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September 22, 2014

Posts by john


Total # Posts: 6,248

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

math
30% of the tickets sold by a movie theater for the Friday night show were children's tickets at $4 each. The rest of the tickets were sold at the full price of $8.50. The movie theater collected $360 just for the children's tickets. How many tickets did they sell in all?
March 15, 2012

math
wat is 50% of 500?
March 15, 2012

Science
How can science be used to help discourage seagulls from attacking students during lunch?
March 15, 2012

physics
A merry-go-round starts from rest and accelerates uniformly over 26.0 s to a final angular velocity of 5.50 rev/min. (a) Find the maximum linear speed of a person sitting on the merry-go-round 4.25 m from the center. (b) Find the person's maximum radial acceleration. (c) ...
March 14, 2012

physics
Compute the linear momentum and angular momentum of a Frisbee of mass 0.175 kg if it has a linear speed of 1.65 m/s and an angular velocity of 61.5 rad/s. Treat the Frisbee as a uniform disk of radius 12.0 cm.
March 14, 2012

physics
As a bowling ball of radius 15.9 cm rolls down the alley to the right, a frictional force of magnitude 1.46 N, directed to the left, acts on it. Find the frictional torque with respect to an axis through the center of the ball.
March 14, 2012

physics
As a bowling ball of radius 15.9 cm rolls down the alley to the right, a frictional force of magnitude 1.46 N, directed to the left, acts on it. Find the frictional torque with respect to an axis through the center of the ball.
March 14, 2012

math
If 15 marbles are 3/5 of the marbles in a bag. how many are in the bag?
March 13, 2012

Maths
I am a 2 digit number .the sum of my digits is 9.i am divisible by 5 and smaller than 50. What is my number
March 13, 2012

trig
5sin(2x)+4cos(x)=0
March 12, 2012

trig
5sin(2x)+4cos(x)+0
March 12, 2012

math geometry
a rectangle has an area of 104 cm square? if the lenght is 3 cm less than twice the width what is the length of the rectangle
March 12, 2012

Finance
Firm A has $10,000 in assets entirely financed with equity. Firm B also has $10,000 in assets, but these assets are financed by $5,000 in debt (with a 10 percent rate of interest) and $5,000 in equity. Both firms sell 10,000 units of output at $2.50 per unit. The variable ...
March 12, 2012

Math
4*(z)=1/4*(y)
March 12, 2012

Trigonometry
first you would want to convert feet to miles or vice versa. Then, youll want to build the triangle because you start at 40,000 feet and then that goes at a six degree angle along the x axis for 20 miles. So you will want to put this on a cartesian plane because from there you...
March 11, 2012

Trig.
finnd a possible measure of the angle drawn in standard position that passes through the points (ã2,-ã2)
March 11, 2012

english
What is the underlying message of all of Arthur Jarvis’s writing? How does reading his son’s writing affect the behavior of James Jarvis?
March 10, 2012

Math(Thank you for your help)
P.E.M.D.A.S
March 9, 2012

trig
120, 240, and 300
March 9, 2012

Trig
my mistake, I forgot to put the 4 underneath the sq root of 15
March 9, 2012

Trig
cos(x)=(4^2-1^2)^(1/2). If your csc=4, then build your right triangle and if csc(x) is hyp/opposite, then you should get what i have put above. Hope this helps
March 9, 2012

calculus
Estimate the volume of the solid that lies below the surface z = xy and above the following rectangle. R = (x, y)|8 ≤ x ≤ 14, 4 ≤ y ≤ 8 Use a Riemann sum with m = 3, n = 2, and take the sample point to be the upper right corner of each square. (b) Use ...
March 9, 2012

math
Ethan , Marta , and Roscoe found a large aluminum ring, 10 feet in diameter, in a field about 100 feet behind Ethan's house.They estimated the number of complete revolutions that the ring would take if they rolled it to the house. Ethan estimated 10 revolutions, Marta ...
March 8, 2012

Economics
Why is there such a wide variety of desired goods and services in a market?
March 8, 2012

Economics
Help Please! How does self-interest help achieve society’s economic goals?
March 8, 2012

physic
A long straight horizontal wire carries a current = 3.90 A to the left. A positive 1.00 C charge moves to the right at a distance 1.50 m above the wire at constant speed v = 5000 m/s. What is the magnitude of the magnetic field at the location of the charge due to the current-...
March 8, 2012

Chemistry
How much heat is associated with the burning of 2.27 g of methane in the following unbalanced reaction: CH4(g) + O2(g) →CO2(g) + H2O(g)?
March 7, 2012

Chemistry
Given the following hypothetical equations, 2A + B → 3C + 2D ΔH = -46.7kJ C → B ΔH = 13.1kJ 2E → B ΔH = 84.5kJ, what is the enthalpy change (kJ) for the following reaction? A → D + 2E
March 7, 2012

Chemistry
Thanks for all the help Bob!
March 7, 2012

Chemistry
The molar mass of an unknown salt is 63.5. If 4.81 g is added to 81.1 mL of water the temperature changes from 20.95oC to 21.62oC. What is the molar heat of solution (J/mol) of the salt? (Assume all of the heat is transfered to the water) Express your answer to the nearest ...
March 7, 2012

Chemistry
What kind of orbital is designated by the quantum numbers (3,1,1,1/2)? Answer s, p, d, or f only.
March 7, 2012

math
123/3=41. 41*2=82 students
March 7, 2012

4th grade math
4 out of 5 because there are 5 total marbles, and 4 are blue. Thus the probability is 4/5. Your answer should be d. not here.
March 7, 2012

Biology
Try a bar graph with type of medication on the y axis and time in hours on the x axis. Your bars will be horizontal.
March 7, 2012

US HISTORY
Thank u very much
March 7, 2012

US HISTORY
thank u, are there any others because my teacher said almost 5 of em
March 7, 2012

US HISTORY
How does Prohibition on alcohol during the 1900's affect today life
March 7, 2012

calculus
If 0 degrees < x < 180 degrees, what values of x, to the nearest degree, are the solution to the equation 2tan to the square x + 5tanx - 12 = 0
March 7, 2012

calculus
For part B, your figure there is an ellipsoid, x^2+y^2+z^2=4, so the domain should be (x,y,z):X<4,y<4,z<4
March 7, 2012

calculus
f'(x)=3x^2+2xy^2+1 f'(Y)=2x^2+3y^2+1 f'(xy)=4xy f'(yx)=4xy
March 7, 2012

Math
You are correct on the time, but it needs to be simplified if not put into decimal form. Now you need to plug in 2 into the orignal problem and get a resultant, then plug in three to the original problem as well. If they are the same resultant then they follow rolles theorem. ...
March 7, 2012

Chemistry
If 14.0 kilograms of Al2O3(s), 57.4 kilograms of NaOh(l), and 57.4 kilograms of HF(g) react completely, how many kilograms of cryolite will be produced?
March 6, 2012

Calculus-derivatives
Yes for both. Growth and decay problems are awful, just letting you know
March 6, 2012

math
Plug 10 into the x value. f(10)=7(10)+8 F(-6)=7(-6)+8 and so on...
March 6, 2012

calculus
dy/dx= [5x^4e^(x^4)+4x^3*e^(x^4)*5x^4]* [(x^5)(e^(x^4)]
March 6, 2012

Singapore Math
still confused
March 6, 2012

Pre-Cal
Get you a ti-83 and graph it...should show you all of this
March 6, 2012

Calculus
Since you have found your derivative you then need to move on and find its critical values(where the derivative equals zero). Then if those numbers are within the interval [1,4] you must also plug those into your orignal function. If they do not, then they should be ...
March 5, 2012

Trig
(sinxcosy+cosxsiny)(sinxcosy-cosxsiny)= Then, foil those and your middle two terms should cancel out leaving you with sin^2xcos^2y-cos^2xsin^2y= now using the pythagereom theorem change all the sin^2's to cos^2 giving you cos^2y-cos^2xcos^2y-[cos^2xcos^2xcos^2y]= cos^2y-...
March 5, 2012

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