Friday

February 27, 2015

February 27, 2015

Total # Posts: 779

**Chemistry**

How much heat is needed to change 3kg of copper from a solid to a liquid? Heat of fusion = 205,000 J/kg
*February 23, 2015*

**Biology**

You have a stock solution with following components: glucose: 44 g/L NaCl: 191 g/L Tris Buffer: 275 g/L You mix 71 mL of the solution with water and bring the resulting solution to a final volume of 750 mL. What is the final concentration of glucose in g/L?
*February 10, 2015*

**Biology**

You prepare a solution by dissolving 319 g of glucose and 114 g of NaCl in water and bring the final volume up to 1,088 mL. What is the final concentration of glucose in g/L?
*February 10, 2015*

**Calculus**

At 2:00pm a car's speedometer reads 60mph, and at 2:10pm it reads 65mph. Use the Mean Value Theorem to find an acceleration the car must achieve. Answer( in mi/h2):
*February 8, 2015*

**Math**

If a and b are positive numbers, find the maximum value of f(x)=x^a(1−x)^b, 0≤x≤1 Your answer may depend on a and b.
*February 8, 2015*

**math**

The demand function for the Sicard wristwatch is given by the following function where d(x) (measured in units of a thousand) is the quantity demanded per week and x is the unit price in dollars. d(x) = 50 0.01x2 + 1 (0 ≤ x ≤ 20) (a) Find d'(x). d'(x) = (b...
*February 6, 2015*

**Math**

Thanks
*February 4, 2015*

**Math**

a-7 is divided by 10 = a-2 divided by 8
*February 4, 2015*

**Math**

a-7= a-2 ---- ---- 10 8 a=????
*February 4, 2015*

**College Algebra**

Translate the following statement. Into an alegebraic expression use x for your variable the sum of the cube if a number and seven times number
*February 3, 2015*

**Math**

An airplane in Australia is flying at a constant altitude of 2 miles and a constant speed of 600 miles per hour on a straight course that will take it directly over a kangaroo on the ground. How fast is the angle of elevation of the kangaroo's line of sight increasing when...
*February 1, 2015*

**Math**

preparing to make 4 white tents you discover each one will require 2.5 square yards of silk. If each square yard of silk costs $4.00, how much will it cost to make all the tents? Do I multiple 2.5 times $4.00 to get the answer?
*January 22, 2015*

**math**

Lee wants to cut this piece of canvas into two rectangles that are 3×2 and 3×5. He wants the sum of the areas of the two small rectangles to be the same as the area of the large rectangle. Can he do this? Explain
*January 20, 2015*

**algebra**

Ten years from now Tim will be twice as old as Jane was when mary was nine times as old as tim. Eight years ago, Mary was half as old as Jane will be when jane is one year older than Tim will be at the time when Mary will be five times as old as Tim will be two years from now...
*January 17, 2015*

**math**

It's been several years since I have had to do math and I am posed with this ? and don't recall how to find the answers. There is a fixed overhead of $1 per bolt. They make a run of 10,000 bolts at a total marginal cost of $70k. They sell them all, and lose $20k. What ...
*December 26, 2014*

**physics**

A 1000 kilogram car rolling on a horizontal surface has speed v= 45 kilometer per hour when it strikes a horizontal coil spring and is brought to rest in a distance of 2.2 meters. What is the spring stiffness constant of the spring?
*November 5, 2014*

**algebra**

Christ is building a rectangular where the front and back are 5' each. The perimeter of the dog house needs to be 28'. How long will each side of the dog house be?
*October 30, 2014*

**chemistry**

Gaseous methane CH4 will react with gaseous oxygen O2 to produce gaseous carbon dioxide CO2 and gaseous water H2O . Suppose 0.481 g of methane is mixed with 2.9 g of oxygen. Calculate the maximum mass of carbon dioxide that could be produced by the chemical reaction. Be sure ...
*October 3, 2014*

**Chemistry**

NEVER MIND
*October 1, 2014*

**Chemistry**

A solution contains Cr3+ ion and Mg2+ ion. The addition of 1.00 L of 1.55M NaF solution is required to cause the complete precipitation of these ions as CrF3(s) and MgF2(s). The total mass of the precipitate is 49.9g .Find the mass of Cr3+ in the original solution.
*October 1, 2014*

**physics question solved**

What is the rate of deceleration of a 1400-kg SUV that is going 75.0 km/h and then slows to 25.0 km/h in 8.20 s? Figured it out, Don't worry about the mass, just solve for Deceleration. which is deltavelocity/delta time >>Subtract First(75 - 25) = 50 km/hr*(1hr/3600 ...
*October 1, 2014*

**Physics**

Figured it out, Don't worry about the mass, just solve for Deceleration. which is deltavelocity/delta time >>Subtract First(75 - 25) = 50 km/hr*(1hr/3600 sec) = 50/3600 = 0.01389 km/s. <<Dont Forget the conversion to sec >>>Then delta velocity/ delta ...
*October 1, 2014*

**Physics**

What is the rate of deceleration of a 1400-kg SUV that is going 75.0 km/h and then slows to 25.0 km/h in 8.20 s?
*October 1, 2014*

**Medical Billing & Coding**

A physician performed an aspiration via thoracentesis on a patient in observation status in the hosptial. The patient has advanced lung cancer with malignant pleural effusion. Later the same day, due to continued accumulation of fluid, the patient was returned to the procedure...
*July 28, 2014*

**MAT 116**

If a > 0 and b < 0, then which of the following must be true
*May 4, 2014*

**math**

an unbiased coin is tossed six times. find the probability of the given event. the coin lands heads more than once.
*April 23, 2014*

**math**

a pair of dice is rolled. what is the probabilty of each of the following? a. the sum of the numbers shown uppermost is less than 5. b. at least one six is cast.
*April 15, 2014*

**american national goverment**

1. Locke’s use of the term “property” (Points : 1) serves to stress the absolute sanctity of property. serves as a defense against the arbitrary exercise of power and authority. dramatizes his commitment to natural law. means that a sovereign who seizes property...
*April 13, 2014*

**Chemistry**

Why do I subtract .9375 from H^+ instead of adding .9375 and then subtracting .9375 from NH4^+ instead of adding?
*April 10, 2014*

**Chemistry**

Okay thank you so much!
*April 10, 2014*

**Chemistry**

A buffer solution is prepared by mixing 50.0 mL of 0.300 M NH3 with 50 mL of 0.300 NH4Cl. The pKb of NH3 is 4.74. NH3 + H2O-> NH4+ +OH- 7.50 mL of 0.125 M HCl is added to the 100 mL of the buffer solution. Calculate the concentration of NH3 and NH4Cl for the buffer solution...
*April 10, 2014*

**Calculus**

Using f(x), determine a formula for the Riemann Sum S_n obtained by dividing the interval [0, 4] into n equal sub-intervals and using the right-hand endpoint for each c_k. f(x)= 5x+2 Now compute the limit as n goes to infinity S_n to compute the area under the curve over [0,4].
*April 7, 2014*

**chemistry**

a piece of metallic iron (10 moles) was dissolved in concentrated hydrochloric acid. the reaction formed iron (II) chloride and hydrogen gas. how many moles of iron (II) chloride were formed?
*March 26, 2014*

**Math**

Suppose that Ramos contributes $6000/year into a traditional IRA earning interest at the rate of 2%/year compounded annually, every year after 35 until his retirement age at age 65. At the same time, his wife Vanessa deposits $4900/year into a Roth IRA earning interest at the ...
*March 22, 2014*

**math**

Base is found by ________ the portion by the rate
*March 1, 2014*

**physics**

Two insulated wires, each 2.70 m long, are taped together to form a two-wire unit that is 2.70 m long. One wire carries a current of 7.00 A; the other carries a smaller current I in the opposite direction. The two wire unit is placed at an angle of 77.0° relative to a ...
*February 26, 2014*

**physics**

A proton, traveling with a velocity of 4.9 106 m/s due east, experiences a magnetic force that has a maximum magnitude of 7.4 10-14 N and a direction of due south. What are the magnitude and direction of the magnetic field causing the force?
*February 26, 2014*

**physics**

The drawing shows a parallel plate capacitor that is moving with a speed of 30 m/s through a 3.1 T magnetic field. The velocity vector v is perpendicular to the magnetic field. The electric field within the capacitor has a value of 170 N/C, and each plate has an area of 7.5 10...
*February 26, 2014*

**college math **

CalJuice Company has decided to introduce three fruit juices made from blending two or more concentrates. These juices will be packaged in 2-qt (64-oz) cartons. One carton of pineapple-orange juice requires 8 oz each of pineapple and orange juice concentrates. One carton of ...
*February 23, 2014*

**college math **

Acrosonic manufactures a model G loudspeaker system in Plants I and II. The output at Plant I is at most 800/month, and the output at Plant II is at most 600/month. Model G loudspeaker systems are also shipped to the three warehouses—A, B, and C—whose minimum monthly...
*February 23, 2014*

**college math HELP!!!!!**

Acrosonic manufactures a model G loudspeaker system in Plants I and II. The output at Plant I is at most 800/month, and the output at Plant II is at most 600/month. Model G loudspeaker systems are also shipped to the three warehouses—A, B, and C—whose minimum monthly...
*February 22, 2014*

**college math HELP!!!!!**

CalJuice Company has decided to introduce three fruit juices made from blending two or more concentrates. These juices will be packaged in 2-qt (64-oz) cartons. One carton of pineapple-orange juice requires 8 oz each of pineapple and orange juice concentrates. One carton of ...
*February 22, 2014*

**college math HELP!!!!!**

Sharon has a total of $190,000 to invest in three types of mutual funds: growth, balanced, and income funds. Growth funds have a rate of return of 12%/year, balanced funds have a rate of return of 10%/year, and income funds have a return of 6%/year. The growth, balanced, and ...
*February 22, 2014*

**College math HELP!!!!!**

nevermind, i figured it out. thank you!
*February 22, 2014*

**College math HELP!!!!!**

how did you get 0.6?
*February 22, 2014*

**College math HELP!!!!!**

A financier plans to invest up to $450,000 in two projects. Project A yields a return of 10% on the investment, whereas Project B yields a return of 15% on the investment. Because the investment in Project B is riskier than the investment in Project A, the financier has ...
*February 22, 2014*

**MATH HELP!!!!!!!!**

i need the 3 numbers for the answer, how do i find that?
*February 9, 2014*

**MATH HELP!!!!!!!!**

| 3 2 7 | x1 | | 46 | | -2 1 4 | x2 | = | 12 | | 6 -5 8 | x3 | | 60 | (b). Solve the system using the inverse of the coefficient matrix. (x1, x2, x3) = (________)
*February 9, 2014*

**physics**

An electric heater used to boil small amounts of water consists of a 25-Ω coil that is immersed directly in the water. It operates from a 60-V socket. How much time is required for this heater to raise the temperature of 0.50 kg of water from 29° C to the normal ...
*January 27, 2014*

**physics**

A tungsten wire has a radius of 0.077 mm and is heated from 20.0 to 1205 °C. The temperature coefficient of resistivity is α = 4.5 10-3 (C°)−1. When 110 V is applied across the ends of the hot wire, a current of 1.3 A is produced. How long is the wire? ...
*January 27, 2014*

**Business Math**

Convert the following mixed number to an improper fraction: 12 3/4
*January 25, 2014*

**college math HELP!!!!!**

i need to find equilibrium price using these two equations: P= -(1/25)x+190 P= (1/75)x+70 the equilibrium quantity is: 2250 units the equilibrium price is: ______?
*January 20, 2014*

**math HELP!!**

The quantity demanded x each month of Russo Espresso Makers is 250 when the unit price p is $180; the quantity demanded each month is 1000 when the unit price is $150. The suppliers will market 750 espresso makers if the unit price is $80. At a unit price of $90, they are ...
*January 20, 2014*

**college math HELP!!!!!**

The quantity demanded x each month of Russo Espresso Makers is 250 when the unit price p is $180; the quantity demanded each month is 1000 when the unit price is $150. The suppliers will market 750 espresso makers if the unit price is $80. At a unit price of $90, they are ...
*January 19, 2014*

**college finite math**

The quantity demanded x each month of Russo Espresso Makers is 250 when the unit price p is $180; the quantity demanded each month is 1000 when the unit price is $150. The suppliers will market 750 espresso makers if the unit price is $80. At a unit price of $90, they are ...
*January 19, 2014*

**college finite math**

A product may be made using Machine I or Machine II. The manufacturer estimates that the monthly fixed costs of using Machine I are $17,000, whereas the monthly fixed costs of using Machine II are $14,000. The variable costs of manufacturing 1 unit of the product using Machine...
*January 19, 2014*

**college finite math**

A division of a company produces "Personal Income Tax" diaries. Each diary sells for $6. The monthly fixed costs incurred by the division are $30,000, and the variable cost of producing each diary is $1. (a) Find the break-even point for the division. (x, y) = (6000...
*January 19, 2014*

**college finite math**

Cowling's Rule is a method for calculating pediatric drug dosages. If a denotes the adult dosage (in milligrams) and if t is the child's age (in years), then the child's dosage is given by D(t) = (t + 1/24)a (a) Show that D is a linear function of t. Hint: Think of...
*January 19, 2014*

**college finite math**

Cowling's Rule is a method for calculating pediatric drug dosages. If a denotes the adult dosage (in milligrams) and if t is the child's age (in years), then the child's dosage is given by D(t) = (t + 1/24)a (a) Show that D is a linear function of t. Hint: Think of...
*January 19, 2014*

**college finite math**

For wages less than the maximum taxable wage base, Social Security contributions (including those for Medicare) by employees are 7.65% of the employee's wages.† (a) Find an equation that expresses the relationship between the wages earned (x) and the Social Security ...
*January 19, 2014*

**Physics**

In a vacuum, two particles have charges of q1 and q2, where q1 = +3.7 µC. They are separated by a distance of 0.22 m, and particle 1 experiences an attractive force of 3.5 N. What is q2 (magnitude and sign)?
*January 8, 2014*

**english **

What part of speech is coursework?
*January 1, 2014*

**college Algebra**

Write the system as a matrix and solve it by Gauss-Jordan elimination. (If the system is inconsistent, enter INCONSISTENT. If the system has infinitely many solutions, show a general solution in terms of x, y, or z.) x + 2y − z = 5 2x − y + z = 2 3x − 4y + 3z...
*December 15, 2013*

**college Algebra**

Use matrix methods to solve the problem. To use space effectively, librarians like to fill shelves completely. One 105-inch shelf can hold 3 dictionaries, 5 atlases, and 1 thesaurus; or 6 dictionaries and 2 thesauruses; or 2 dictionaries, 4 atlases, and 3 thesauruses. How wide...
*December 13, 2013*

**college Algebra**

thank you
*December 13, 2013*

**college Algebra**

Use matrix methods to solve the problem. 120,000 gallons of fuel are to be divided between two airlines. Triple A Airways requires three times as much as Unity Air. How much fuel should be allocated to Triple A? ______ gal
*December 13, 2013*

**college Algebra**

i have no clue why its not working... i tried: 0,0,0 9,9,9 INCONSISTENT
*December 13, 2013*

**college Algebra**

its saying its wrong? :/
*December 13, 2013*

**college Algebra**

i think you used the wrong one for the third line... x+z=18 y+z=18 x-z=0
*December 13, 2013*

**college Algebra**

the answer didnt work...
*December 13, 2013*

**college Algebra**

Solve the system, if possible. (If the system is inconsistent, enter INCONSISTENT. If the system is dependent, enter a general solution in terms of x, y, or z.) x + y = 18 y + z = 18 x − z = 0
*December 13, 2013*

**college Algebra**

Solve the system, if possible. (If the system is inconsistent, enter INCONSISTENT. If the system is dependent, enter a general solution in terms of x, y, or z.) x + y + z = 7 2x + y + z = 14 x + 2y + 3z = 2
*December 13, 2013*

**College Algebra**

thank you, big help
*December 12, 2013*

**College Algebra**

Use a system of equations to solve the problem. A rectangular picture frame has a perimeter of 2,200 centimeters and a width that is 300 centimeters less than its length. Find the area of the picture. _____ cm2
*December 12, 2013*

**Physics**

A 0.125 kg meter stick is rotating (as shown to the right) in a horizontal plane about an axis through its center at 3.45 rad/s. a) Find the rotational inertia of this stick. At one of its ends, find its b) speed and c) centripetal acceleration. If this stick comes to rest in ...
*December 2, 2013*

**Algebra**

Thanks, Steve. I was having a mental block on this one and knew it was easy! I appreciate your help.
*November 26, 2013*

**Algebra**

This homework question was removed due to a copyright claim submitted by the National Network of Digital Schools Management Foundation (NNDS).
*November 26, 2013*

**algebra 1**

Each of the values in your table shows an x value and a corresponding y value. So, your ordered pairs are: {(4,3), (2,5), (2,2), (3,5), (1,1)} Graph them. The domain is {1,2,3,4} or the x values in numerical order and not listed more than once. The range is {1,2,3,5} or the y ...
*November 26, 2013*

**algebra**

that's exactly what I got but it keeps saying it is wrong.
*November 21, 2013*

**algebra**

find all roots of the polynomial equation. x^5+3x^4-2x^3-14x^2-15x-5=0.
*November 21, 2013*

**algebra**

thank you soooo much!!!
*November 21, 2013*

**algebra**

a hot-air balloon is tethered to the ground and only moves up and down. You and a friend take a ride on the balloon for approximately 25 minutes. On this particular ride the velocity of the balloon, v(t) in feet per minute, as a function of time, t in minutes, is represented ...
*November 21, 2013*

**algebra**

Help me factor x^2 -2x - 4 = 0 and 3x^2 + x + 3 = 0.
*November 18, 2013*

**college algebra**

A partial solution set is given for the polynomial equation. Find the complete solution set. (Enter your answers as a comma-separated list.) x^3 + 3x^2 − 14x − 20 = 0; {−5}
*November 18, 2013*

**college algebra**

Use long division to perform the division. (Express your answer as quotient + remainder/divisor.) (x^4 + 7x^3 − 2x^2 + x − 1) / (x − 1)
*November 18, 2013*

**college algebra**

Solve the exponential equation using logarithms. Give the answer in decimal form, rounding to four decimal places. (Enter your answers as a comma-separated list.) 4^(x − 3) = 3^(2x) x = _____
*November 18, 2013*

**college algebra**

Use a calculator to help solve the problem. An isotope of lead, 201Pb, has a half-life of 8.4 hours. How many hours ago was there 40% more of the substance? (Round your answer to one decimal place.) ____hr
*November 18, 2013*

**college algebra**

not sure how to find the t, tried using the log approach but can't get the right answer.
*November 17, 2013*

**college algebra**

An isotope of lead, 201Pb, has a half-life of 8.4 hours. How many hours ago was there 40% more of the substance? (Round your answer to one decimal place.) ____hr
*November 17, 2013*

**college algebra**

no it looks more like this: 4^(x-3)=3^2x
*November 17, 2013*

**college algebra**

Solve the exponential equation using logarithms. Give the answer in decimal form, rounding to four decimal places. (Enter your answers as a comma-separated list.) 4x − 3 = 32x x = _____
*November 17, 2013*

**college algebra**

In 4 years, 30% of a radioactive element decays. Find its half-life. (Round your answer to one decimal place.) _____ yr
*November 17, 2013*

**college algebra**

thank you
*November 4, 2013*

**college algebra**

Use a calculator to find y to four decimal places, if possible. (If an answer is undefined, enter UNDEFINED.) ln y = log 9
*November 4, 2013*

**college algebra**

Use a calculator to find y to four decimal places, if possible. (If an answer is undefined, enter UNDEFINED.) ln y = −0.35
*November 4, 2013*

**college Algebra**

Use a calculator to find y to four decimal places, if possible. (If an answer is undefined, enter UNDEFINED.) ln y = −0.35
*November 4, 2013*

**college Algebra**

Use a calculator to find y to four decimal places, if possible. (If an answer is undefined, enter UNDEFINED.) ln y = log 9
*November 4, 2013*

**college Algebra**

Thank you, big help!
*November 4, 2013*

**college Algebra**

Use a calculator to help solve the problem. The life expectancy of white females can be estimated by using the function = 78.5(1.001)x, where x is the current age. Find the life expectancy of a white female who is currently 50 years old. Give the answer to the nearest tenth. L...
*November 4, 2013*

**college algebra**

i did that and it is not working. i get 0.0348
*November 4, 2013*

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