Wednesday

April 23, 2014

April 23, 2014

Total # Posts: 293

**Physics**

I've been working on this problem for close to an hour now and keep getting very wrong numbers... The two objects with different mass (m1 = 5.0 kg and m2 = 3.0 kg) in the Atwood's machine shown in the figure are released from rest, with one object at a height of 0.91 m...

**Elementary Statistics**

There are 100 questions from an SAT test, and they are all multiple choice with possible answers of a,b,c,d,e. For each question, only one answer is correct, find the standard deviation for the numbers of correct answers for those who make random guesses for all 100 questions.

**problem solving - math**

the men are camping 45 miles due west and then go 60 miles directly north. if they can cover 18 miles a day how long will it take them to reach the railroad?

**problem solving - math**

timothy owns 13 chains, each chain having 3 links. timothy wants to use all the small chains to make one circular chain of 39 links. he needs 4 minutes to cut open a link and 10 minutes to close it by smoldering. timothy makes the big chain in 140 minutes. how?

**problem solving - math**

3 persons are to divide among themselves 21 equal cask, of which 7 are full, 7 are half full, and 7 are empty. how can an equitable division be made, without pouring the wine from any cask into any other, in such a way that each person receives the same amount of wine and the ...

**advance math**

an aquarium is in the shape of a right rectangular prism. each side of the aquarium is a rectangle that is 10 in wide and 8 in high. when the aquarium is tilted, the water in it just cover an 8 in by 10 in end, but only three-fourths of the rectangular bottom. find the depth t...

**discrete mathematics**

how many baseball games of single elimination must be played by 421 teams in a tournament before a winner is determined

**algebra**

that's my problem i do not know how to simplify.

**algebra**

a teacher reported 1/5 made A's, 1/4 made B, 1/3 made C's, 1/6 made D's, and 12 made F's How many are in the class Let X = the number of students 57/60 + 12 -------

**college physics**

a tennis ball is thrown straight up with an initial velocity of 22.5 m/s. it is caught at the same distance above the ground. a). how long does it take to reach its maximum height? b). how high does the ball rise? c). at what speed does it hit the ground? d). what total length...

**Chemistry**

Yes, I used it for my calculations. Thank you.

**Chemistry**

Oh wow. I just misread the standards the question was asking for. I was trying to make a 1.00M solution rather than a 1x10^-3M. I hope this is what my professor means with the way the question was written.

**Chemistry**

You have a stock 0.100 M solution of KMnO4 and a series of 100-mL volumetric flasks. What volumes of the stock solution will you have to pipet into the flasks to prepare standards of 1.00, 2.00, 5.00, and 10.0x10^-3M KMnO4 solutions? I tried using M1V1=M2V2 but the answers did...

**Calculus**

Thank you!

**Calculus**

I've been trying to solve the improper integral of ln(x)/sqrt(x) dx as a=1 and b=infinity I am required to solve for this question and according to my answer, it is divergent. However, my answer is infinity-4. Is it acceptable to say that infinity minus a number is simply ...

**Chemistry**

Awesome, thank you so much for the help!

**Chemistry**

I need help in solving this problem: A certain substance has a heat of vaporization of 42.46 kJ/mol. At what Kelvin temperature will the vapor pressure be 5.00 times higher than it was at 291 K? I know that I have to use the Clausius-Clapeyron equation, but what would I be sol...

**Chemistry**

One of my homework problems deals with finding the change in entropy of the surroundings using the equation delta(S)= -delta(H)/T(temp.) The numbers given were T=263K and delta(H)fusion=6.0*10^(3) J/mol I know how to solve the problem, I just want to know why it is that even t...

**Calculus Problem**

Thank you so much for showing the steps, I really appreciate the help! (:

**Calculus Problem**

I need to find the integral of e^(2x)sin(3x) I used integration by parts and I let u=e^2x and dv=sin(3x) My final answer was (-3/8)(e^(2x))(cos(3x)) - (1/8)(e^(2x))(sin(3x)) but it's wrong. Please help!!

**Calculus**

Evaluate the definite integral. dx/(x*sqrt(lnx)) from 1 to e^4 I'm having trouble figuring this out, I might be overthinking it. The way I've approached this is by using u substitution and letting u=lnx. I keep getting the wrong answer though. Help is appreciated!!

**Calculus**

Figured it out. Turns out my b=4 not 2.

**Calculus**

The region between the graphs of x=y^(2)and x=2y is rotated around the line y=2. The volume of the resulting solid is... I've tried this five times and no luck. Please help. I think my a=o and b=2. I would appreciate the help.

**Calculus**

Never mind! I figured it out!

**Physics**

Which of the following equations describes the condition for observing the fourth bright fringe in Young's double-slit interference pattern? Assume n = 0 for the central bright fringe. Which of the following equations describe the condition for observing the fourth dark fr...

**Physics**

Thank you so much

**Physics**

Okay so then 1(sin45) = 1.33(sinx) I got 32.04degrees?

**Physics**

What is the angle of refraction of a light ray that enters the surface of a calm lake from air at an angle of 45o to the normal? The refractive index of water is 1.333. I don't even know how to start this or what the formula is. Thanks for your help in advance. It really i...

**Physics**

A water wave is generated in a ripple tank by an oscillator that vibrates 50 times in 30 seconds. A given trough of the wave travels 50.0 cm in 15 seconds. What is the wavelength of the water wave? Produce all your workings. I got 50/30 = 1.67 vibrations per second = frequency...

**maths-urgent**

price of a home is 164,000. bank requires a 20% down payment and 3 points at closing. the cost of the home is financed with a 30 year fixed rate mortgage at 9%

**maths-urgent**

price of a home is 164,000. bank requires a 20% down payment and 3 points at closing. the cost of the home is financed with a 30 year fixed rate mortgage at 9%

**math**

In a right triangle, if sin ø = (5/13), what is the value of csc ø?

**Physics**

A person's body is producing energy internally due to metabolic processes. If the body loses more energy than metabolic processes are generating, its temperature will drop. If the drop is severe, it can be life-threatening. Suppose a person is unclothed and energy is being...

**college algebra**

that's what I got. thanks

**college algebra**

sorry that should be x^2+y^2+16x-18y+145=25 Been up to long working on this. Again I am sorry!!

**college algebra**

Can someone please help me find the x-intercepts and y-intecepts of this equation. I have the radius, and center but I can't seem to get the intercepts. x^2+y^2=16x-18y+145=25 Please show work. Thanks!!

**college algebra**

I am having to explain how to find the domain and range of a rational function from its graph. Can someone help me to try and put this into simple terms.

**college algebra**

find functions f anf g so that fog equals H H(x)=ãx^2+17 please show work

**college algebra, Please help!!**

find the domain of the composite function of fog f(x)=x^2+8;g(x)ãx-5

**college algebra, Please help!!**

solve the following equation 9^x-1 = 144(6x) please show work.

**college algebra**

use the properties of logarithms to find the exact value of the expression loglower 3^18 - log lower3^6 **how do I make the three lower in the log equation?

**college algebra**

solve the following exponential equation. 7^x=8 a. x= Write in exact solution b. then with that answer move the decimal 3 points over

**Physics**

On an extra note. I've done a lot of the practice problems and gotten those wrong... I don't know why I keep getting this wrong... But my answers for part a have been fairly close it seems like I keep getting my y-speed when the engine fails wrong by about 2.something ...

**Physics **

A rocket is launched at an angle of 56.0° above the horizontal with an initial speed of 103 m/s. It moves for 3.00 s along its initial line of motion with an acceleration of 31.0 m/s2. At this time its engines fail and the rocket proceeds to move as a free body. (a) Find t...

**Economics**

I am looking for an answer to this very same question with a different dollar amount "If the average adult produces $70,000 of output per year, how much output is lost annually as a result of adult deaths from secondhand smoke?" according to the news/study provided b...

**college algebra--need help please!!**

solve the equation in the real number system. 2x^4-23x^3+75x^2-88x+28=0 What are the real solutions of the equations? please show work. I do not know how to work this at all

**algebra**

use the rational zero theorem to list the potential rational zeros of the polynomial function. Do not attempt to find the zeros. f(x)=2x^7-x^5+8x^4+52

**college algebra--please help**

Find a bound on the real zeros of the polynomial f(x)=x^4+4x^3-8x-6 can someone help me, I am confused and don't know where to start.

**probability please help!!**

A fair, six-sided die is rolled eight times, to form an eight-digit number. What is the probability that the resulting number is a multiple of 8? Express your answer as a common fraction. I think the last 3 digits have to be divisible by 8 to be a multiple of 8...

**college algebra**

i am not understanding why you put 0 for the first answer. it doesn't seem like you added or did any type of math to get the 0. can you explain more. this is all confusing to me.

**college algebra**

we would let f(x)=x^3-7x^2+25x-39 = 0. we would factor to get (x-3)(x^ 2-4x+13). find the solutions to the second part (x^2-4x+13)using the quadratic formula. (the first part is x=3)

**social studys**

why do CHRISTIANS and MUSLIMS want the HOLY land? CHRISTIANS MUSLIMS HOLY

**social studys**

An estate of land, esp. one held on condition of feudal service

**probability - confused**

A fair, six-sided die is rolled eight times, to form an eight-digit number. What is the probability that the resulting number is a multiple of 8? Express your answer as a common fraction. I think the last 3 digits have to be divisible by 8 to be a multiple of 8...

**Chemistry**

For each of the bonds listed below use hybridized orbitals to classify the type of sigma bond that is formed between the two atoms. a) The sigma bond between boron and hydrogen in BH3 answer: sp^2 - p b) the sigma bond between S and fluoride in SF4. answer: sp^3d - p I underst...

**General Chemistry**

An electron in a hydrogen atom relaxes to the n = 4 level, emitting light of 114 THz. What is the value of n for the level in which the electron originated? I am halfway through, but uncertain as to how to simplify the problem to completion. (6.63 x 10^-34 J x s)(1.14 x 10^14 ...

**Physics**

When the pendulum bob reaches the mean position, the net force acting on it is zero. Why then does it swing past the mean position?

**Physics**

Light cannot be linearly polarized by: transmission reflection diffraction diffraction

**Physics**

Which combination of primary additive colors will produce yellow-colored light? green and blue blue and red red and green cyan and magenta

**Physics**

Which of the following is an example of diffuse reflection? light reflected from the surface of a dry asphalt roadway light reflected from the surface of a calm lake light reflected from the surface of glossy paper light reflected from the surface of a shiny metal plate

**Physics**

When the pendulum bob reaches the mean position, the net force acting on it is zero. Why then does it swing past the mean position?

**Physics**

A tennis ball is dropped from 1.80 m above the ground. It rebounds to a height of 1.00 m (assume down to be negative). (a) With what velocity does it hit the ground? (b) With what velocity does it leave the ground? (c) If the tennis ball were in contact with the ground for 0.0...

**Advanced physical science**

An astronaut drops a golf ball to the surface of the moon from a height of 1.5m. The golf ball has a velocity of 2.24 m/s right before it lands on the moon (assume this height to be zero). What is acceleration due to gravity on the moon?

**Advanced physical science**

At the top of the Washington monument, a bird drops an acorn into the reflecting pool 169m below. If the acorn has a massof 1.0 kg, with what velocity would it hit the water?

**Advanced physical science**

A fiery ball of wood is loaded into a medieval catapult to be thrown into a castle. Unfortunately, the attacking heathens are not very smart and since geometry and physics were not studied in their time, they launched the ball straight up into the air. The catapult launcher si...

**APS**

The Marshmellow man tromps along the streets of New York City with his blue sailor hat on. He tries to climb up a building to reach Ghostbusters and a gargoyle statue falls 326m to the street below. What height is the gargoyle when it reaches a velocity of 59 m/s?

**APS**

Ben eats a bowl of rice as he walks across the San Francisco Bridge. When he is finished, he drops his empty bowl 67m down to the bay water. What speed does it hit the water with?

**chemistry**

Provide a synthesis of the following aldehyde starting from ethylene. Show the reagents and products for each step. H2C=CH2 --> CH3-CH2-CH=O Try to be as clear as possible. Thanks!

**Chemistry**

What alkane effuses at 1/5 the rate of He

**economics**

In the following examples, state how you would use the principle of marginal analysis to make a decision. a. Deciding how many days to wait before doing your laundry b. deciding how much library research to do before writing your term paper c. Deciding how many bags of chips t...

**Geometry**

I get it now! However, I think you made a mistake with .16=1-b^2/4. It should be turned into .64=1-b^2, and then b^2=0.36. Then x^2/4 + y^2/0.36=1.

**Geometry**

For an ellipse, one focus is (0,0), one vertex is (2,0), and the eccentricity is 0.4. How do I find the equation for the ellipse? It seems like I have so little information!

**Physics**

Thank you!

**Physics**

dev.physicslab. org/asp/nyregents/2003/January/part3.asp Why is the answer to #47 2 amperes? How do I get that?

**physics A**

A net charge of 47 mC passes through the cross-sectional area of a wire in 19.0 s. (a) What is the current in the wire? 1 A (b) How many electrons pass the cross-sectional area in 1.0 min? 2 . electrons

**Chemistry**

Thanks for the table! It actually is in my text, but I am taking the AP test soon, so I won't have a table like that. I can only answer the question based on the periodic table and that's it. Is there anything else I can use to at least eliminate the other choices?

**Chemistry**

Adding water to some chemicals can be dangerous because large amounts of heat are liberated. Which of the following does NOT liberate heat when water is added to it? KNO3 (the answer) NaOH Na CaO H2SO4 I guessed Na simply because it's the only one that's an element, bu...

**Chemistry**

I think I get it, but just to clarify... Because we have a power supply, we know we have an electrolytic cell, which needs energy from an external source. For electrolytic cells, cathodes are considered the negative electrodes. If K+ and H20 go to the cathode, they get reduced...

**Chemistry**

A direct-current power supply of low voltage (less than 10 volts) has lost the markings that indicate which output terminal is positive and which is negative. A chemist suggests that the power supply terminals be connected to a pair of platinum electrodes that dip into 0.1-mol...

**Chemistry**

A 0.5224g sample of an unknown monoprotic acid was titrated with 0.0998M of NaOH. The equivalence point of the titration occurs at 23.82 mL. Determine the molar mass of the unknown acid.

**chemistry**

Hi Dr. Bob! I actually cleared it all up, but thank you!

**chemistry**

Hello, I have data here: tube # Contents Initial color (after 2 drops of universal indicator) Color after adding HCl Color after adding NaOH (after the HCl had been poured) 1 CO32-/HCO3- Dark purple Purple Purple 2 CO32-/HCO3- Dark purple -- -- 3 HCH3CO2/C H3CO2- red Light red...

**Chemistry**

Thanks so much! I get it now!

**Chemistry**

Hi Dr. Bob, When I do that, I get 11.30 as the pH, although I don't think that's it. Did I miss something?

**Chemistry**

HOBr (aq) <----> H+ (aq) + OBr- (aq), Ka = 2.3 x 10^-9 Hypobromous acid, HOBr, is a weak acid that dissociates in water, as represented by the equation. (a) Calculate the value of [H+] in a solution of HOBr that has a pH of 4.95. Ans: 1.1 * 10^-5 M (b) Write the equilibr...

**Math**

Help with identify the property 45x6=(40+5)x(5+6)= I think Assoiative prop. ( is this correct?) 6x1=6 I put identity prop. of 1 4+(6+5)=(4+6)+5= distributive prop. 8+(-8)=0 I put identity prop. of 0 5x4=4x5 I put communtive property Can you tell me if I have them correct? Thanks

**math**

A sample survey of 50 people in Harrisburg, PA indicates that 10 of them know the mayors name in the neighboring city. Out of 5,500 Harrisburg residents, how many would you predict know the name of the mayor of the neighboring city? I thought 1100. I did 10/50=x/5500, is this ...

**physics **

A spherical conductor has a radius of 14.0 cm and charge of 26.0 µC. Calculate the electric field and the electric potential (a) r = 10.0 cm, (b) r = 20.0 cm, and (c) r = 14.0 cm from the center. how do i calculate k?

**physics HELP MEEE SO CONFUSED**

A spherical conductor has a radius of 14.0 cm and charge of 26.0 µC. Calculate the electric field and the electric potential (a) r = 10.0 cm, (b) r = 20.0 cm, and (c) r = 14.0 cm from the center.

**Physics**

I have to create a teaching aid for physics based on the principles i have learnt like gravitation , mechanical properties and many more. I am not able to find the right experiment to demonstrate infront of my teacher.Please help me deal with this by providing information abo...

**Physics**

I have to create a teaching aid for physics based on the principles i have learnt like gravitation , mechanical properties and many more. I am not able to find the right experiment to demonstrate infront of my teacher.Please help me deal with this by providing information abou...

**Act Question**

all distances are in feet and all are right angles. a straight line drawn from point w to point z would be how long in feet?

**business**

For this question, use the information for Sports Baseballs, Inc. Sports Baseballs, Inc. is a corporation that manufacturers and sells baseballs across several states in the Southeast. It had sales of $2.7 million during the last year. Expenses were as follows: Cost of goods s...

**Math**

how can you break apart arrays when you multiply by 3?

**chemistry**

If you filled three balloons with eaqual volumes of hydrogen, argon, and carbon dioxide gas all at the same temperature and pressure, which ballon would weigh the most? The least?

**chemistry**

What mass of hydrogen peroxide should result when 1.50g of barium peroxide is reacted with 25.0mL of 0.50 M hydrochloric acid?

**chemistry**

a better understanding of how she got the answer

**chemistry**

Jenny please show me in better detail the set up of the answer.

**chemistry**

If you make a solution by dissolving 25.0g of sodium chloride in 100.0 mL of water. What is the boiling point of the solution?

**math**

A woman is sitting in a boat at anchor on a lake. Her boat bobs up and down once every 2.0·s. She notices that when the front of her 3.0·m long boat is at one wave crest, a second crest is at the middle of her boat, and a third is at the end. What is the frequenc...