Thursday
October 23, 2014

Posts by John


Total # Posts: 6,303

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.
April 12, 2012

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.
April 12, 2012

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.
April 12, 2012

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.
April 12, 2012

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...
April 12, 2012

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
April 12, 2012

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.
April 12, 2012

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 ...
April 12, 2012

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...
April 12, 2012

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.
April 12, 2012

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 ...
April 11, 2012

Chemistry
What 3 compunds can be used to prepare oxygen in the laboratory? What are the reactions for each of the three compounds?
April 10, 2012

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 ...
April 9, 2012

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 ...
April 9, 2012

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 ...
April 9, 2012

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 ...
April 9, 2012

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...
April 9, 2012

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?
April 9, 2012

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?
April 9, 2012

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.
April 9, 2012

math
marcie, kim and yvonne are on the same softball team. (A). During the last season . Marcie hit 3 less than twice the number of home runs that kim hit let h represent the number of home runs that kim hit . write an expression that represents the number of home runs that Marcie ...
April 8, 2012

english
1. apa 2. mla 3. apa 4. mla 5. mla 6. apa 7. apa 8. mla 9. both 10. apa are these right answers
April 8, 2012

english
Choose and Place MLA, APA, or Both in the blank. _____1. In a work with a single author, the author’s last name and initials are listed in the works cited entries. _____2. In a work with a single author, the author’s full last name and first name are listed in the ...
April 8, 2012

chemistry
@Amanda, k
April 7, 2012

Statistics
Should companies use the same confidence interval each time a confidence interval is determined or should the level change based on situations? If it changes based on situations, what type of situations might call for higher confidence levels?
April 6, 2012

Chemistry :((((
Thank you so much!!! :)))))
April 6, 2012

Chemistry :((((
explain why the bond angles found for the molecules below is as given below. Methane 109.5 Ammonia 107.5 water 104.5
April 6, 2012

english
hello?
April 5, 2012

english
alright but what structure would it be?
April 5, 2012

english
i don't know
April 5, 2012

english
i just need help on it
April 5, 2012

english
well i know its not a infinitive phase
April 5, 2012

english
its asking what grammatical structure is italicized in the sentence
April 5, 2012

english
What grammatical structure is the italicized portion of the sentence? Although her personality had not changed at all, Megan looked quite different is it: adverb clause infinitive phrase past participial phrase elliptical clause adjective clause
April 5, 2012

Chemistry
During the synthesis of Ferrocene, deprotonation of cyclopentadiene is carried out using 1,2-dimethoxyethane (DME). If the deprotonation is carried out using MeOH, will the reaction be faster or slower? Why?
April 5, 2012

Physics grade 12
A horizontal beam of alpha particles are injected with a speed of 1.3x10^5 m/s into a region with a vertical magnetic field of magnitude 0.155T. A- How long does it take for an alpha particle to move half way through a complete circle? B- If the speed of the alpha particle is ...
April 5, 2012

Economics
How might expectations of a fiscal policy being temporary weaken the effects of the policy?
April 4, 2012

Economics
How could “politics” complicate fiscal policy?
April 4, 2012

Economics
Can you please explain the problem of time lags in enacting and applying fiscal policy?
April 4, 2012

computer science
Prove that the following language is not context free: L = {a^3^n : n >= 0}
April 4, 2012

Essessentials of Communication(Speech)
I've been stuck on this question for the longest and can't find help anywhere. Instructions Read the following statement; then respond with a question, content paraphrase, feeling paraphrase, and a combination of content and feeling paraphrase. Statement from Speaker...
April 4, 2012

Government
In which type of colony did strict governors anger the colonists? A. the royal colonies B. the proprietary colonies C. the charter colonies D. the informed colonies
April 3, 2012

discrete mathematics
prove the euclid division given and int j and k>0 then one can find a unique pair (q,r) of int state j=q*k +r and 0<r<k
April 3, 2012

MATH
tree diagra probability: tree diagram with three equal parts, what is the probability, if we spin twice of getting at least one a
April 1, 2012

math
In an experiment, Marissa must select a letter card below and spin the spinner once. A B C D 1 2 3 What is the probability that Marissa's outcome will be the letter card A and the number 3 on the spinner?
April 1, 2012

Mechanics (A level), Please help
A light string of length a is attached to two points A and B on the same level and distance b apart, where b < a. A smooth ring of weight W is threaded on the string and is pulled by a horizontal force P, so that it rests in equilbrium vertically below B. Show that tension ...
April 1, 2012

Pre-Calc Helppp!!!
Use the Law of Sines to solve for all possible triangles that satisfy the given conditions. (If an answer does not exist, enter DNE. Round your answers to one decimal place. Below, enter your answers so that B1 is smaller than B2.) a = 39, c = 40, angle A = 36° angle B1...
March 31, 2012

Math
Find the Dimensions of a rectangular garden of the greatest area that can be enclosed in 40 feet of fencing.
March 31, 2012

Chemistry
Consider the cracking of gaseous ammonia at constant total pressure of 1 atm and constant temperature. Find the equilibrium gas composition at 400 degree C. Given: The Gibbs free energy for the cracking reaction 2NH3 = N2 + 3H2, DeltaGo ( delta G standard) =87,030-25.8TlnT &#...
March 29, 2012

Chemistry
Calculate the partial pressure of monatomic hydrogen in hydrogen gas at 2000 K and 1 atm pressure. Given: (i) For ½ H2 -> H, DeltaHo298=217,990 J; DeltaSo298=49.35 J/K. (ii) Assume that the heat capacity of monatomic gas to be 3/2R (iii)The heat capacity of H2 assume...
March 29, 2012

Economics
How does government intervene to move an economy out of a recession?
March 28, 2012

Economics
What does the term “recession” mean and how do we know when one occurs?
March 28, 2012

Economics
What is “Gross Domestic Product” (G.D.P.)
March 28, 2012

Economics
How might earning a college degree increase lifetime earnings and employability?
March 28, 2012

Economics
Why might an increase of the minimum wage in the United States impact unemployment rates?
March 28, 2012

physics
A sharp image is located 83.0 mm behind a 62.0 mm focal-length converging lens. Find the object distance by calculation.
March 28, 2012

probability
tommy has 7 yellows 6 green 3 blues 8 red wht it tommy probability that she will not draw a green ball
March 27, 2012

Astro
Suppose you lived on a planet with the same radius as the Earth, but it had a density 2.99 times Earth's density. Your weight would be different on this planet. Find how much you would weigh on this planet divided by your weight on Earth
March 27, 2012

Physics help please!!!
so is part a .162m
March 27, 2012

Physics help please!!!
A 2.10 kg frictionless block is attached to an ideal spring with force constant 315N/m . Initially the block has velocity -3.75m/s and displacement 0.270m . Find (a) the amplitude of the motion. (b) the maximum acceleration of the block. (c) the maximum force the spring exerts...
March 27, 2012

Chemistry
1. What is the pH of a solution whose [H3O+] is 1 X 10 -5 M? 2. What is the [H3O+] concentration of a solution with a pH of 9? 3. What is the pH of a solution whose [H3O+] concentration is 3 X 10-3 M? 4. What is the pH of a solution with a [H3O+] concentration of 1 X 10 -12 M...
March 27, 2012

math
translate to an inequality. the average speed s, was between 80 and 100 mph. translation 80 s 100
March 27, 2012

Algerba 2
how to graph 1/3 <= x <= 1/2 "<=" meaning less than or equal to.
March 26, 2012

Chemistry Help!!!!
for each of the following pairs of elements, give the correct molecular formula, explain how you arrived at this answer( you may use the Bohr model notation, or the orbital model notation, or explain linguistically) and note whether the bonding is covalent or ionic. ( I tried ...
March 26, 2012

math
15,000 down payment, 20-year mortgage loan with annual 6% interest compounded monthly. The payment is $809. Trying to figure the final selling price. I can do all the steps except for calculating P.
March 26, 2012

Chemistry
2NO(g) + H2(g) --> N2O(g) + H2O(g) + energy. 1. Assume the reaction is reversible and at equilibrium. What shifts in the equilibrium of this reaction are suggested by Le Chateliers Principle?
March 26, 2012

PHYSICS
Calculate the force required to remove a suction cup of area 2.60 cm2 from the surface to which it is stuck.
March 26, 2012

physics
A man doing a slow push-up is approximately in static equilibrium. His body is horizontal, with his weight of 755 N supported by his hands and feet, which are 1.34 m apart. One hand rests on a spring scale, which reads 270 N. If each hand bears an equal weight, how far from ...
March 26, 2012

physics
A 85.0 N weight is held in the hand. The upper arm makes an angle of 29.0° with the vertical, and the lower arm is 13.0° above the horizontal. Find the tension in the biceps tendon.
March 26, 2012

p
A newly planted tree is supported against the wind by a rope tied to a stake in the ground, as shown in the figure below. The force of the wind, though distributed over the tree, is equivalent to a single force F, as shown in the figure. Find the tension in the rope. Assume ...
March 26, 2012

physics
An artist designs a mobile of light horizontal rods connected by vertical strings and supporting various shaped weights (see figure below). Find the magnitudes w2, w3, and w4 if w1 = 4.92 units of weight. The numerical values given in the figure all have units of length.
March 26, 2012

Chemistry
85.65 grams of barium hydroxide were dissolved in 2000ml of water. 88 grams of carbon dioxide were passed through the solution producing a white precipitate. what was this white precipitate and how many grams of it were produced.
March 26, 2012

science
A merry-go-round starts from rest and accelerates uniformly over 26.0 s to a final angular velocity of 5.50 rev/min.
March 26, 2012

personal finance
14000-12000=2000
March 25, 2012

M1, Physics
Two hooks A and B are fixed to a ceiling, where AB is 2.5 m. A small object of mass 3 kg is suspended from A and B by two light inextensible strings so that it is 2 m from A and 1.3 m from B. calculate the tension in strings
March 24, 2012

Pre-Calc
A hot-air balloon is floating above a straight road. To estimate their height above the ground, the balloonists simultaneously measure the angle of depression to two consecutive mileposts on the road on the same side of the balloon. The angles of depression are found to be 24&...
March 23, 2012

Pre-Calc
Evaluate the expression without using a calculator(show work please)? (sin pi/4 cos pi/6 - sin pi/6 cos pi/4) the answer is 1/4(2-ã3)
March 23, 2012

math percentiges
If the shoes cost 80.00 and i can get 30% off how would i set that problem up?
March 23, 2012

Math
A hemisphere of radius 7 sits on a horizontal plane. A cylinder stands with its axis vertical, the center of its base at the center of the sphere, and its top circular rim touching the hemisphere. Find the radius and height of the cylinder of maximum volume. radius: height:
March 22, 2012

Math
A box has a bottom with one edge 2 times as long as the other. If the box has no top and the volume is fixed at , what dimensions minimize the surface area?
March 22, 2012

algebra
What is the sum of the first 19 terms of the series: 63 + 55 + 47 + 39 + 31 + …? I think it is 769.5 is it right?
March 22, 2012

algebra
Sara bought some 6-penny nails and some 10-penny nails at ace hardware. She bought 2 more 6-penny nails than she did 10-penny nails. She had a total of 8 nails. How many 6-penny and 10 penny nails did sara purchase?
March 22, 2012

physics
A simple Atwood's machine uses two masses, m1 and m2. Starting from rest, the speed of the two masses is 7.0 m/s at the end of 5.0 s. At that instant, the kinetic energy of the system is 100 J and each mass has moved a distance of 17.5 m. Determine the values of m1 and m2.
March 21, 2012

physics
Period: 2pi/15, or one oscillation every 15 minutes. Freq: 1/15 Equation: let d be the displacement then d = 6cos(2pi/15t)
March 21, 2012

Math
alberto has 12 quarters, 10 dimes, 10 nickels, and 20 pennies. How many different combinations of coins can he make to have $2?
March 20, 2012

MATH
WHAT IS THE BASE AREA THE BOX? L=8 IN. W=3 1/2IN AND H= 13IN.
March 20, 2012

physics
A marble cylinder that has a diameter of 42 cm and stands 1.25 m tall rests on a flat tile deck. What is the pressure exerted on the deck by the cylinder?
March 18, 2012

Physics Please help!
In each of the following cases, the mass is 7.99 kg and the radius is 7.50 cm. (a) What is the moment of inertia (kg/m2 ) of a solid cylinder rotating about an axis parallel to the symmetry axis but passing through the edge of the cylinder? (b) What is the moment of inertia (...
March 18, 2012

Math(Please help)
.0397=-39.5x x should = -.00101
March 18, 2012

Math(Please help)
is it .0015 or .015 you wrote .0015 first then .015 second. if its .0015 then its .0397 not .0262
March 18, 2012

Math(Please help)
yes
March 18, 2012

Math(Please help)
x/.025 is (1/.025)*x 1/.025=40
March 18, 2012

Math(Please help)
first put the .015 on the other side by taking it away from the other side so .0262=-40x+.5x now add the x's .0262=39.5x solve for x
March 18, 2012

math
go through each of the possibilities of getting to 11. 1+10 2+9 3+8 4+7 and so on. think of what you are looking for, twice the girls age will be four more than the boys age.
March 17, 2012

Physics Please help!
In each of the following cases, the mass is 7.99 kg and the radius is 7.50 cm. (a) What is the moment of inertia (kg/m2 ) of a solid cylinder rotating about an axis parallel to the symmetry axis but passing through the edge of the cylinder? (b) What is the moment of inertia (...
March 17, 2012

trig
In a computer simulation, a satellite orbits around Earth at a distance from the Earth's surface of 2.1 X 104 miles. The orbit is circular, and one revolution around Earth takes 10.5 days. Assuming the radius of the Earth is 3960 miles, find the linear speed (velocity) of ...
March 17, 2012

Biology
What is the role of promoter in lac operon?
March 17, 2012

Physics
Would it have been possible to make DNA a binary code?
March 17, 2012

pre-calc
Find an angle between 0 and 2ð that is coterminal with the given angle. -8pi/3 A sector of a circle has a central angle of 60°. Find the area of the sector if the radius of the circle is 3 mi.
March 17, 2012

calculus
Consider the function f(x)=3x^2 – 5x on the interval [-4,4]. Find the average slope of the function on this interval. By the mean value theorem, we know there exists at least one c in the open interval (-4,4) such that f’(c) is equal to this mean slope. For this ...
March 16, 2012

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