Tuesday

February 21, 2017
Total # Posts: 2,074

**chemistry**

i need help setting this problem up. i don't understand which numbers go where

*March 19, 2011*

**chemistry**

If 74.5 grams of a hot metal was added to 56.4 grams of water and the temperature of the water rose from 20.4 to 33.4 degrees, how many KJ of energy was lost by the hot metal?

*March 19, 2011*

**Differential equation- Math**

Find the general solution of the following system of equation? Please help, i don't know what to do... dx/dt = 3x +2y +2z dy/dt = -5x - 4y - 2z dz/dt = 5x + 5y +3z.

*March 17, 2011*

**amet**

substituting t=12s gives a = 2(12) - 10 = 14m/s-2 Using the formula d = Vit +1/2 at^2 d = 15(12) + 0.5 (14)12^2 d = 180 + 1008 d = 1188 meters (distance traveled) add the initial position d = 1188 + 1.8 = 1189.8 (Position of particle) I hope this is correct... :(

*March 17, 2011*

**social studies**

it say to briefly describe the events that followed the Confederate defeat at Gettysburg. (civil war). first is followed meaning before or after. and what does it mean by describe the events?

*March 16, 2011*

**science**

How do you calculate the atomic mass of magnesium? 79% magnesium-24, 10% magnesium-25, 11% magnesium-26

*March 14, 2011*

**algebra**

Tammy bought 16 cookies for a party. She had 6 cookies decorated at an extra cost of 25 cents each. If the total cost of the cookies was $9.50, how much did each plain cookie cost?

*March 13, 2011*

**Science**

What is the initial temperature? If it is just for phase change then the formula is Q = m L Q = 0.063 x 32.3

*March 12, 2011*

**Science**

Calculate the amount of heat required to completely sublime 63.0 g of solid dry ice CO2 at its sublimation temperature. The heat of sublimation for carbon dioxide is 32.3 C.

*March 12, 2011*

**Science**

Calculate the amount of heat required to completely sublime 63.0 g of solid dry ice CO2 at its sublimation temperature. The heat of sublimation for carbon dioxide is 32.3 C.

*March 12, 2011*

**Chemistry**

What is the change in internal energy of a system that releases 1275 J of heat to the surroundings and is compressed so that 235 J of work are done on the system?

*March 11, 2011*

**english**

thankyou so much that is so helpful

*March 7, 2011*

**english**

Im not sure on how to do my introduction on an essay for a school magazine giving your views on how people treat animals? can someone please help me thanks alot

*March 7, 2011*

**Geography/History**

sorry i was saying katilin

*March 7, 2011*

**ENG**

Choose the correct verb: Some people (know, Knows) more about their favorite TV characters than they do about the members of their own family. A) knows B) know

*March 6, 2011*

**chemistry**

A 6.0 L flask contains a mixture of methane, argon and helium at 45 degrees C and 1.75 am. If the mole fractions of helium and argon are 0.25 and 0.35, respectively, how many molecules of methane are present?

*March 1, 2011*

**Math**

The number of calls received by a car towing service averages 14.4 per day (per 24 hour period). After finding the mean number of calls per hour, find the probability that in a randomly selected hour the number of calls is 0

*February 27, 2011*

**calculus**

let f(x)=sqrt x+4. Calculate the difference quotient f(5+h)-f(5)/h for h=.1 h=.01 h=-.01 h=-.1

*February 24, 2011*

**PRE-ALGEBRA**

2V/5+V/4

*February 22, 2011*

**Calculus**

A retangular poster is to be made out of cardboard. The margins on the top and the bottom will be 2 inches. The margins on the sides will be 1 inch. The area of the poster devoted to the printed material must be 300 square inches. (a) to the nearest .001 inches, find the ...

*February 17, 2011*

**algebra1**

how do you slove x+3y=-30 9x-12y=3 with substitution and elimation

*February 16, 2011*

**5th grade math**

How many possible combinations for an 8-digit binary number are there? How did you get this an answer?

*February 15, 2011*

**Chemistry**

A square of aluminum foil measuring 3.20 inches on each side weighs 275 mg. The density of aluminum is 2.70 g/cm3. Find the thickness (in micrometers) of the foil.

*February 11, 2011*

**algebra 2**

find the average rate of change for the function f(x)=60x-3x^2 between x=6 and x=19

*February 9, 2011*

**science 4th grade**

Science fair projets with fish

*February 8, 2011*

**english**

where did the jim crow laws take place? and why?

*February 7, 2011*

**Calculus**

The shape is a cone. The radius is 6 cm and the height is 9 cm

*February 6, 2011*

**Calculus**

If water is poured into a cup at a rate of 1 cubic centimeter per second, how fast is the dept of the water increasing when the water is 4 cm deep? r = 6 cm h = 9 cm V = 1/3(pie) r^2 x h V = (pie)r'h + 1/3 (pie)r^2 h' 6 / 9 = r / h 6h = 9r r = 3 / 4.5 h V = 1/3(pie) (3...

*February 6, 2011*

**Calculus**

Okay, I see what I did wrong. I did dy/dt = 6 instead of dy/dt = .5. Thanks a lot

*February 6, 2011*

**Calculus**

A street light is hung 18 ft. above street level. A 6-foot tall man standing directly under the light walks away at a rate of 3 ft/sec. How fast is the tip of the man's shadow moving? I know I would've to set up a proportion. 18 / 6 = x + y / y x = distance of man from...

*February 6, 2011*

**Calculus**

Two trucks start from the same point. One truck travels due east at a rate of 50 mph and the other trucks travels due north at a rate of 60 mph. At what rate is the distance between the two vehicles increasing 1 1/2 hours later? I think the answer is 55 mph because I added 60...

*February 6, 2011*

**Calculus**

The slope is actually -5. And forget I think i understand this now.

*February 6, 2011*

**Calculus**

In the diagram below, the y-coordinate of point P is increasing at a rate of 4 units per minute while point Q remains in its fixed position. Find the rate of change of angle, in radians per minute, when y = 20. y ^ | P (0, y) | | | | |---| |___|________ Q (4, 0) Then, P (0 , ...

*February 6, 2011*

**calculus**

Your welcome. Don't worry you'll do good in your studies, keep it up

*February 6, 2011*

**calculus**

For example, √x is the same as x^1/2, the derivative of √x is 1/2^ -1/2 equals to 1 / 2√x sqrt(3x) = sqrt(3)sqrt(x) and the derivative of this is sqrt(3)*derivative(sqrt(x)) = sqrt(3)/2sqrt(x), as d/dx (sqrt(x)) = 1/2sqrt(x). now, multiply the top and bottom ...

*February 6, 2011*

**Managerial Accounting**

A food division reported cost of sales-food of $198,680. Employees' meals cost $1,225, complimentary meals $142 and transfers in were received from the bar operaton with a cost of &82. Determine the net cost of sales.

*February 6, 2011*

**alg and trig**

6x^3-5x^2+15x+5 / 2x^2-x+3

*February 2, 2011*

**science**

how do u learn the skeleton bones in one night

*January 31, 2011*

**NOUNS, PRONOUNS, AND ADJECTIVES**

is a noun to go with it

*January 29, 2011*

**Chemistry**

Calcium carbonate reacts with phosphoric acid to produce calcium phosphate, carbon dioxide, and water. 3 CaCO3(s) + 2 H3PO4(aq) Ca3(PO4)2(aq) + 3 CO2(g) + 3 H2O(l) How many grams of phosphoric acid react with excess calcium carbonate to produce 3.47 g Ca3(PO4)2?

*January 27, 2011*

**Chemistry**

I did follow those steps and they didn't work for the first problem.

*January 27, 2011*

**Math**

i don't know what you mean by infinity?? thanks for the other help (:

*January 25, 2011*

**Math**

btw, i don't know if i should switch the sign (greater than or less than) or if it should be negative! thank you

*January 25, 2011*

**Math**

i have no idea!!!!!

*January 25, 2011*

**Math**

-1/4k is greater than 18

*January 25, 2011*

**math in topics**

Wait time for a counselor is 60 minutes. There are five counselors and each counselor see a student for an average of 30 minutes per day. How many new counselors are needed to shorten the wait time to 15 minutes? Each counselor see 5 students per day totaling 25 students

*January 25, 2011*

**math in topics**

Wait time for a counselor is 60 minutes. There are five counselors and each counselor see a student for an average of 30 minutes per day. How many new counselors are needed to shorten the wait time to 15 minutes?

*January 25, 2011*

**alg2**

Solve: 3x − 7 (sqrt x) + 2 = 0

*January 20, 2011*

**alg 2**

simplify (x^3/4)^3

*January 20, 2011*

**Social Studies**

for class, my teacher is making us do a booklet of key terms that we need to know. We have to draw pictures for each key term. I need some ideas on what to draw for Articles of Confederation and Land Ordinance of 1785. please help!

*January 19, 2011*

**Physics**

a) 4% b) 0.4% c) 0.07%

*January 17, 2011*

**HISTORY**

(This homework question was removed due to a copyright claim submitted by K12 Inc.) You do NOT have to write me my paragraph, but what I would like is for you to answer each question next to a bullet-point so I can write my paragraph. For example, answer each of these ...

*January 15, 2011*

**math**

2x-3y=12 x=4y+1 substitution, elemenation

*January 13, 2011*

**8th grade Math**

I need help finding heighth of a pyramid.

*January 13, 2011*

**MT**

Identify 2-3 business issues and provide an explanation of why technology cannot be used to aid or solve them.

*January 12, 2011*

**algebra**

thank you.

*January 11, 2011*

**algebra**

if a student has an average of 8 after 20 tests and then gets a 0 on his 21st test, what would his new average be?

*January 11, 2011*

**Chemistry**

If you start with ten grams of lithium hydroxide, how many grams of lithium bromide will be produced? Round to the nearest tenth. Don't forget the units.

*January 9, 2011*

**social studies**

This helped me a lot thank you so much!

*January 6, 2011*

**Math**

What is the units you measure for area please help fast

*January 5, 2011*

**English**

It's Relative Pronoun. David I is wrong because Demonstrative Pronouns are this, these, that and those.

*January 4, 2011*

**physics**

nina has a mass of 40 kg and bruno has a mass of 100 kg. they stand on a slippery surface and push off eachother. bruno has an acceleration of 1.0 m/s squared. what is nina's acceleration?

*December 22, 2010*

**PHYSICS**

santa drops a package from his sleigh while traveling at constant velocity. if there is no air resistance, with the package hit the ground in front of the sleigh, behind the sleigh, or directly below it? explain reasoning.

*December 22, 2010*

**PHYSICS**

does the sun exert a gravitational force on the earth? if so, why doesn't the earth fall into the sun?

*December 22, 2010*

**PHYSICS**

assume you have a mass of 100 kg on earth. on the moon, where the gravitation of the moon is 1/6 gravitation of the earth, what is your mass on the moon and what is your weight on the moon

*December 22, 2010*

**PHYSICS**

what are the components of a vector that has a magnitude of 1.5 m at the angle of 35 degrees with respect to the positive x axis

*December 22, 2010*

**PHYSICS**

Alex is doing tight circles with his car in an empty parking lot, all the while holding his speedometer reading to a steady 20 mph. Is Alex traveling at a constant velocity? Why or why not?

*December 22, 2010*

**11th grade**

A reflecting telescope contains a mirror shaped like a paraboloid of revolution. If the mirror is 4 inches across at its opening and is 3 inches deep, where will the collected light be concentrated?

*December 16, 2010*

**physics**

as an object is dropped from a high cliff, which of the following statistics can be made in regard to the objects potential energy?

*December 16, 2010*

**physics**

A ship approaches saturn at 10.4km/s and saturns speed is 9.6km/s (relative to the sun). Take the interaction as elastic collision. Saturns mass is greater than the space ship. Find the speed of the ship after it goes around Saturn.

*December 8, 2010*

**physics**

ladder of mass m and length l leans against a frictionless wall at an angle of 60 degrees. The coefficient of static friction between the ladder and ground is 0.45. A man whose mass is 4 times the ladder climbs up. How far up the ladder can he go before he slips?

*December 8, 2010*

**economics**

what is the history on credit cards?

*December 7, 2010*

**algebra 2**

A flagpole at a right angle to the horizontal is located on a slope that makes an angle of 12 degrees with the horizontal. The pole's shadow is 16 meters long and points directly up to the slope. The angle of elevation of the sun is 20 degrees. Draw the triangle. Write an ...

*December 7, 2010*

**Advanced Physics**

If wind blows at a speed of 30 m/s over the roof of your house, what is the pressure diference on your roof between the air inside and the air outside? What net force does this produce on a roof having an area of 175 m^2? 1.3 kg/m^3 is the density of air.

*December 5, 2010*

**Geometry**

Point H is the midpoint I'd line segment GJ Line segment GH is 7x-5 HJ is 4x+1 what is the value of X?

*December 5, 2010*

**Physics**

For part c, you use the help Ewater+Eiron=the answer from part a. So this would be the set up: (4186*5*delta T)+(448*1.2*delta T)=0.7 20930delta T + 537.6delta T = 0.7 21467.6delta T = 0.7 delta T= 3.26E-5

*December 3, 2010*

**organic chemistry**

How would i construct a graph of refractive index versus percent 1-bromooctane for KI and KCl reactions

*December 2, 2010*

**trig**

Find the sign of the expression if the terminal point determined by t is in the given quadrant. cos t X sec t in any given quadrant

*December 1, 2010*

**Math**

How to solve the simultaneous equations 3x + y = 17 and y = x + 1 ?

*December 1, 2010*

**College Algebra**

ln 2+6 ln x+4 ln (x^2=8) How would I rewrite the expression? I'm struggling in Math.

*November 30, 2010*

**physics**

Suppose you roll a bowling ball at 2.5 m/s across the roof of a flat building. It leaves the edge and strikes the ground 2.0 s later. How high is the roof? How far from the edge of the roof does the ball hit the ground?

*November 28, 2010*

**physics**

Two spheres A and B, where A has twice the mas of B, are projected at the same horizontal velocity off the edge of two different height shelves. Sphere A leaves from a height of 2.0 m. Sphere B leaves a shelf 1.0 m off the floor. If both spheres leave the edge if the table at ...

*November 28, 2010*

**psychology**

Surveys suggest that up to 4% of the U.S. population suffers from generalized anxiety disorder. How are anxiety disorders viewed by various psychological perspectives such as psychodynamic, biological, cognitive, and humanistic? With which perspective do you most agree? With ...

*November 23, 2010*

**Chemistry**

If the reaction Fe2N(s) + 3/2H2(g) -> 2Fe(s) +NH3(g) comes to equilibrium at a total pressure of 1 bar, analysis of the gas shows that at 700. and 800.K, PNH3/PH2=2.165 and 1.083 respectively, if only H2(g) was initially present in the gas phase and Fe2N(s) was in excess. a...

*November 23, 2010*

**ENGLISH**

Did I use the word sublimate correctly in the following sentence? "His stories served as a way to sublimate his anger for his childhood and improve the conditions for nineteenth-century adolescence."

*November 20, 2010*

**Chem**

A chemical reaction in a bomb calormeter evolves 4.66Kj of heat. If the heat capcity of the calorimeter is 1.38 Kj/C what is the temperature change?

*November 18, 2010*

**Calc**

A 100 inch piece of wire is divided into 2 pieces and each piece is bent into a square. How should this be done in order of minimize the sum of the areas of the 2 squares? a) express the sum of the areas of the squares in terms of the lengths of x and y of the 2 pieces b) what...

*November 16, 2010*

**Physics**

A long straight horizontal segment of wire with 0.060 m traverses a west magnetic field with 2.0 T. If a south current with 4.0 A flows through the wire, which one of the following statements concerning the effect of the magnetic force on the wire is true. a) The wire will be ...

*November 14, 2010*

**Geometry**

1) Find the lengths of the legs of two possible triangles whose areas would be as close as possible to one square inch without going under. 2) What if the triangle has to be an isoceles triangle? (area must be close to one square inch) (Give answers in ruler-friendly form in &...

*November 11, 2010*

**Math**

How do you solve 3/4x+1/2y=10 and -3/2x-y=4?

*November 10, 2010*

**algebra**

what is 4p+3q=36 9p+6q=78 ?

*November 10, 2010*

**math**

Three numbers in an arithmetic sequence sum to six. If you add 1 to the first number, 2 to the second number, and 5 to the third number, the result will be a geometric sequence. What are the original 3 numbers?

*November 8, 2010*

**Math**

i need help with this problem if u know the answer coment the answer below

*November 7, 2010*

**pre-algerbra**

I have been working on this problem for an hour and a half! I keep getting 1.33 but I know that's not right!! Jim drove the 120 miles to grandmothers house in 3 hours. He increased the speed by 10 miles per hour on the way home. How long did it take him to drive home?

*November 4, 2010*

**spanish 6th grade**

o ok thank you jen

*November 1, 2010*

**spanish 6th grade**

i think it is que comida es i am not sure????

*November 1, 2010*

**Accounting**

Jan. 1 Merchandise inventory $144,200 Jan. 1–Feb. 7 Purchases (net) 40,000 Jan. 1–Feb. 7 Sales (net) 70,000 Estimated gross profit rate 40% Estimated merchandise inventory destroyed:

*October 28, 2010*

**Pre Cal**

What is the inverse of g(x)= 1/2(x-1)^3-4

*October 25, 2010*

**chemistry 101**

how much energy is released when 10 g of steam at 100 degrees celsius is condensed and cooled to body temperature?

*October 24, 2010*

**Finance**

Find the least amount that could be deposited in a bank account today at 10% compounded quarterly to allow $650 withdrawals at the end of each quarter for 8 years?

*October 20, 2010*