 and x+2y=4. Find the area of the surface of the lake.
86. ### Algebra (please help me)

The cost in millions to remove x% of pollution in a lake modeled by C=6000/200-2x. What is the cost to remove 75% of the pollutant? What is the cost to remove 99% of the pollutant? For what value is this equation undefined?
87. ### Algebra

The cost in millions to remove x% of pollution in a lake modeled by C=6000/200-2x. What is the cost to remove 75% of the pollutant? What is the cost to remove 99% of the pollutant? For what value is this equation undefined?
88. ### English

1. After breakfast, we went to Mirror Lake. 2. After breakfast, we went to Lake Mirror. 3. That is Lake Ontario. 4. That is Ontario Lake. (Which one is correct? Can we use both expressions? Please check the word order.)
89. ### Finite Mathematics

I just need help with the set up of this problem, that's where I'm getting lost. A mining company operates two coal mines, M1 and M2. The company sells the coal to three purchasers: two steel mills P1 and P2, and a power generating station P3. The cost of transporting a ton of...
90. ### MATH

The tip of a plant was 6cm above a lake but a sudden wind forced the plant to move 10 cm fat from its original position and then it submerged into the lake. Find the depth of the lake upto which it was sinking. Please help!!!!!!!!!!
91. ### ECONOMICS dreadfully lost please help

Canada Honey (IN tons)/ Maple (in tons) 0 60 10 45 20 30 30 15 40 0 United States Honey (in tons)/ Maple (in tons) 0 50 10 40 20 30 30 20 40 10 50 0 the question is who has a comparative advantage in producing maple syrup and who has the advantage in producing honey.. my ...
92. ### chemistry

Oops I left a part of the question out: 2. Mercury poisoning is a debilitating disease that is often fatal. In the human body, mercury reacts with essential enzymes, leading to irreversible inactivity of these enzymes. If the amount of mercury in a polluted lake is 215 ng of ...
93. ### Linear Programming

OKay My question is: Two factories manufacture 3 different grades per paper. the company that owns the factories has contracts to supply at least 16 tons of low grade, 5 tons of medium grade, and at least 20 tons of high grade paper. It cost \$1000 per day to operate the first ...
94. ### CHemisty

Taking the mass of the atmosphere to be 5.7E15 metric tons, what mass of carbon must be burned in order to increase the average carbon dioxide level in the atmosphere by 150ppm by volume (in metric tons)? what equations do i use?
95. ### Stats ()

Coal is carried from a mine in West Virginia to a power plant in Pittsburgh in hopper cars on a long train. The automatic hopper car loader is set to put 75 tons of coal into each car. The actual weights of coal loaded into each car are normally distributed with an average of ...
96. ### Chemistry

Taking the mass of the atmosphere to be 6.0E15 metric tons, what mass of carbon must be burned in order to increase the average carbon dioxide level in the atmosphere by 110ppm by volume (in metric tons)?
97. ### chemistry

Taking the mass of the atmosphere to be 6.0E15 metric tons, what mass of carbon must be burned in order to increase the average carbon dioxide level in the atmosphere by 110ppm by volume (in metric tons)?
98. ### Physics

A bridge is 200 m long. A car weighing 2.5 metric tons is 50 m from one end of the bridge and a trucj weighing 6 metric tons is 80 m from the other end. The bridge is uniformly paved and weighs 20 metric tons. How much force does the vertical support at each end exert?
99. ### chemistry

A gas bubble with a volume of 1.0 mL originates at the bottom of a lake where the pressure is 3.00 atm. Calculate its volume when the bubble reaches the surface of the lake where the pressure is 695 torr , assuming that the temp doesn't change. I got 0.003 L, is that correct
100. ### CENE

A primary sedimentation tank that has a removal efficiency of 65% and settles out solids from a wastewater that has a SS concentration of 220 mg/L. The wastewater flows into the sedimentation tank at a rate of 2.35 million gallons per day (MGD). How many tons (as dry mass) of ...