Friday

April 29, 2016
Total # Posts: 1,724

**math**

1.A wind turbine has blades 50m in diameter and an overall height of 125m. If it has four blades instead of three, create four equations modelling the height of a point on the tip for each of the four blades. 2.Create a sine equation for the height of a point as shown below. ...
*April 25, 2016*

**Science/Math**

A car is travelling at a speed of 30.0m/s encounters an emergency and comes to a complete stop. How much time will it take for the car to stop at -4.0m/s^2
*April 22, 2016*

**Chemistry **

t takes 572 kJ of energy to decompose 2.00 mol of liquid water. How much energy does it take to decompose 54.0 mol of water? 2H2O(l)+572kJ→2H2(g)+O2(g)
*April 18, 2016*

**Chemistry **

The estimated proven world oil reserves in 2013 were 1526 billion barrels. The world annual rate of use was 32.6 billion barrels. How long will these reserves last if this rate of use continues? (The rate of use is actually likely to increase.)
*April 18, 2016*

**Chemistry **

Burning 2.00 mol of hydrogen releases 483.6 kJ of energy. Determine how much energy, in kilojoules, must be supplied to convert 5.00 mol of water vapor into hydrogen gas and oxygen gas.
*April 18, 2016*

**Chemistry**

Calculate the number of moles Fe2O3 in 2.37x10^21 atoms of Fe2O3?
*April 12, 2016*

**Chemistry **

Radium-223 has a half-life of 11.4 days.Approximately how long would it take for the activity of a sample of 223Ra to decrease to 2.00 % of its initial value?
*April 8, 2016*

**Chemistry **

If it takes 45 days for 80.0 mg of a particular radioactive isotope to decay to 10.0 mg what is its half-life?
*April 8, 2016*

**Chemistry **

A radionuclide undergoes alpha emission, and thorium-234 is produced. What was the original radionuclide?
*April 8, 2016*

**Chemistry **

Radium-223 nuclei usually decay by alpha emission. Once in every billion decays, a radium-223 nucleus emits a carbon-14 nucleus. Write a balanced nuclear equation for alpha emission. Write a balanced nuclear equation for carbon-14 emission.
*April 8, 2016*

**Math**

The temperature went from 83'F at noon to 72'F at midnight. What is the percent of decrease in the temperature from noon to midnight?
*April 4, 2016*

**Microeconomics **

You are asked to examine the market for luxury housing in the southern Westchester town of Quietville. This kind of housing is said to be a normal good. In Quietville a substantial proportion of the people who buy luxury homes are people who work in the financial sector on ...
*March 14, 2016*

**Chemistry **

I need help on this question. Identify the mistakes in the following balanced equations. Rewrite the equation to make it correct. Each question has one mistake to correct. a) C9H20+12O2 -> 9CO2 + 10H2O b) H2+Cl -> 2HCl
*March 13, 2016*

**Common core standard. math**

Consuelos living room is in the shape of a rectangle and has an area of 360 square feet. The width of the living room is 5/6 it's length. What is the length of living room?
*March 8, 2016*

**Physics**

A 600W flashlamp fitted to a camera is operated by discharging a 10 000 uF capacitor through the lamp. The capacitor is charged initially from a 6V battery. Calculate A) the energy stores in the capacitor when fully charged B) the duration of the flash
*February 11, 2016*

**chemistry**

an ezyme -catalysed reaction was carried out in a solution buffered with 0.05 M phosphate ph 7.2 . As a result of the reaction ,0.06M of acid was formed. (phosphoric acid has three pka values. The one required for this calculation is pka2=7.2). 1) what was the pH at the end of...
*January 12, 2016*

**Science**

So the oceans would gravitate to other locations, altering the geography of the planet and the tides would be weaker? or would the tides be stronger, or remain the same?
*December 18, 2015*

**Science**

This is an actual question on my homework...
*December 18, 2015*

**Science**

What would happen to ocean tides on Earth if Earth stopped rotating?
*December 18, 2015*

**Physics**

A golfer rides in a golf cart at an average speed of 3.93 m/s for 43.3 s. She then gets out of the cart and starts walking at an average speed of 1.13 m/s. For how long (in seconds) must she walk if her average speed for the entire trip, riding and walking, is 1.99 m/s? Can ...
*December 17, 2015*

**Finite Math**

What is the coefficient of y^14 in the expansion of (x+y)^14? What is the coefficient of xy^13 in the expansion of (x+y)^14? What is the coefficient of x^2y^12 in the expansion of (x+y)^14?
*December 10, 2015*

**Finite Math**

Pete's Pizzeria offers 30 different pizza toppings. How many 3 topping pizzas are possible (assuming the toppings are distinct)? If we allow any number of toppings (all distinct), including none, how many different pizzas are possible?
*December 10, 2015*

**Finite Math**

At a local ice cream shop, you can choose from a collection of 11 different toppings. If you want to choose at least one topping, how many different topping combinations are possible (assuming no repeat toppings)?
*December 10, 2015*

**Finite Math**

At Sally's Salads, there is an all you can eat salad bar. You may choose one of 3 different lettuces, any number of 11 vegetable toppings, and at most one of 6 dressings. Suppose a salad is made at random following those rules. If the salad includes a lettuce choice, but ...
*December 10, 2015*

**Statistics need help**

Need help please on these questions: 1. A poll at Steve's high school was taken to see if students are in favor of spending class money to expand the junior-senior parking lot. Steve surveyed 6 random students from the population. 85% favored the expansion, while 15% ...
*November 25, 2015*

**Statistics**

One last one. A poll at Steve's high school was taken to see if students are in favor of spending class money to expand the junior-senior parking lot. Steve surveyed 6 random students from the population. 85% favored the expansion, while 15% opposed it. a) Determine the ...
*November 25, 2015*

**Statistics**

And need help on thos one: You have a bag of marbles containing 4 blue marbles, 5 red marbles, and 3 green marbles. What is the theoretical probability of pulling a red marble? Run an experiment to see how long it takes you to pull a red marble (you don't have to use ...
*November 25, 2015*

**Statiatics**

Need help please. Determine whether each experiment is a binomial experiment or can be reduced to a binomial experiment. If so, describe a trial, determine the random variable, and state n, p and q. a) You roll a die 15 times and find the sum of all the rolls. Just need this ...
*November 25, 2015*

**Math**

The mass of a box with 6 tennis balls is 2 kg 40 g. The same box with 10 tennis balls is 3 kg 160g. What is the mass of the empty box?
*November 18, 2015*

**Math**

Rope p is 3 times as long as rope q. Rope q is 1m 10 cm shorter than rope r. Rope r is 1 m 30 cm shorter than rope p. What is the length of rope q? Express your answer in meters and centimeters
*November 18, 2015*

**math**

Given that 2<=f(x)<=3 for -5<=x<=1, use a property of definite integrals to find an interval in which the value of interval sign{-5}^{1} f(x)dx lies.
*November 17, 2015*

**chemistry**

how many grams of NaCl should be added in 15ml which must have a final concentration of 10mM
*November 17, 2015*

**math**

Given that 2<=f(x)<=3 for -5<=x<=1, use a property of definite integrals to find an interval in which the value of interval sign{-5}^{1} f(x)dx lies.
*November 17, 2015*

**calc 2**

Consider the 4 leaf rose and a circle having polar equations: r=10cos(2Θ) and r=5 with 0≤Θ≤2π, respectively. Find the area of the region that lies inside the rose and outside the circle. hint: find the smallest positive value of Θ for which the ...
*November 15, 2015*

**calc 2**

A spherical tank of radius a feet is buried in the ground. The top of the tank lies b feet below the surface of the ground.(δ=64lbs/ft^3)Find a definite integral whose value equals total work done in emptying the tank through a pipe whose opening is at ground level. I ...
*November 15, 2015*

**Math**

A. X+4 B. X+4=12 When x=8
*November 14, 2015*

**Math**

A. X+4 B. X+4=12 When x=8
*November 14, 2015*

**Math**

Sarah has about containing x ribbons and 4 extra ribbons. Jill's has 12 ribbons. Express the number of ribbons that Sarah has in terms of x. For what value of x will Sarah and Jill have the same number of ribbons?
*November 14, 2015*

**Math**

Matt has y yards fabric. She used 2 yards to sew a skirt. She used the remaining fabric to make 5 jackets. Find the amount of material that was used to make each jacket in terms of y
*November 14, 2015*

**Math**

Debbie has a box containing y ribbons and 4 extra ribbons. Janine has 12 ribbons. Express the number of ribbons that Sarah has in terms of y. For what value of y will Debbie and Janine have the same number of ribbons
*November 14, 2015*

**Mcmath**

19 less than one-half of some number w, w" it's alsgebraically don't understand. Help please
*November 14, 2015*

**math**

Determine the standard matrix D of the linear mapping G: R^2-->R^2 that first rotates points clockwise through pi/6 radians and then reflects points through the line x2=x1
*November 11, 2015*

**math**

Determine the standard matrix D of the linear mapping G: R^2--R^2 that first rotates points clockwise through pi/6 radians and then reflects points through the line x2=x1
*November 11, 2015*

**Therochem**

What will the rate of reaction be when [IO3-] = 0.20 mol/L, {i-] = 0.40 mol/L, and [H+] = 0.10 mol\L ?
*November 4, 2015*

**trigonometry **

please help two boundary lines of a piece of property intersect at an angle 85 deg.. it is desired to cut off a triangular portion of the property which will be one acre (43560 sq. ft.) in area by means of a straight fence. If the fence begins at a point on one boundary 250 ft...
*November 4, 2015*

**Pre-algebra**

me too
*November 2, 2015*

**health**

Well, at least I got something that I didn't know right! I mean, I do D.T and Business Studies as GCSE's and the last thing that I did about health was in Year 9.
*November 2, 2015*

**health**

I know nothing about Health, but I know that Depression can be caused by a multitude of factors, such as the environment, mourning, and genetic issues, but there is no known cause, as it varies from person to person.
*November 2, 2015*

**English**

Ah... one problem, I don't have much time to do it in, as it is in tomorrow
*November 2, 2015*

**English**

I need to write a 4 stanza love poem for English homework, one problem, I'm rubbish at poems and haven't put pen to paper yet... HELP!!
*November 2, 2015*

**Science**

There is simply more mass for the heat energy to transfer to in a larger object than a smaller one.
*November 2, 2015*

**Reading**

I think that Ms. Sue is right
*November 2, 2015*

**physics**

rpm stands for rotations per minute, and 20 seconds is 1/3 of a minute, so divide 140 by 3 and you will have your answer!
*November 2, 2015*

**maths**

me neither
*November 2, 2015*

**english**

What, like Scooby-Doo in that movie with dinosaurs?
*November 2, 2015*

**Science**

Does anyone know the answers to this test
*October 30, 2015*

**Statistics**

Find the indicated probability: P(z<0.18 or z>2.13) I'm stumped and can't find material on how to do this anywhere. I can do something like P(0.18>z<2.13) but not this. PLEASE HAAALLLP!
*October 29, 2015*

**math**

the square root of 23 over 3 is equal to a) square root of 3 b)3 c)9 d)12 I found no one poof these answers to be true.
*October 27, 2015*

**Math**

A rectangular box is to have a square base and volume of 78 feet cubed. If the material for the base costs $.30 per square feet, the material for the sides costs $.10 per square foot, and the material for the top costs $.20 per square foot. Determine the dimensions of the box ...
*October 13, 2015*

**maths**

marc is looking at the plans for his new garage. the length of the garage is 8 metres. the scale of the drawing is 1:50 what will the length of the garage be on the drawing? which would be the most simplistic form for me to work this out, i really struggle ??
*October 10, 2015*

**maths**

Rosie is training for the next football match. She runs around a circular track with a radius of 60 metres. Use π = 3.14 and C = π d How far has Rosie run?
*October 10, 2015*

**maths**

Millie, Josh and Libby receive a bonus at work. They are paid in the ratio of 2:3:4 Josh's share is £105. What was the total amount of the bonus before they shared it?
*October 10, 2015*

**Physics**

You are standing on the roof of a building 300 m high, and throw a stone upward at 25 m/s. Find the speed of the stone as it strikes the ground.
*October 5, 2015*

**Algebra**

The path of a diver is given by y=-4/9 x^2 + 24/9x +12 where y is the height (in feet) and x is the horizontal distance from the end of the diving board (in feet). What is the maximum height of the diver?
*September 29, 2015*

**Physics**

Plzz help
*September 27, 2015*

**Physics**

In the figure below the left-hand cable has a tension T1 and makes an angle of 45 ◦ with the horizontal. The right-hand cable has a tension T3 and makes an angle of 48 ◦ with the horizontal. A W1 weight is on the left and a W2 weight is on the right. The cable ...
*September 27, 2015*

**Science PLEASE HELP**

yes
*September 27, 2015*

**Science PLEASE HELP**

Could a mixture be made up of only elements and no compounds? Explain.
*September 27, 2015*

**math**

The tenths digit of ds decimal is the smallest prime n.The hundredths digits is twice the tenths digit is the GCF 18 and 27.
*September 22, 2015*

**Math**

simplify each expression 14 + 5(x + 3) - 7x 34 - 7x
*September 21, 2015*

**Physics**

.3 ft
*September 9, 2015*

**Physics**

A point charge of 4 μC is placed at the origin. There is an external uniform field E = 400 i N/C. What is the net force on a 5 μC charge placed at (5 m, 3 m) ??? i + ??? j N
*September 8, 2015*

**Chemistry **

To prepare 500.00 mL of 0.300 M buffer with a pH of 7.4. NaH2PO4/Na2HPO4 How many grams of each should be added to the 500.00mL flask to create this buffer?
*September 8, 2015*

**Chemistry**

During the operation of a bunsen burner, a chemical reaction occurs. This chemical reaction is represented by the chemical equation below: methane + oxygen - carbon dioxide +water. During this chemical reaction, methane and oxygen are converted into carbon dioxide and water. ...
*September 2, 2015*

**Chemistry-HELPPPP! PLEASE **

During the operation of a bunsen burner, a chemical reaction occurs. This chemical reaction is represented by the chemical equation below: methane + oxygen - carbon dioxide +water. During this chemical reaction, methane and oxygen are converted into carbon dioxide and water. I...
*September 2, 2015*

**Chemistry**

why is graphing a useful way for scientists to display data?
*September 2, 2015*

**Chemistry**

Calculate the density of an unknown sample of metal given that a 2.3504 gram sample of metal causes the water level in a graduated cylinder to rise from 33.5 ml to 35.2 ml. Show work
*August 31, 2015*

**Precalc HELP!!!**

Are These Right?? I'm kinda suck on #30!!
*August 31, 2015*

**Precalc**

How do you know what quadrant these two are in? I'm having a little trouble determining. Can someone check if my answers are correct for all and help me fix it to make it right. 10.) The point is on the x-axis and 12 units to the left of the y-axis. My answer: (0, -12) 12...
*August 31, 2015*

**French**

For #1 I meant- Hier était le lundi . Oh yes, thankyou for catching that. Yes I'd like that in French too & you helped with that already. As far as everything else, are my accents right and the sentences are correct??
*August 31, 2015*

**math**

i am a 6-digit number greater than 700,000.my hundred thousands digit is twice my ones digit,my thousands digit,and my hundreds digit.my remaining digits are the same-a prime number greater than 5
*August 26, 2015*

**Algebra 2**

Matt got caught lmao
*August 26, 2015*

**Health**

What is the primary function of the skeletal muscle?. A. Contraction B. Heating the body C. Protecting the body from harm D. Pumping blood to the rest of the body
*August 20, 2015*

**Math**

Peter is 8 years younger than Alex. In 9 years' time, the sum of their ages will be 76. How old is alex now?
*August 8, 2015*

**math**

yes
*July 28, 2015*

**math**

There are ? different ways to represent the square root of 1000000 in the form a square root b, where a and b are positive integers. One way is 1 square root 1000000 A. 2 B. 4 C. 12 D. 16 About this question, i have no idea what they are trying to ask....
*July 28, 2015*

**math**

A baseball pitcher can throw a base ball at 150 ft/s. Can this pitcher hit the 200-ft ceiling of its game dome, if he was capable of giving a baseball an upward velocity of 85 ft/s, from a height of 7 ft? (Assume the ball is traveling as a free-falling body, and g = 32 ft/s2...
*July 19, 2015*

**Geometry**

A regular pentagon has side length 12cm.the perimeter of the pentagon is 60cm and the area is 247.7cm2 .a second. Pentagon has side lengths equal to 24cm .find the perimeter of the second pentagon
*July 14, 2015*

**Physics**

An air puck of mass 0.382 kg is tied to a string and allowed to revolve in a circle of radius 0.64 m on a horizontal, frictionless table. The other end of the string passes through a hole in the center of the table and a mass of 0.67 kg is tied to it. The suspended mass ...
*June 19, 2015*

**Chemistry**

If a 0.688 mole sample of silver at 19.6°C absorbs 1.162 kJ of heat, what is the final temperature in C?
*June 10, 2015*

**Language Arts**

Did you already take the quiz?
*June 5, 2015*

** Math**

Jesse and Leah can install a new gutter system on a house in 4 hours when they work together. Working alone, it would take Leah twice as long to install a new gutter system as it would take Jesse working by himself. Leah caught a really bad cold and called in sick this morning...
*May 26, 2015*

**Math **

A spy plane, whose average speed in still air is 250 mph, departs with a 40 mph tailwind and returns to the same airport flying into the same wind. How far from the airport can the plane fly if it has enough fuel to fly for 5 hours?
*May 26, 2015*

**math**

What a horribly vague answer Steve. To someone who had a similar problem, you were of no help. can you at least say what the letters/variables represent?
*May 4, 2015*

**maths**

Solve for one of the variables in one of the equations, then plug that into the other two equations and solve for the other two variables. The easiest was to do this is honestly using linear algebra and turning that into a augmented matrix, but i dont know if you have taken ...
*May 3, 2015*

**Chemistry(difficult)**

Thank you DrBob, you saved a couple hours of my life.
*May 3, 2015*

**Chemistry(difficult)**

A moon rock collected by a U.S. Apollo mission is estimated to be 3.70 billion years old by uranium/lead dating. Assuming that the rock did not contain any lead when it was formed, what is the current mass of 206Pb per 1.185 g of 238U in the rock? The half-life of 238U is t1/2...
*May 3, 2015*

**Math**

A solid is made up of two rectangular prisms how would I find the surface area of the solid? The diagram shows 3 feet on top, 6 feet on the left side, 7 feet on the bottom, 2 feet and 4 feet to the right Our teacher gave us the answer of 156 then told us to figure out how she ...
*April 28, 2015*

**geometry **

What will happen to the circumference and the area of the maze a fun house maze that is circular in shape has a diameter of 50 feet. the owner decides to double the radius of the maze?
*April 27, 2015*

**Math**

Thank You Ms. Sue - you have been a great help as always. Josh
*April 27, 2015*