# Posts by ALan

Total # Posts: 382

**Physics**

I will assume this is on Earth, with an acceleration due to gravity of 9.8 m/s/s. Force = mass * acceleration. A 50 kg mass therefore weighs 50 * 9.8 = 490 Newtons, which is the force required to lift the object. The energy required is force times distance, or 490 * 0.2 meters...

*March 5, 2017*

**science**

Steve's calculation is correct. It is worth noting that if you had an actual 1 gram block of Radium-226, its mass would NOT be reduced all the way to 0.9 grams after 241.7 years. Radium-226 decays by alpha emission to Radon-222, which goes quickly through a sequence of ...

*March 4, 2017*

**chemistry**

i literally have no idea how to do these and your explanations are not helping..... like i have no example and i need you to work one out and i can do the other but they are do soon and i have no clue what you are saying.

*February 19, 2017*

**chemistry **

A 8.408 gram sample of an organic compound containing C, H and O is analyzed by combustion analysis and 12.53 grams of CO2 and 3.849 grams of H2O are produced. In a separate experiment, the molar mass is found to be 118.1 g/mol. Determine the empirical formula and the ...

*February 19, 2017*

**chem**

for molecular i got 1 and 1 empirical i don't know what to do

*February 19, 2017*

**chem**

this completely confused me.... these are bonus problems we have not been taught for extra credit and i can't figure out the answers

*February 19, 2017*

**Chemistry**

What is the Net Ionic Equation for Nitric Acid and Potassium Carbonate?

*October 12, 2016*

**Chemistry**

What is the concentration in each of the following solutions? A) 240 mL of 0.200 M KNO3 is added to 160 mL of water. B) 2.25g of NaCl is dissolved in 250 ml of water.

*October 12, 2016*

**Chemistry**

The quantity of Cl- in a water supply is determined by titrating the sample with Ag+. What mass of chloride ion is present in a 10,0g sample of the water if 20.2 ml of 0.100 M Ag+ is required to react with all the chloride in the sample?

*October 12, 2016*

**Chemistry**

7. A student conducts an experiment on a different hydrate. The empty crucible is heated to a constant mass of 24.330. A sample of the unidentified hydrate is placed in the crucible, and the total mass is 31.571 g. The crucible and hydrate are heated to constant mass, which is...

*September 28, 2016*

**maths**

Gunpowder contains 75%nitre and10% sulphur.find the amount of gunpowder which carries 9 kg nitre . what amount of gunpowder would contain 2.5kg sulphur

*September 26, 2016*

**Maths**

-3x+2y=-6

*August 22, 2016*

**physics**

what is the maximum torque on a rectangular coil 5 cm x 12 cm and with 600 turns when carrying a current of 0.0700A in a uniform field with magnitude 0.300T?

*August 8, 2016*

**Chemistry**

5 grams of H2 reacts with 16 g of O2, which in excess? 2H2(g)+O2(g)=2H2O(g)

*May 21, 2016*

**math**

If the store purchases an item at a wholesale cost of $3.50 per item, and it is sold at a retail value of $5.00 per item. What is the gross profit percentage of the item?

*April 20, 2016*

**Geometry**

A wheel 2ft wide rolls a distance of .015 miles in .005 hours. What is the wheels speed in rpm's?

*March 31, 2016*

**Geometry**

The diagonals of rectangle ABCD intersect at point E. If AE=2x+5, and BD=5x+2, what is AC?

*February 24, 2016*

**Chemistry**

Nicotine is a basic substance and its dissociation constant is about 1.0 x 10-6. To prepare a solution water with 0.01 mol L-1, calculate the PH

*January 22, 2016*

**Chemistry**

An amount of 25ml of a 0.8 Molar solution of pure KNO3 and placed in a volumetric flask. Is added water until the thin volume reaches exactly 500ml. which the final concentration?

*January 21, 2016*

**Chemistry**

An aluminum sheet used for food preservation weighs about 0.05 g/cm-2 How many electrons are in a 1 cm2 of this sheet?

*January 21, 2016*

**algebra**

[Question] Can someone please argue with me against 'decreased' being a past-tense word? My interpretation: 3(x - 7) = x + 39. Please EXPLAIN why this is not the case even though it was worded this way. Thank you

*June 16, 2015*

**Math help Steve?**

Oh never mind! So the answer would be B?

*April 29, 2015*

**Math help Steve?**

1) Given that p(-3), p(-1), and p(5)=0, which expression could be p(x)? A)x^3-x^2-17x-15 B)x^3+x^2-17x+15 C)x^3-3x^2-13x+15 D)x^3-9x^2+23x-15 Hi Steve, I got what you said, but how would I solve this equation then?

*April 29, 2015*

**Math**

Hello again! I would appreciate help very much on this. Thank you! 1) For which values of x is y equal to 16 in the equation y=|3x+4|? A) -60 and 36 B) -36 and 60 C) -20/3 and 4 D) 20/3 and 4

*April 29, 2015*

**Math**

Oh ok, I understand that. Thank you so much!

*April 29, 2015*

**Math**

1. Which function represents an initial population that increases 22% per year where A represents the initial value and X represents time in years? A. Y=A(0.22)^x B. Y=A(0.68)^x C. Y=A(1.22)^x D. Y=A(1.68)^x I do not get how to solve this problem. Any help would be great. ...

*April 29, 2015*

**Math**

Thank you so much!

*April 29, 2015*

**Math**

Any help would mean so much to me. Thank you!

*April 29, 2015*

**Math**

1) Malene rented a compact car for 10 days and drove it 620 miles for a total cost of 412$. Patrick rented a compact car at the same rental car company for 6 days and drove it 850 miles. His total cost was 295. Which system of equations could be used to determind d, the charge...

*April 29, 2015*

**Math (check answers)**

1) Given that p(-3), p(-1), and p(5)=0, which expression could be p(x)? A)x^3-x^2-17x-15 B)x^3+x^2-17x+15 C)x^3-3x^2-13x+15** D)x^3-9x^2+23x-15 2) Coaches in a football conference had the option to vote for or against a rule change. The table below shows the results. 4 people ...

*April 29, 2015*

**Math**

1)If the roots of a quadratic equation are -2 and 3, the equation can be written as A) (x+2)(x+3) B) (x-2)(x+3)** C) (x+2)(x-2) D) (x-2)(x-3) Is the answer B? If someone could help me that would be great.

*April 29, 2015*

**Physics**

A constant retarding torque of 12 N*m stops a rolling 0.80 m diameter wheel in a distance of 15 m. How much work does the torque do?

*April 4, 2015*

**Physics**

Determine the acceleration of each object, including its direction. Determine the tensions in the two cords.

*February 11, 2015*

**Physics**

Three blocks are connected on the table as shown below. The coefficient of kinetic friction between the block of mass m2 and the table is 0.345. The objects have masses of m1 = 3.25 kg, m2 = 1.25 kg, and m3 = 2.50 kg, and the pulleys are frictionless. The Photo: w w w(dot)...

*February 11, 2015*

**algebra**

Mary wants to hang a mirror in her room. The mirror and frame must have an area of 7 square feet. The mirror is 2 feet wide and 3 feet long. Which quadratic equation can be used to determine the thickness of the frame, x? (4 points)

*February 7, 2015*

**math**

Can anyone please provide a detailed answer for this question

*January 19, 2015*

**Physics**

The resonator of a string instrument is commonly an oddly shaped box or a wide thin board. The resonator is not sharply tuned; it responds to broad bands of frequencies and radiates sound at those frequencies from its entire surface area. The response of the body or soundboard...

*December 20, 2014*

**History**

Was the only change in science in quantum physics and relativity? I know it changed the way people thought about the predictability of human nature during the enlightenment and the 1st scientific revolution, but how did this contribute to the age of anxiety? I don't ...

*December 18, 2014*

**History**

I have to write a 150-200 word essay on it

*December 18, 2014*

**History**

What were the major changes in sciences view of the nature of the universe and humanity's place in it between 1850 and 1914? How did these developments contribute to the age of anxiety? How are these changes reflected in philosophy, psychoanalysis, and artistic style ...

*December 18, 2014*

**AP Calc**

Wait don't you plus x=14 back in to y=(84-4x)? Cause y then equals 20 in

*December 1, 2014*

**AP Calc**

The US Post Office has a limit on the size of packages it will accept for mailing. The length plus the girth must be 84 inches or less. Find the dimensions of the rectangular package with a square end, which will maximize the volume of the package.

*December 1, 2014*

**MATH**

Mimi's Market sold 24 heads of lettuce one morning. That afternoon 2/7 of the remaining heads of lettuce were sold. The number of heads left was now 1/2 of the number the market had at the beginning of the day. How many heads of lettuce were there at the beginning of the day?

*November 17, 2014*

**math/set theory**

120 quilts were entered into a quilt show. (Traditionally, all quilts were hand stitched but now many are stitched on machines. Appliques are additional pieces of cloth that are sewn on top of the quilt.) In this show, 86 were machine stitched. 44 had appliques applied. 24 ...

*November 13, 2014*

**Social Studies**

What are some lifestyles for the following countries: -Kazakhstan -Kyrgyzstan -Latvia -Liechtenstein

*October 9, 2014*

**Physics**

A ball rolling with initial velocity of 40m/s(W) undergoes an acceleration of 5.0m/s^2(N) for a period of 6.0seconds. (A) what is the final velocity of the ball? (B) what is the displacement of the ball in the 6.0 sec

*October 7, 2014*

**Physics**

A ball rolling with initial velocity of 40m/s(W) undergoes an acceleration of 5.0m/s^2(N) for a period of 6.0seconds. (A) what is the final velocity of the ball? (B) what is the displacement of the ball in the 6.0 sec

*October 7, 2014*

**Maths**

Mathew is attending a very loud concert by the discarded. To avoid permanent ear damage he decides to move farther from the stage. Sound intensity is given by the formula I=k/d*d where k is the constant and d is the distance in metres from the listener to the source of the ...

*October 1, 2014*

**math**

Fred has 15 cows John has twice as many cows as Fred had when Fred had as many cows as John has now how many cows has John?

*September 21, 2014*

**Organic Chemistry**

What ketone or aldehyde would be reduced to produce each alcohol, respectively: a. 3,3-Dimethyl butan-2-ol b. 3-Methyl butan-1-ol c. Benzyl alcohol

*May 24, 2014*

**Biology - Help!!**

2 and 5 are wrong for anyone who may use this to answer their test

*May 20, 2014*

**ch**

A 0.160-g sample of unknown metal (X) reacts with hydrochloric acid to produce 66.5 mL? Help please

*April 23, 2014*

**Math**

Evaluate the expression for the given value. x = 3; y = -5; z = -2 x(yz)^2 - 3(xyz)^0 + 2x^2yz^2 = 3(-5 * -2)^2 - 3(3 * -5 * -2)^0 + 2(3)^2(-5 * -2)^2 = 3 * 100 - 3 * 30 + 2 * 9 300 - 90 + 18 = 228

*November 25, 2013*

**Please check this answer if this is correct.**

-2(-2)^2 * 3 - 3(-2)(3)^2 * -1 - (-2)(-1) -2 * -4 * 3 - 3(-2) * 9 * -1 (-2)(-1) -2 * -4 * 3 - 6 * 9 * -1 * 2 24 - 108 = -84

*November 24, 2013*

**Math**

Evaluate the expression for the given value. x = -2; y = 3; z = -1 -2x^2y - 3xy^2z - xz =

*November 24, 2013*

**Chemistry**

In a double-stranded DNA molecule, the percentage of Guanine can never be more than ___%. Why?

*November 22, 2013*

**Chemistry**

Which of the following statements must be True? Check all that apply. The number of Adenines in single-stranded DNA equals the number of Thymines. The number of Guanines in single-stranded DNA equals the number of Adenines. The number of Thymines in double-stranded DNA equals ...

*November 21, 2013*

**Math**

Solve the following: -6x + 3 <= 25

*November 19, 2013*

**Math**

Solve the following. 2(x + 1) - 4 <= 1/4(12x - 24)

*November 19, 2013*

**Math**

Evaluate when x = 2, y = -5, z = 3. x^2 - y = 3 3z - 4(y + 1) - y^2 = 0 x - yz = -13

*November 19, 2013*

**Math**

Simplify or solve as appropriate. Enter ns if there's no solution or all if the solution is all real numbers. 2 - 3(x + 5)) = 10 X = -7.6 7z + 6 - 2(z + 3) 5 * z 1/2x - 5 = 3/4x + 7 X = -48

*November 19, 2013*

**Math**

Using the linear equation y = -3x + 5, complete the table of values (T-Chart) and choose the correct graph. X = -2 Y = _ X = -1 Y = _ X = 0 Y = _ X = 1 Y = _ X = 2 Y = _

*November 19, 2013*

**Math**

Using the linear equation y = 5, answer each of the following. Choose all points that would be on this line. (0,5), (5,5), (2,5), (5,2), (-3,5), or (5,-3)

*November 18, 2013*

**Math**

Find the x-intercept and the y-intercept of the linear equation 3x + 4y = 12. Write each intercept as an ordered pair.

*November 18, 2013*

**Please check if these math questions are correct**

8 = p - 5 Answer: p = 13 21 + y = 35 Answer: y = 14 6x = 54 Answer: x = 9

*November 17, 2013*

**Math**

Solve -4x is less then equal to -16. I got x is less then equal to 4. Is this correct I'm kind of confused with this question.

*November 17, 2013*

**Math**

Solve for X. X/8 = -4/9

*November 17, 2013*

**Math**

Evaluate the following expressions when x = -2, y = 6, and z = -4 y^2 + 3z 5y - 3(x^2 + 1) + z

*November 16, 2013*

**Math**

When driving to the beach, you drive 240 miles on 9 gallons of gas. When you arrive at the beach you fill up your gas tank. While there you drive 130 miles and use 5.8 gallons of gas. Round answers to 2 decimal places. What was your gas mileage driving to the beach? What was ...

*November 16, 2013*

**Math**

Choose True or False for each of the following. 87% is equivalent to 0.87 True or False 1.29 is equivalent to 129% True or False 0.5% is equivalent t0 0.05 True or False 5.6 is equivalent to 56% True or False

*November 15, 2013*

**Math**

Convert each of the following. Round your answer to two decimal places if necessary. 0.68 miles = 43084.80 inches 10259 feet = 3419 yards

*November 15, 2013*

**Math**

If a boat travels at 5 miles per hour, how many feet per second does it travel? Round your answer to two decimal places if necessary. 26400 feet per second

*November 15, 2013*

**Math**

Three friends go to their favorite seafood restaurant for dinner. They decide to order a crab cake appetizer. When it arrives there are only 2 crab cakes. What fraction of a crab cake will each friend get to eat? 3/2 Write the fraction as a decimal rounded to 2 decimal places...

*November 14, 2013*

**Math**

Your favorite chocolate chip cookie recipe makes 4 dozen cookies. Among the other ingredients, the recipe calls for > 1 cup of butter > 2 tsp vanilla extract > 3 cups of flour > 1/2 tsp salt You are asked to make 6 dozen cookies for a party. How much butter, ...

*November 14, 2013*

**Math**

Perform the indicated operation and simplify. 1. 1/4 + 1/3 = 2/3 2. 4/7 - 5/6 = 1/6 3. 3/5 * -4/7 = -12/35 4. 10/11 divided by 2/3 = 15/11

*November 14, 2013*

**Math**

Is 10.512 * 10^3 written in proper scientific notation? If not rewrite the number in proper scientific notation.

*November 14, 2013*

**Math**

You have a table in your living room with a round top that has a diameter of 2 1/2 feet. You would like to put a piece of glass over the top of the table to protect the surface. What is the area of the table top? (Use 3.14 for the value of pi). Write your answer as a mixed ...

*November 14, 2013*

**Math**

You pull into a gas station where the sign says the gas costs $3.679. To fill up your tank you need 20 1/2 gallons of gas. You plan to use your credit card to pay. Rounded to the nearest cent, what will the charge be on your credit card? $75

*November 14, 2013*

**Math**

Perform the indicated operation. Write your answer as a simplified fraction. 1. 1/3 + 0.25 = 7/12 2. 0.3125 - 1/4 = 1/16 3. -7/10 + 0.2 = -9/10

*November 13, 2013*

**Math**

Convert the following decimals to a simplified mixed number. 1. 0.33 = 1/3 2. 1.875 = 1 7/8

*November 13, 2013*

**Math**

You and your friend ordered a 12 inch pizza to split for lunch. How many square inches of pizza do you each get to eat? Round answer to 2 decimal places. 37.68 square inches

*November 13, 2013*

**Math**

You live 35 1/3 miles from your grandmother's house. You're workplace is 7 2/5 miles from your grandmother's house. If you drive by your grandmother's home on the way to work one morning, what is the total number of miles you drove that morning? Write your ...

*November 13, 2013*

**Math**

Multiply each of the following. Write your answer as a simplified fraction. 1. 4/7 * 5 = 20/7 2. 15/28 * 7/9 = 105/252 3. -3 1/5 * 7/8 = -56/20

*November 13, 2013*

**Math**

Add each of the following. Write answer as a simplified improper fraction. 1. 3/25 + 8/35 = 61/175 2. 5 1/4 + 3 5/12 = 26/3 3. -4 1/2 + 2 2/3 = -19/6

*November 13, 2013*

**Math**

-3 7/16 = -41/16 = -2.56 25/13 = 1.92

*November 13, 2013*

**Math**

Convert the following fractions to decimals. Round to 2 decimal places if necessary. 1. 1/4 2. -3 7/16 3. 25/13

*November 13, 2013*

**Math**

Simplify each of the following. 1. 42/48 2. -15/35 3. 119/210

*November 12, 2013*

**Math**

Write as an improper fraction. 1. 7 3/5 2. -12 1/2 3. 41 4/6

*November 12, 2013*

**Math**

Write as a mixed number. 1. 13/11 2. -33/6

*November 12, 2013*

**Math**

My son doesn't how to do 15+37

*October 23, 2013*

**Algebra**

I think it 32

*October 21, 2013*

**6th grade social studies**

What series of events led to the end of Egypts power in the Nile River Valley?

*September 26, 2013*

**History**

How did having few industries affect southerners. Can someone please help me with this question

*September 2, 2013*

**chemistry**

How many moles of H2O are needed to react with 15.0g of CaO forming Ca (OH)2? CaO + H2O --> Ca (OH)2

*July 15, 2013*

**Math (Please help ASAP?)**

I have this weird question that has to do with linear equations (I think), and this is what it says. Let f(x) = 4x - 5 A. Find f(3) B. Find x when f(x) = -21 Can somebody help me understand this??

*May 31, 2013*

**Math**

The parabola, B, represents a shuriken's maximum throwing distance, which was 60 meters of the enemy ninja, A, from a height of 7 meters. Figure out the trait of the enemy ninja that can be observed from the ellipse formed by the shuriken, and figure out the maximum ...

*May 24, 2013*

**Chemistry**

N-type silicon (Si) has been produced by doping with phosphorus (P). The charge-carrier population based on electrical conductivity measurments is determined to be 3.091*10^17 carriers/cm3 at room temperature. 1. Calculate the doping level of P (how much P has been added to ...

*April 25, 2013*

**Chemistry**

A glass of composition 85% SiO2 - 15% K2O is to be surface strengthened by ion exchange. To this end, two identical specimens approximately the size and shape of credit cards are soaked for the same amount of time at 850∘C. Sample A is soaked in NaCl and sample B is ...

*April 13, 2013*

**Chemistry**

Consider the heterogeneous equilibrium process shown below. C(s) + CO2(g) 2 CO(g) At 700.°C, the total pressure of the system is found to be 3.87 atm. If the equilibrium constant KP is 1.52, calculate the equilibrium partial pressures of CO2 and CO.

*February 23, 2013*