Wednesday
April 16, 2014

Posts by john


Total # Posts: 6,089

physics
during a process, 21.6 MJ of heat is added to closed system. if the internal energy is increased by 59.6 MJ, how much work in Btu was done? is the work done on ro by the system?

algebra 2
by gruoping...!!

phi 103
I brought a pair of shoes from that store that immediately fell apart. their shoes are no good. Does this falls under Begging the question fallacy?

Chemistry!!
1) Write balanced chemical equation for the oxidation of Fe^2+(aq) by S2O6^2-(aq)? 2)Write balanced chemical equation for the oxidation of Fe^2+ by N2O 3)Write balanced chemical equation for the oxidation of Fe^2+ by VO2+

math
Solve this system using elimination. If a single solution exists, write the solution as an ordered pair. Your answer will be an ordered pair, no solution, or infinitely many solutions 3a+5b=-19 5a-27b=145

English II - Animal Farm
My assignment is to find the human vice that each of the seven commandments intended to prevent in the novel, Animal Farm. First, I do not know what human vice the following two are supposed to prevent: Whatever goes upon two legs is an enemy. Whatever goes upon four legs, or ...

math
how long will $600K last, assuming it earns 6% a year with a withdrawl of 4% annually and inflation rate of 2%

math
Name the point of intersection for the following system, if it exists. Your answer will be an ordered pair, no solution, or infinitely many solutions. 4x-3y=-3 3x-y=-6

PHYSICS
a uniform stick weighing 50Newton is suspended from the ceiling while the other end of it rests on the floor and making an angle 60degree along with horizontal. the string makes a 15 degree angle with the vertical. find the minimum value of the coefficient of static friction t...

physics
a person 0f mass m = 60 kg walks along the radius from the periphery to the center of a circular platform of moment of inertia= 200kgm square and radius r = 3m. the disk is a rotating frictionless with angular velocity= 0.3 rad\s.find the angular velocity of the system when th...

Chem
If 20.0 L of a gas is cooled from 373 K to 273K, what is the new volume?

english
hey I'm a 9th grader and my english teacher give me a summative homework about rumors. He need us to write a problem that happen in school and also want us to answer or solve the problem about rumors.. I need help with it because I know nothing about rumors..

math
Name the point of intersection for the following system, if it exists. 4x – 3y = -3 3x – y = -6

@elena
nvm, i did it wrong. i already got the answer its 79% thanks

@elena
thank you so much help with the problem. i have trouble solving part b of the problem you helped me with. it told me to give it as a percentage, I got 10% but it is wrong. can you please help me Superman must stop a 190-km/h train in 180m to keep it from hitting a stalled car ...

college physics
i got it its 79% i was label some of the numbers with the wrong variables. tahnks and will keep that in mind

@elena Question !
for part b, what would be the percentage. i got 10% but it isnt right

college physics
Superman must stop a 190-km/h train in 180m to keep it from hitting a stalled car on the tracks. part a)If the train's mass is 3.8×10^5kg , how much force must he exert (find the magnitude)? part b)Compare to the weight of the train (give as %). partc) How much force...

uniben
do it urself

math
expand as a binomial series (r-p)^9

math
An exam consists of two parts, Section X and Section Y. There can be a maximum of 80 questions. There must be at least 20 more questions in Section Y than in Section X. Write a system of inequalities to model the number of questions in each of the two sections. Then solve the ...

math
When a person is swinging the amplitude (the swings"s distance above it's rest position) increases with each pump. According to Scientific magazine the amplitude increases by adding a constant when the person pumps sitting down, and by multiplying by a constant when t...

chemistry
(ppm and ppb are sooo not easy for me to get)c A saturated solution of PbCO3 contains 0.00011 g PbCO3 in 100. g of water. What is this concentration in parts per million?

chemistry
Most community water supplies have 0.50 ppm of chlorine added for purification. What mass of chlorine must be added to 134.0 L of water to achieve this level? anwser grams

chemistry
A sample of water is analyzed and found to contain 18.6 ppb of arsenic. If a person were to drink 2.0 L of this water per day for 1.4 years, what is the maximum amount of arsenic they could accumulate in their body? Assume that 1 year = 365 days anwser________ grams or arsenic

biology
1,Why do autotrophs always occupy the lowest level of ecological pyramids? 2.Explain how the growth of one population can bring about the disappearance of another population during succession? 3. Describe some common plants and animals from a tropical rain forest and a grassla...

chemistry
4NH3(g)+5O2(g) yield 4NO(g)+6H2O(g) Deduce the equilibrium constant expression for the reaction.

Chemistry
A 2.7 M solution of phosphoric acid (H3PO4) is to be reacted with a 7.5 M solution of sodium hydroxide to make sodium phosphate and water. How many L of the H3PO4 solution will react with 0.662 L of the NaOH solution

life orintation
8 ways in which the environment impacts communities

Mechanics problem - Newtons laws - resultant force
I have this mechanics problem. Please help me solve it. Rory, Aurora and Raoul are three lions fi ghting over a piece of meat of mass 12 kg. Each lion exerts a horizontal pull. Rory pulls with a force of 800 N. Aurora, who is 120degrees to Rory's right, exerts a force of 4...

l.o
identify and describe one environmental proble that causes ill health,accidents,crises,and disasters within your community or any other community within south africa or globally

calculis
Find the equation of the tangent line to the curve y=e^2x + 4x at the point (0,1)

calculus
Find the equation of the tangent line to the curve y=e^2x + 4x at the point (0,1)

math
a cubical container is half filled with water if the volume of water in the container is 500cm3 find the length of one edge of container?

math
a rectangular tank has the measurement 60cm wide and 2000cm2 water flows into the tank at the rate of 8 liters per minutes how long will it take to fill the tank?

math
a rectangular swimming pool is 30m wide and 50m long if the 600m of water is added to the pool what is the increase in the height of the water level in centimeters?

math
A rectangular box is 16cm long and 10cm wide 960 1-cm cubes can fit into the box exactly what is the height of the box?

Physics
Anyone else from SF have to google this question, or was i the only one?

pre-calc helpppp
Find sin x/2, cos x/2, and tan x/2 from the given information. (show work please) thank you!!! cos x = − 4/5, 180° < x < 270°

pre-calc helpppp
thank you so much!!!!

pre-calc helpppp
Simplify the expression by using a Double-Angle Formula or a Half-Angle Formula. ã((1-cos50)/2)

pre-calc helpppp
Thank you!!!!

pre-calc helpppp
Evaluate the expression under the given conditions (show steps please) sin(è/2); tan è = − 5 / 12 , è in Quadrant IV

Chemistry!! Help
Consider the following equilibrium: N2O4 <=> 2NO2 You may assume that delta H and delta S do not vary with temperature. At what temperature will an equilibrium mixture of 1 atm total pressure contain twice as much NO2 as N2O4?

Chemistry!!!
Consider the rxn during the Haber Process: N2 + 3H2 ---> 2NH3 The equilibrium constant is 3.9 x 10^(5) at 300 K and 1.2 x 10^(-1) at 500 K. Find Delta H reaction and Delta S for reaction

MATH##$$&&^^**
4.16%

Physics
Thanks Elena your a life saver :)

Physics
A cube of ice is taken from the freezer at -8.8°C and placed in a 103 g aluminum calorimeter filled with 321 g of water at room temperature of 20°C. The final situation is observed to be all water at 15°C. What was the mass of the ice cube? Could someone please hel...

math
6/8

math
The water in fish tank has evaporated so it was 5/8 inch below the level it should be they added water and the water level went up 3/4 inch did the water level end up above or below where it should be

science
Which of the following scales use the concept of absolute zero? I. C II. F III. K IV. R

science
Thermal energy is different from temperature because thermal energy depends on the _____.

science
A trash can is rolling down the street at 5 m/s. If the trash can has a mass of 23 kg, what is its momentum?

chem
Brandon throws a flying disc with a force of 8 N. If the disc has an acceleration of 4 m/s2, what is the mass of the disc?

science
Brandon throws a flying disc with a force of 8 N. If the disc has an acceleration of 4 m/s2, what is the mass of the disc?

english
thank you and for this one: Meredith is to be restored as captain.the infinitive is to be and is a noun?

english
so it is to use and it would be a adverb

english
okay and the second one is i have permission and its a adverb?

english
okay and the answer can only be a noun.adverb or adjective.

english
i have one more question what is the function of the italicized infinitive phrase ins the sentence. 1.I want to go with you to the store. 2.May I have permission to use the car tonight?

english
thank you ms.sue

english
what is the gerund phrase and the noun function of the gerund in the sentence 1.Her favorite pastime is entertaining friends.

Math
A math teacher is randomly distributing 15 rulers with centimeter labels and 10 rulers without centimeter labels. What is the probability that the first ruler she hands out will have centimeter labels and the second ruler will not have labels.

physics- help please !!1
A toy rocket moving vertically upward passes by a 2.2m -high window whose sill is 7.0m above the ground. The rocket takes 0.17s to travel the 2.2m height of the window part a) what was the launch speed of the rocker ? assume the propellant is burned very quickly at blastoff pa...

physics
15.5

Chemistry 1201
Thanks so much!

Chemistry 1201
Butane, C4H10, is a component of natural gas that is used as fuel for cigarette lighters. The balanced equation of the complete combustion of butane is 2C4H10(g)+13O(g)-> 8CO2(g)+10H2O(l) At 1.00 atm and 23C , what is the volume of carbon dioxide formed by the combustion of...

Chemistry 1201
Butane, C4H10, is a component of natural gas that is used as fuel for cigarette lighters. The balanced equation of the complete combustion of butane is 2C4H10(g)+13O(g)-> 8CO2(g)+10H2O(l) At 1.00 atm and 23C , what is the volume of carbon dioxide formed by the combustion of...

Chemistry 1201
When heated, calcium carbonate decomposes to yield calcium oxide and carbon dioxide gas via the reaction CaCO3(s)->CaO(s)+CO2(g) What is the mass of calcium carbonate needed to produce 53 L of carbon dioxide at STP?

Pre-Calc Help!!!!!!!!!!!!!!!!1
can someone help me please????

Calc Help!!!!!!!!!!!!!!!!1
tan(sin^-1(5/6)-cos^-1(1/5)

Math
Try 868

physics
An athlete thtrew a short put of mass7.52kg through a distance of 24m when we projected a short put at angle of 30. Assuming there is no air resistance, what is the initial kinetic energy of the athlete.

psyc355
30.9

psyc355
Children below the 30th percentile (in the bottom 30%) are in need of special assistance prior to attending school. What raw score marks the cut-off score for these children?

Chemistry!!!
What is the solubility of MnS, in grams per liter, in a buffer solution that is 0.120 M HC2H3O2 - 0.490 M NaC2H3O2? For MnS, Kspa=3x10^7.

Chemistry!!
A solution has [Al^3+]=8.0×10−2 M and [HC2H3O2]= 1.10 M. What is the maximum quantity of NaHC2H3O2 that can be added to 200.0 mL of this solution before precipitation of Al(OH)3 begins?

Accounting
At the beginning of April, Owl Corporation has a balance of $12,000 in the Retained Earnings account. During the month of April, Owl had the following external transactions. 1. Issue common stock for cash, $10,000. 2. Provide services to customers on account, $7,500. 3. Provid...

physics
Calculate the internal energy of 25.0 g of low-density oxygen gas (O2) at a temperature of 255 K.

Physics
a.) P=P initial + pgh 101,000 Pa + (1000)(9.8)(2.5) P=125500Pa. P=F/A 125500=F/50 6.3*10^6N

Chem...
1) what is the density of methane (CH4) at a temp. of 20C and a pressure of 684mm. 2) a gas has a density of 2.5g/L at a temp. of 20C and a pressure of 1.1 atm. what is its molar mass.

Math
As a fraction it is 60/100 but you probably need to simplify it so find a common factor of both, in this case the number 20, and divide both 60 and 100 by that to get the fraction of 3/5. 60% is equal to .6 because 100% equals 1.

Physics
The formula to use is c=f*lambda where c equals speed of a wave, f is frequency, and lambda is the Greek for wavelength. So to find the speed you multiply 9 by .654 and the answer should be 5.886 m/s.

math
I believe to find the sum of the exterior angles of a n-sided polygon is (n-2)*180 where n is the number of sides. So for a 50-sided polygon it should be 8640 degrees. For the interior angles it is (n-2)*180/n where again n is the number of sides.

Math
For a line to be perpendicular to another line you need to use m in the linear equation of y=mx+b and find the opposite and reciprocal of that number. In this case m is 3 so the opposite of 3 is -3 and the reciprocal is just flipping the fraction of -3/1 so it is now 1/-3. Now...

Physics
Where must an object be placed to have a magnification of 3.74 in front of a converging lens of focal length 14.1 cm? Answer in units of cm

Science
D because mechanical energy is basically kinetic energy and when that is greater than the force of gravity then it will not fall down.

Physics
Three identical small Styrofoam balls of mass 1.53 g are suspended from a fixed point by three nonconducting threads, each with a length of 56.4 cm and negligible mass. At equilibrium the three balls form an equilateral triangle with sides of 31 cm. What is the common ch...

algebra
For the area of a circle is πr² as you stated so all you do is set 400 equal to πr² and solve for r. 400=πr²/π 127.32=r² √127.32)= r r=11.3 Same thing for this except you use 800 instead of 400 so. 800=πr² 254.64=r² ...

math
You have 7 red marbles and 5 green marbles in a bag. You select one, do not replace it then select another. Find P(red,red) and P (green,green). Write probabilites as a percent and rounded to the nearest whole percent. Find P(red,green) and P (green,red). Compare.

Physics
Three identical small Styrofoam balls of mass 1.53 g are suspended from a fixed point by three nonconducting threads, each with a length of 56.4 cm and negligible mass. At equilibrium the three balls form an equilateral triangle with sides of 31 cm. What is the common ch...

Chemistry
What 3 compunds can be used to prepare oxygen in the laboratory? What are the reactions for each of the three compounds?

College Algebra
Annual profit in thousands of dollars is given by the function, P(x) = -.1x^2 + 50x - 300, where x is the number of items sold , x >= 0. 1.describe the meaning of the number -.1 in the formula. 2.describe the meaning of the number -300 in the formula. 3.find the profit for ...

physics
A down jacket has a surface area of 0.82 m2 and is filled with a 3.8 cm thick layer of down, which has a thermal conductivity of 6.0 10-6 kcal/(s · m · C°). The coat is worn by a person whose skin temperature is maintained at 27° C. The outer surface of t...

physics
The sun is 1.5 1011 m from the earth. (a) Over what surface area is solar radiation spread at this distance? (b) What is the total power radiated by the sun? (The sun delivers energy to the surface of the earth at a rate of approximately 1400 W/m2.) (c) Treating the sun as a b...

physics
A pot containing 1.09 liter of water, initially at 18°C, is placed on a 1101 W electric heating element. (a) How much heat must be supplied to the water to bring it to a boil? (b) How much heat is necessary to boil all the water away? What is the minimum time required to b...

Financial Math
Suppose that you decide to lease a car. At the end of the 48-month lease period, you need to make a lump-sum payment of $5000 if you want to keep the car. You decide to save up, just in case you decide to keep the car; if you don’t keep this car, you will still have saved...

physics
A 55.0 g ice cube, initially at 0°C, is dropped into a Styrofoam cup containing 318 g of water, initially at 18.2°C. What is the final temperature of the water, if no heat is transferred to the Styrofoam or the surroundings?

physics
How much energy expressed in units of food Calories (that is, kilocalories) is required to operate a 100 W light bulb for 14.70 hours?

physics
(a) How much heat is required to raise by 12.40°C the temperature of 1.4 kg of water. (b) How much heat is required to raise by 12.40°C the temperature of 1.4 kg of iron.

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