# Posts by Ben

Total # Posts: 1,001

calculus
Use the function defined below to calculate the indicated derivative. f(t)= 4/(t^3)+3 what is f''(2) (second derivative) Need help!!

CHEM
oops, thanks for the help!

CHEM
The vapor pressure of pure water at 25 °C is 23.8 torr. Determine the vapor pressure (torr) of water at 25 °C above a solution prepared by dissolving 35 g of urea (a nonvolatile, non-electrolyte, MW = 60.0 g/mol) in 75 g of water. where have i made a mistake? 35g/60=0....

The vapor pressure of pure water at 25 °C is 23.8 torr. Determine the vapor pressure (torr) of water at 25 °C above a solution prepared by dissolving 35 g of urea (a nonvolatile, non-electrolyte, MW = 60.0 g/mol) in 75 g of water. im not sure about the steps for ...

Chemistry
Calculate the amount of heat required to raise the temperature of a 54 g sample of water from 5°C to 20.°C.

math
0.331,0.332,0.333

Chemistry
What is the formula of a substance that contains 0.0920 g of C and 0.0180 g of H?

math
One of the angles of a right triangle measures 30°, and the hypotenuse is 10 inches long. How long is the side opposite the 30° angle?

geometry
The side of a triangle opposite a 58° measures 15 inches. To the nearest hundredth of an inch, what is the length of the side opposite a 53° angle

Calculus
No. I have no idea how to do this. I did part a and part be right but i cant do this part c

Calculus
Compute the average velocity over time intervals [4, 4.01] , [4, 4.001] , [4, 4.0001] , [3.9999, 4] , [3.999, 4] , [3.99, 4] . Use this to estimate the object's instantaneous velocity at t=4 V(4) = ???? ft/ec How do i even approach this problem?

Calculus
How do I find the instantaneous ROC at x=1.5

English (E-mail Writing)
Thanks a ton for the link, I really appreciate it!

English (E-mail Writing)
Oh wow, thanks a lot. I guess I was looking for something longer, because her e-mail was a good 6 paragraphs or so. When writing these sorts of e-mails, is there a trick to make it seem more formal and not informal?

English (E-mail Writing)
I want to do some research with a professor on campus, but I'm having a lot of trouble composing this e-mail. She sent me a long e-mail with stipulations for joining her lab and at the end it basically says "If you agree to all this, let me know and we'll set up a...

college math213
Try putting the parentheses around two numbers and figure out what you get. Don't forget that you do operations in parentheses first. For example: 16-7+5=4 You could do: (16-7)+ 5 = 4 OR 16-(7+5) = 4 Which one would be right?

Physics
A machine carries a 4.5 kg package from an initial position of di = (0.50 m) + (0.75 m) + (0.20 m) at t = 0 to a final position of df = (7.60 m) + (12.0 m) + (7.30 m) at t = 11 s. The constant force applied by the machine on the package is F = (2.00 N) + (4.00 N) + (6.00 N...

math
(x^4 - 8x^2 + 15) = (x^2-3)(x^2-5) so there will be a (x^2-3) term in the numerator and denominator that will cancel leaving (x^2-5)

Pythagorean Theorem
40 cm

ap chemistry
yeah sorry

ap chemistry
The vitamin niacin can be isolated from lover, yeast, milk, and whole grain. Which source would be the best for a multivitamin tablet

algebra
if x varies inversely as w, and z=40 when w=.06, fine z when w=20

american government
2. In federalism, the national government (Points : 1)

physics
Two packages at UPS start sliding down the 20° ramp shown in Figure P8.25. Package A has a mass of 3.5 kg and a ­coefficient of friction of 0.20. Package B has a mass of 10 kg and a coefficient of friction of 0.15. How long does it take package A to reach the bottom?

Computer Science JAVA FUNCTIONS
Write a Function You will be given one of the following problems to solve using and writing Python functions. Given a list of words, return an array which indicates the frequency that each letter occurs. For example, in the list [”apple”, ”bob”], [ ’a...

computer science
Hey I have three questions with creating these methods can any of you guys write an example code for this? Thanks Write a Function You will be given one of the following problems to solve using and writing Java functions. 1. Given a list of words, return an array which ...

computer science
Hey I have three questions with creating these methods, thanks. Write a Function You will be given one of the following problems to solve using and writing Java functions. 1. Given a list of words, return an array which indicates the frequency that each letter occurs. For ...

algebra
length and width of a rectangle A=198 in width =x length =x+7

physics
The potential energy stored in the compressed spring of a dart gun, with a spring constant of 36.00 N/m, is 0.880 J. Find by how much is the spring is compressed.

physics
The potential energy stored in the compressed spring of a dart gun, with a spring constant of 36.00 N/m, is 0.880 J. Find by how much is the spring is compressed.

physics
The potential energy stored in the compressed spring of a dart gun, with a spring constant of 36.00 N/m, is 0.880 J. Find by how much is the spring is compressed.

geometry
the slope of a line that is perpendicular to (2,4) and (-1,0) is

economics
Suppose velocity is stable, What would the Federal Reserve need to know in order to keep output at its natural level following a supply shock?

phys101
The heat-energy needed to produce any temperature change in the liquid is: DeltaH = mass x heat-capacity x DeltaT where DeltaT is the change in temperature. The heat-energy needed to melt the ice is: Hmelting = mass x heat-of-fusion Lets assume the final temperature is 'T...

algebra
The answers are all coordinates in this format: (x,y) The first equation y=0, means that the answer looks like this: (x,y=0) or (x,0) If y=0, you can replace y in the second equation so you get x=0+2=2 So x=2. Answer: b) (x=2,y=0) or (2,0)

science
Describe the bonds that "un-zip" during the replication of dna.

science
Describe the bonds that "un-zip" during the replication of dna.

Trig
654.7

Phsyics Waves
Look it Up

you need an apostrophe on "Tybalts" in the last line. Nice job

exponent of 1000

american intercontinental university
The fresh water should taste sweet because of the sugar residue left in your mouth

Algebra
2x-6y<18 when I change this to the other form I get y>-2/6+(-3)but when I graph it all the points come out = to instead of > than. What am I doing wrong.

chemistry
Thank you very much for your time.

chemistry
Nitroglycerine decomposes according the the equation: 4C3H5(NO3)3 -> 12 CO2 + 10 H2O +6N2 + O2. 15.0 g of nitroglycerine is placed in a 500 ml flask at 25.0 C. The vapor pressure of water at this temperature is 23.8 mmhg. Find the total pressure in the flask after the ...

physics
rofl do you go to W-L?

Physics
A neutron collides elastically with a helium nucleus (at rest initially) whose mass is four times that of the neutron. The helium nucleus is observed to rebound at an angle θ'2 = 44° from the neutron's initial direction. The neutron's initial speed is 7.0 ...

Physics
A neutron collides elastically with a helium nucleus (at rest initially) whose mass is four times that of the neutron. The helium nucleus is observed to rebound at an angle θ'2 = 44° from the neutron's initial direction. The neutron's initial speed is 7.0 ...

math algegra
one type of probablity used practically daily is?

Math
how do you solve: 2A^2-7a-15

Mathematics
Thanks. i worked it out and it came out to = 4 liters

geography
what is china's culture? please give examplesa Thank you!

Chemistry
A sample of .234g of carbon is placed in a closed stainless steel bomb with .502g of of oxygen gas. The mixture is ignited giving of carbon dioxide. How many grams of carbon dioxide should be obtained upon combustion?

Finance
John borrowed \$1,000 discounted at 10% for six months. How much did he receive when the loan was made? I get \$952.38 by using the formula below: 1000=P(1+.10/2)^(.5*2) - am I doing this right?

Finance
Determine the amount of each payment to be made to a sinking fund in order that enough money will be available to pay off the following loan. \$29,000 loan, money earns 12% compounded annually, 42 months. I tired doing this using the future value of an ordinary annuity formula...

Economics
This chart shows the components of nominal GDP for the years 2000 and 2001. All figures are in billions of current dollars. Components 2000 2001 Consumption \$6,684 \$6,987 Investment \$1,755 \$1,560 Government Spending \$1,751 \$1,858 Exports \$1,101 \$1,034 Imports \$1,467 \$1,383 ...

Economics
What percentage of GDP in 2000 is consumption

Math (repost)
In standard form, find the equation of the circle that passes through the origin and x-intercept 1 and y-intercept 2. (I fixed a correction a little too late after a response.) Help please? thanks!

Physics
Calculate the speed needed by a spacecraft to maintain a circular orbit at about 350 km above Earth’s surface. (it's a project where we create our own spaceship. let's say the craft is 500kg) --- Not sure about the formula to find this. All I know is that it may ...

Math
woah, oops. the y-intercept is 2.

algebra
You can work a total of no more than 34 hours per week at your two jobs. House cleaning pays \$8 per hour and your sales job pays \$6 per hour. You need to earn at least \$245 per week to cover your expenses. Write a system of inequalities that shows the various numbers of hours ...

chemistry
0.115

math/probability
the anwser is 4

ecology
hawk

Pre-algebra
nope,I'm not very good in math as well :(

Social Studies
What is the Socratic Method?

Pre-algebra
hi,are you good at World History?

Social Studies
Um excuse me,could you help me with this one problem I have?I don't understand it

science
Hi, quick question: Graphite is burned in oxygen to give carbon monoxide and carbon dioxide. If the product mixture is 33% CO and 67% CO2 by mass, what is the heat from the combustion of 1.00 g of graphite? dH values: CO:-110.5 kj/mol, CO2: -393.5 kj/mol Thanks!

Calculus
Use linear approximation, i.e. the tangent line, to approximate 8.4^(1/3) as follows: Let f(x)= x^(1/3) . The equation of the tangent line to f(x) at x=8 can be written in the form y=mx+c where m=1/12 and c=4/3: Using this, find our approximation for 8.4^(1/3).

AP Chem
This post helped immensely, thank you so much and merry Christmas!

science
which of earth's spheres extends into all others

Math
Use linear approximation, i.e. the tangent line, to approximate sqrt[3] { 8.4 } as follows: Let f(x) = sqrt[3] x. The equation of the tangent line to f(x) at x = 8 can be written as y=mx+c where m=1/12 b=4/3 find the approximation for sqrt[3] {8.4}

Please Help Me. I'm doing a Science Fair Project, and I need help with finding simmilar experiments to mine. My experiment is: Which saliva is cleaner: Cat, Dog, or Human???

world history
why did the industrialized nations of the world embark so aggressively upon imperialist ventures between 1880 and 1914?

Physics (Rotational Kinetic Energy)
Hello, The question is: A solid ball rolls along the floor with a constant linear speed v. Find the fraction of its total kinetic energy that is in the form of rotational kinetic energy about the center of the ball. Krot/Ktotal = ? The answer I keep getting is 3/1, but the ...

psychology
It also depends on the habituation of the stimulus. Rather than conditioned excitation, you would get conditioned inhibition here.

Biology
How is the expression of sex-linked genes similar and different from the expression of autosomal genes?

Biology
How is the expression of sex-linked genes similar and different from the expression of autosomal genes?

french
YOU legs hurt?

English
free verse does not mean don't use needed punctuation or capitalization. As I searched for examples of free verse, I found many that didn't have punctuation (which caused ideas and thoughts to run together) and didn't have capitalization, which distracts from the ...

Biology
I am having trouble descibing how the expression of sex-linked genes is similar and different from the expression of autosomal genes?

economics
Suppose that the government decides to charge cola consumers an excise tax. Before the tax, the market is in equilibrium, where 12 million cases of cola are sold every month at a price of \$3.50 per case. After the tax, 6 million cases of cola are sold every month; consumers ...

72/100=x/200 **cross mulitply: 100x=72*200 100x=14400 x=14400/100 x=144 ______ Or just multiply .72 by 200 .72*200=144

Physics (Normal Force)
When a book weighing 10 N is placed on a table, the table exerts a normal force of 10 N on the book. When a crate weighing 250 N is placed on the same table, the table exerts a normal force of 250 N on the crate. Explain the mechanism that allows the table to exert just the ...

calculus
how do you solve e^(9ln2)

7x-15y+9=0 **Subtract 9 from both sides 7x-15y=-9 **Subtract 7x from both sides -15y=-7x-9 **Divide both sides by -15 y=(7/15)x+(9/15) <--- equation isolate for y

biology
What do you think?

Math (Angle Calculation)
Would -75.74 degrees be the same as 284.26 degrees?

math
Could you tell me how exactly to graph piecewise functions.

Physics

pchem
Use R = 8.2 × 10–5 m3 atm/mol K and NA = 6.02 × 1023 mol–1. The approximate number of air molecules in a 1 m3 volume at room temperature (300 K) and atomospheric pressure is: 41 450 2.5 × 1025 2.7 × 1026 5.4 × 1026

Chemistry College (Need to know!)
How is this Possible GK. Everywhere I have looked, including mark schemes and chemistry websites dH(solution) is worked out via this equation: dH(solution) = dH(LE) - dH(hyd) + dH(hyd) What is it you are working out with solute and solvent?

Chemistry College (Need to know!)
Am I Correct in assuming this? dH of solution = -dH of lattice enthalpy + dH of hydration E.g: dHsolution NaCl = -dHLE NaCl(s) + dHhyd Na+(g) + dHhyd Cl-(g) Units as kJmol-1

Chemistry College
Am I Correct in assuming this? dH of solution = -dH of lattice enthalpy + dH of hydration E.g: ÄHsolution NaCl = -ÄHLE NaCl(s) + ÄHhyd Na+(g) + ÄHhyd Cl-(g) Units as kJmol-1

Chemistry College
Well to be honest I wasn't there for the teaching of this in my class due to University interviews. I was just wondering how you actually work through them as other websites i have been on have all been in too much (universty standard) detail. Thank you for the fast response!

Chemistry College
Is there a simple formula for the Enthalpy of solution and/or hydration?

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