# 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....

**About Chemistry**

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

**4th grade**

Hi

**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

**9th grade English**

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

**8th grade algebra**

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.

**6th grade Language Arts**

We made a compromise

**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}

**8th grade**

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 ...

**math 8th grade**

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)

**10th grade algebra**

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

**chemistry**

12

**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**

anyone know the answer?

**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?