Sunday

April 20, 2014

April 20, 2014

Total # Posts: 678

**Math**

Brian's boat has a top speed of 9 miles per hour in still water. While traveling on a river at top speed, he went 10 miles upstream in the same amount of time he went 20 miles downstream. Find the rate of the river current.

**Calculus**

At what interval is e^(-5x^2) concave up? I know the second derivative is 100x^2*e^-5x^2-10*e^-5x^2 but I just can not figure this one out. Thank you for your help!

**philosophy (john dewey)**

The expected outcome or pattern of Developed Standards of "Rules of Conduct", "Moral Training" and "School Organizations" served to meet the national demands. What is the problem with this being upheld in our educational system?

**math**

Mr Tan has some amount of money. If he distributes equally to 2 persons, he left with $1. If he distributes equally to 3 persons, he left with $2. If he distributes equally to 4 persons, he left with $3. If he distributes equally to 5 persons, he left with $4. If he distribute...

**statistics, math, college**

if np >5 and nq>5 estimate P (fewer than 4) with n=13 p=0.4 by using normal distribution as an approximate to the binomial distribution if np <5 or nq< then state that the normal approximation is not suitable

**statistics, math, college**

assume that adults have I.Q scores that are normally distributed with a mean of 100 and a standard deviation 15. find p2 which is the IQ score seperating bottom 2% from the top 98%

** statistics**

The assets(in billions of dollars) of the four wealthiest people in a particular country are 43,25,21,15 assume that samples of size n=2 are randomly selected

**geometry**

v-2/81pir2h

**chemistry**

What will be the average density for a sample of metal with a mass of 12.6 g and volume calculations of 7.8 mL and 8.3 cm3 ? Omit units in the answer and report answer to one decimal place.

**chemistry**

What will be the average density for a sample of metal with a mass of 12.6 g and volume calculations of 7.8 mL and 8.3 cm3 ? Omit units in the answer and report answer to one decimal place.

**Math**

A 6 ft man stands by a 30 ft tower and casts a 10 ft shadow. How long is the shadow cast by the tower and what time is it?

**Math**

A 6 ft man stands by a 30 ft tower and casts a 10 ft shadow. How long is the shadow cast by the tower and what time is it?

**math**

How many nickels and dimes does it take to make $1.95

**Half-life**

After two hours, 1/16 of the initial amount of a radioactive isotope remains undecayed. What is the half-life of the isotope?

**algebra**

thank you I'll check back with my teacher.

**algebra**

Sorry about the signs. The answer was suppose to be 2 seconds. That's what I'm not understanding. I'm coming out with what you have- I moved over the 2 and that left the t^2 = 39/2 but that doesn't come out to be two seconds which is suppose to be the answer

**algebra**

I'm stuck with this problem. h = -16t^2 + 312 the "t" is seconds after object released and h stands for height. We're suppose to set the equation to 0 so far this is what I have: -16t^2 + 312 = 0 -8(2t^2+39)= 0 -8=0 can be disqualified but how do I factor out...

**physics**

A ball is released from a hot air balloon moving downward with a velocity of -10.0 meters/second and a height of 1,000 meters. How long did it take the ball to reach the surface of Earth? Given: g = -9.8 meters/second2.

**physics**

A ball is released from a hot air balloon moving downward with a velocity of -10.0 meters/second and a height of 1,000 meters. How long did it take the ball to reach the surface of Earth? Given: g = -9.8 meters/second2.

**physics**

A ball is released from a hot air balloon moving downward with a velocity of -10.0 meters/second and a height of 1,000 meters. How long did it take the ball to reach the surface of Earth? Given: g = -9.8 meters/second2.

**maths**

Mr john has 350 layers, on the average, each hen lays two eggs per day.how many eggs will he expect after six days?

**math **

Everett made 3/5 of the baskets he shot. Suppose he shot 60 baskets. How many did he make?

**math**

There is something wrong with this definition for a pair of vertical angles: “If AB and CD intersect at point P, then APC and BPD are a pair of vertical angles.” Sketch a counterexample to show why it is not correct. Can you add a phrase to correct it?

**Math**

The Product of 2 consecutive odd numbers is 783. What are the numbers?

**math**

Steve the answer according to my book is 147

**math**

Assume the average height and weight of a female in your math class is 5'5" and 140 pounds. Use this information to write a variation equation then use it to find the weight of the female below if they had the same body type as the average female. Round answer to the ...

**Math **

If I went to the bank and fianaced $81,000 at 9% for 25 years what would my monthly principal and interest payment be?

**world geography**

As of 2008, the population of Australia was 21.3 million, and the population of New Zealand was closer to ________ million

**Physics**

A block of mass m1=1.6kg, initially moving to the right with a velocity of +4m/s on a frictionless horizontal track, colides with a massless spring attached to a second block of m2=2.1kg moving left with a velocity of -2.5m/s. The spring constant is 600 N/m. A) assuming the co...

**math**

2/3 + 3/5= 5/6 - 3/4= 3/5 X 2/5= 1/2 DIVIDE 5/8=

**chemestry**

polycarbonate has a density of 1.2 g/cm3. a photo frame is constructed from two 3.00mm of polycarbonate.Each sheet measures 28 cm by 22cm. what is the mass of the photo frame?

**Physics**

A ball is fastened to one en of a 28 cm string, and the other end is held fixed to a support. The ball whirls in a horizontal circle. Find the speed of the ball in its circular path if the string makes an angle of 35 degrees to the vertical.

**Chemistry**

Calculate the pressure exerted by a 14.6 mol NH3g in a 3.2 L container at -15.0 celcius using the Van der Waals equation.

**chemistry**

calculate the heat energy required to raise the temperature of a 500. gram iron pipe from 25 degress celcius to 100 degrees celcius. the specific heat for iron is .45 J/g degrees celcius

**Biochemistry**

what's transcription?

**Biochemistry**

what's transcription?

**Biology**

Consider the close-up view of a segment of DNA undergoing transcription from left to right. Transcription begins at and includes the G/C base pair shown in bold green type.

**C/Justice**

Inmate Code refers to the rules and values that have developed among prisoners inside prisons social systems.[1] The inmate code helps define an inmate's image as a model prisoner. The code helps to emphasize unity of prisoners against correctional workers. This code highl...

**Chemistry**

Heating an ore of antimony (Sb2S3) in the presence of iron yields antimony and iron (II) sulfide. Sb2S3 + 3 Fe = 2Sb + 3 FeS When 15g of Sb2S3 reacts with 10g of Fe in the lab 9.84g of Sb is produced. What is the limiting reactant in this reaction? What is the theorectical yie...

**stat**

A set of n = 5 pairs of X and Y values has SX = 10, SY = 20, and SXY = 10. For this set of scores, what is the value of SP?

**science**

How long does it take to prepare 4.00 g of Al by electrolysis of Al2O3 using a current of 2.50 ampere?

**science**

If 2.7 moles of copper metal was deposited from a solution of Cu(NO3)2, how many electrons were involved?

**Physics**

An electric force of 3x10^-8N is produced from an electrostatic point charge of 4x10^-10. It is 40cm from another electrostatic point charge. What is the charge of the second point?

**Physics**

If an electric force of 550N is produced from two charges, one is 345C, the other is 125C. How far apart are the charges?

**math**

A jara has 25 green grapes and 75 purple grapes. what is the probability that a purle grape will be chosen at random?

**Physics**

You are standing on a beach and 5 wave crests land on shore in 50 seconds. Each wave is 32m apart. Find Frequency, period, wavelength and speed.

**math**

Between which two consecutive integers is the value of this irrational number? square root of 117? A. 8 and 9 B. 10 and 11 C. 14 and 15 D. 20 and 21

**math**

Max,Owen,Elise, and Cara went to a school carnival. They each played the dart throw,ring toss,water shoot,and basketball throw. Each student won a different game. CLUES:*Max didn't score any points at the dart throw. * Elise correctly tossed 2 rings, but did not win the ri...

**math**

Students submitted pictures for the school yearbook. Only 4/5 of the submitted pictures fit in the yearbook. There were 105 pictures that did not fit. Approximately how many total pictures were submitted for the yearbook? A. 105 B. 210 C. 420 D. 500

**math**

Emily,Zeke,Harry,& Brook each conducted surveys on the number of books people have in their homes. Then they answered the question below. "MUST ALL MEASURES OF CENTRAL TENDENCY APPEAR AS A NUMBER IN A SET OF DATA COLLECTED? A. Emily says this is always true because all th...

**math**

Which statement is true? A. All vertical lines have a slope of zero. B. All vertical lines have a slope positive slope. C. All vertical lines have a negative slope. D. All vertical lines have a undefined slope. WHY?

**math**

A box contains 4 red pencils, 3 blue pencils, and 3 yellow pencils. What is the probability that a student randomly selects a blue pencil, keeps it, then a second student randomly selects a yellow pencil? A. 1/10 B. 3/10 C. 6/10 D. 9/10

**math**

which shape will create tessellation using only translations? A. scalene triangle B. regular hexagon C. equilateral triangle D. isosceles trapezoid

**Statistics**

Weights of male mountain lions follow the normal distribution with a median of 150 lb and an interquartile range of 8.2 lb. Find the 75th percentile of the weights. Find the 95th percentile of the weights.

**Statistics**

An orchestra consists of 25 members. The youngest member is 32 years old. She leaves and is replaced by a new member who is 30 years old. By how much does the replacement change the average age of the members of the orchestra? By how much does the replacement change the median...

**Circles / Square**

dude steave ur wrong the answer has to be a square root...

**science**

Who made the first light bulb?

**Statistics**

How do you find the intercept?

**Statistics**

That answer is incorrect.

**Statistics**

A large number of children were surveyed. The table below shows the distribution of the time they spent watching TV in the week before the survey. Intervals include the left endpoint but not the right. You can assume that the times are uniformly distributed within each interva...

**Statistics**

Thanks I got it

**Statistics**

A class has 3 sections. Here is a summary of the scores on the final exam. Average SD Number of Students Section 1 68 9 20 Section 2 75 9 25 Section 3 60 9 32 Find the average score of all the students in the class.

**Statistics**

A large number of children were surveyed. The table below shows the distribution of the time they spent watching TV in the week before the survey. Intervals include the left endpoint but not the right. You can assume that the times are uniformly distributed within each interva...

**PHYSICS**

Suppose that the magnetic field in the figure below has a magnitude of 1.1 T, the rod has a length of 0.86 m, and the hand keeps the rod moving to the right at a constant speed of 3.4 m/s. If the current in the circuit is 0.044 A, what is the average power being delivered to t...

**chemistry**

does Adding A increased Q, so the net reaction proceeds to the left to decrease Q. a+b=ab

**chemistry**

what mass of ammonium chloride is dissolved in 100 grams water in each of the following solutions in 1.10 molal NH4Cl solution, in a solution which is 75% water by mass in solution with a mole fraction of 0.15 NH4Cl? please help me solve this problem. thank you!

**Economics**

There are 10 identical consumers whose demand is D: p = 20 - 10q. There are 10 identical firms, each firm's marginal cost is MC(q)= 5 + 5q. The market is competitive. a) derive the market demand function b) derive the market supply function c) what is the market equilibriu...

**Chemistry**

how did you solve it???

**math**

5(3x+2)+2(3x+2)

**english**

how do you write a persuasive essay about youny adult women and teen girls quitting abortion.

**math**

Samantha opened a savings account and deposited some money into the account. The account pays an annual simple interest rate of 5%. After 9 years, the interest earned on the account was $1,800. How much money did Samantha deposit in the account?

**English- edit my essay please?**

The Great Gatsby Mortality is something we will all face at some point in our life. However, I doubt many people will deal with it in the same light as James Gatz did. He died once in his youth, at the age of seventeen, only to be reborn again as someone entirely new and diffe...

**literary**

What does my teacher mean by this? So I'm writing an essay on the great gatsby and I told my teacher about it via emai. (I'm doing online school) and this is what he told me... Also, make sure you develop the theme more than merely "mortality." I always tell ...

**spanish III check?**

I wasn't sure if the other question posted because I put all the sections into one question and I thought that might have been too much. I'm still not sure how to navigate this site correctly. I mean, I found this question of mine by going through all of the spanish qu...

**spanish III check?**

1. En nuestra casa, mi hermana y yo preparamos la comida los fines de semana y _____ padres la preparan durante la semana.--- NUESTROS 2. Tiene que preparar mucha comida porque tengo cinco hermanos y mis hermanos pueden comerse un millón de enchiladas. ¡____famili...

**spanish III**

check? I was unsure how to do this part... I still put the answers. Will you correct them if they are wrong and explain to me how to do it right? Thanks! Son las tijeras de nosotros. Son____________ tijeras.Son los gatos de la Sra. Barbosa.---- NOSOTROS Son____________ gatos.E...

**spanish**

I gave you everything my teacher gave me... Maybe that's why I'm so confused? Thank you for all your help though! It means a lot. I appriciate it!

**spanish**

thank you!!

**spanish**

I have the answers... will you tell me if theyre right?? Choose the correct form of the possessive adjective. Modelo: amigos (mi or mis) - mis - amigos is plural Libro- A. SU b. sus 2. Casas A. NUESTRAS b. nuestra 3. Cena a. sus B. SU 4. Sombrero A. TU b. tus 5. Guantes A. TUS...

**algebra**

At a crime scene, police officers find a murder victim in a tub full of warm water. A thermometer shows that the water temperature is 75 degrees F and the air temperature is 70 degrees F. It is known that most people fill a tub with water at 100 degrees F. Find Newton's La...

**algebra**

In an episode from the TV show Futurama, Phillip J. Fry had $0.93 in his bank account in 2000. In the year 3000 it had grown to $4.3 billion! What was the percent interest rate (to three decimal places) if it had been continuously compounded? What was the percent interest rate...

**algebra**

Beer cans are right circular cylinders. My Algebraic Ale and Logarithmic Lager cans, from the Schmidt Brewery, have dimensional units called "brewskies". They have a volume (in cubic brewskies) equal to the solution of the number of grams of radium 226 remaining afte...

**algebra**

The radioactive isotope you discovered at 8 a.m weighed 75 mg. You named it "Nerdium." At 3 p.m. it measured only 0.009 grams. What is its half-life?

**algebra**

At a crime scene, police officers find a murder victim in a tub full of warm water. A thermometer shows that the water temperature is 75 degrees F and the air temperature is 70 degrees F. It is known that most people fill a tub with water at 100 degrees F. Find Newton's La...

**AP us history**

REALLY?! Man... What's wrong with the others? I was positive they were right.

**AP us history**

I have the answers will you just tell me if I'm right? This is for my final study guide. The Compromise of 1850 affected which states an/or Territiries? A. Texas, New Mexico, California B. Utah, Texas, California C. CALIFORNIA, OREGON, AND MISSIOUR D. Texas, arkansas, miss...

**math**

Olive Oyl sent Popeye and Wimpy out to get spinach and burgers. They bought the following combination: If the square of the number of burgers is doubled and added to the square of the number of cans of spinach, the total equals 59. When the square of the number of cans of spin...

**Chemistry**

A p-n junction is to be created by diffusing boron (B) into an n-type silicon wafer with an existing carrier concentration of 1015/cm3. The location of the junction will be 6μm below the surface of the wafer. The surface concentration of boron will be maintained at 1020/c...

**Chemistry**

To increase corrosion resistance, chromium is diffused into steel at 980∘ C. If the surface concentration of Cr is maintained constant at 100%, how long will it take (in days) to achieve a Cr concentration of 1.8% at a depth of 0.002 cm below the steel surface? (D0=0.54 ...

**Chemistry**

A p-n junction is obtained at a depth of 3×10−3 cm by diffusion of antimony (Sb) into p-type germanium. What is the acceptor concentration in the bulk Ge, if diffusion was carried out for three hours at 790∘ C? Given: Constant Sb surface concentration is 8&ti...

**Chemistry**

The Gaussian error function can be approximated for small values of x as erf(x)≈x. Suppose a silicon wafer is exposed to aluminum vapor at 1300∘ C. At what distance (in centimeters) will the concentration of Al be 35% of the surface concentration in 164 hours? Assu...

**Chemistry**

(a) Certain alloys such as LaNi5 can store hydrogen at room temperature. A plate of LaNi5 containing no hydrogen is placed in a chamber filled with pure hydrogen and maintained at a constant pressure. At what depth from the surface will the concentration of hydrogen be 1/2 the...

**Chemistry**

You wish to remove nitrogen from the near-surface region of a plate of cobalt which is 1.0 cm thick. The plate is placed in a furnace at 417∘ C where an atmosphere of H2 and NH3 reacts with the nitrogen in the cobalt and fixes the surface concentration to 111 ppm (parts ...

**Chemistry**

An undesirable consequence of welding steel by acetylene torch is the rise in hydrogen concentration in the metal. That hydrogen contamination embrittles the steel. The metal is typically subjected to a vacuum heat treatment to restore ductility. A steel part is placed in a va...

**Chemistry**

Carburization" of pure iron (Fe) is carried out at 950∘ C. It is desirable to achieve a carbon content of 0.9% at a depth of 0.1 mm below the surface. A constant supply of carbon at the surface maintains a surface concentration of 1.2%. Assuming the diffusivity of c...

**geometry**

10 and 2 - 3

**psychology**

hello, can you help me try to find research for sigmund freud unconscious mind thank you

**Physics**

There is a door that is 1.0 m wide and can rotate about a vertical axis without friction. The door’s mass is 15 kg and is free to swing open. Someone fires a 10 g bullet at 400 m/s into the exact center of the door, perpendicular to it. Find the angular velocity of the do...

**Algebra**

a helicopter that is 200 meters above the ground descends at a rate of 2 meters per second. The altitude of the helicopter after t seconds is given by h(t)=2000-2t. 1)give the range of this function 2)give the domain of this function.

**Algebra**

Joyce combines 9 atoms of hydrogen and 3 atoms of nitrogen to make 3 molecules of ammonia. write a direct variation equation which relates atoms of hydrogen to atoms of nitrogen. How many nitrogen atoms does Joyce need to form ammonia molecules using 51 hydrogen atoms?

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