Tuesday

August 4, 2015

August 4, 2015

Total # Posts: 4,090

**chem**

Radioactive substances decay by first-order kinetics. How many years would be required for a sample containing strontium-90 to decrease to 58.32% of its initial activity? The half-life of strontium-90 is 2.88e1 years.
*February 22, 2014*

**college chemistry**

awesome thanks!
*February 22, 2014*

**math**

given THE DERIVATIVE 8X^3+ 9X^2 -2X +5. find the original equation using (2,3)
*February 18, 2014*

**math**

The equation of a line is X+Y=1 and the equation of the function is y= 2/x +k. Solve for k and find the points on the tangent line
*February 18, 2014*

**sociol student**

A woman wantes to drive 83 km in 2 h. If she average 42 km/h for the first 1.27 h, what average velocity must she maintain for the remaining time in km/h?
*February 18, 2014*

**speech**

I have to do an explanatory speech. i have to choose a discovery or innovation that people know the general idea about but dont know anything beyond that. does anyone have any ideas? Just as an example of the type of speech im looking for you could do : Counterfeit money(and ...
*February 17, 2014*

**math**

This is just too SIMPLE!!1
*February 13, 2014*

**Math**

Half of a pizza was split evenly among 5 adults, two of whom split their share of the pizza into thirds with their children. What fraction of the pizza did the pizza did each of the children get?
*February 12, 2014*

**Math**

Ruth is making a quilt and needs 7/8 of a yard of fabric for each of the 5 fabrics in the quilt. How much total fabric does she need? Express your answer as a mixed number.
*February 12, 2014*

**Math**

Nathan has 3.5 bags of marbles in his room. The rest of the marbles are in his car. If he owns 6 bags of marbles, how many bags are in the car?
*February 12, 2014*

**MATH CHECK ANSWERS**

Good Job!
*February 11, 2014*

**Math**

Solve for y Xy+ p=5
*February 6, 2014*

**math**

How to do data, picture, equation and result for a problem
*February 3, 2014*

**Calculus & Vectors**

A search and rescue aircraft, travelling at a speed of 240 km/h starts out at a heading of N 20 degrees West. After travelling for 1h and 15 min, it turns to a heading of N 80 degrees E and continues for another two hours before returning to base. Find the total distance the ...
*February 1, 2014*

**physics**

A barge is hauled along a straight-line section of canal by two horses harnessed to tow ropes and walking along the tow paths on either side of the canal. Each horse pulls with a force of 450 N at an angle of 15° with the centerline of the canal. What is the net force on ...
*January 28, 2014*

**college physics**

Suppose a 200-kg motorcycle is heading toward a hill at a speed of 30.0 m/s. The two wheels are approximately annular rings with an inner radius of 28.0 cm and an outer radius of 33.0 cm. The mass of one wheel is 12 kg.What is the initial rotational kinetic energy
*January 28, 2014*

**physics**

Does an solid expand or contract as the temperature rises?
*January 28, 2014*

**physics**

1. Where does sound travel fastest? water, salt water, steel, or wood 2. Does sound travel faster in salt water than water?
*January 28, 2014*

**Calculus HELP!!**

The 6 2 1 is supposed to be on the right hand side of the equal sign. I am so sorry again!!!
*January 27, 2014*

**Calculus HELP!!**

Then after this, use that fact to find x1 and x2 that satisfies the equation: 6 2 6 4 2 2 5 3 {x1 and x2} = 1
*January 27, 2014*

**Calculus HELP!!**

u=6 4 5 v=2 2 3 w=6 2 1 show that 2u - 3v - w = 0 Sorry!! I hope this makes a bit more sense...Can we try to do this step by step so I can understand it better?
*January 27, 2014*

**Calculus HELP!!**

6 2 6 Let u = 4 , v = 2 , w = 2 5 3 1 Show that 2u - 3v - w = 0. Use that fact to find x1 and x2 that satisfy the equation 6 2 6 4 2 {x1} = 2 5 3 {x2} 1
*January 27, 2014*

**Science**

Melaine is tired all the time. No matter how much rest she gets and food she takes in she doesn't have energy. What is the organelle that is malfunctioning in her cells? Justify your answer.
*January 25, 2014*

**physics**

Water drips from a faucet into a flask at the rate of two drops every 3 seconds. A cubic centimeter contains 20 drops. What volume of water, in cubic decimeters will be collected in 1 hour?
*January 23, 2014*

**math help**

Round to nearest ten thousandth: 4.803621
*January 22, 2014*

**math help**

Round to nearest ten thousandth: 4.803621
*January 22, 2014*

**Science - 7th grade**

Is radiation damaging to the health of humans? If so, in what way/ways? My answer is: Yes, radiation though helpful in treating certain diseases is damaging to the health of human beings in many ways one of which being that it mutates our DNA and is unhealthy. It can also make...
*January 16, 2014*

**Ap world**

What caused feudalism to develop in japan? Europe? Can you please give the cause separately for each because I keep finding answers of them together. Thank you
*January 12, 2014*

**Social studies (History)**

Yes, those are great... Thank you...
*January 9, 2014*

**Math Question**

Hi, I need help with a math question. Thank you to whoever helps me! :) When solving a system of 2 equations and 2 unknowns using the substitution method, what is the ideal value of the coefficient of the isolated variable?
*January 7, 2014*

**Elementary Math**

I had her do an exact 15.4 x .7 and came up with 10.78. Just wanted to show her that this was the correct way of doing this problem. She didn't believe me :) Thanks for your help and confirmation
*January 2, 2014*

**Elementary Math**

This is going to seem like a simple question but how do i solve this without dividing.. 5th grade math mom Question: Lester's car can go 15.4 miles on 1 gallon of gas. How far can he go on 0.7 gallons? Thanks
*January 2, 2014*

**algebra**

Identifying Zeros and Their Multiplicities f(x) = 5(x - 2)(x + 3)²(x - 1/2)4
*January 2, 2014*

**chemistry**

Nitroglycerin, C3H5N3O9, is a shock sensitive liquid (density = 1.450 g/mL) that detonates by the reaction 4 C3H5N3O9(l) ® 10H2O(g) + O2(g) + 6N2(g) + 12CO2(g) How many grams of N2 will be produced during the detonation of 2.813 L of nitroglycerin?
*December 15, 2013*

**Spanish 2 Help!**

Fill in the blamks with the appropriate pronoun and conjugated reflexive verb. 1.)Tu_____ ______ el pelo (peinarse) Bank 1= Blank 2= 2.)Raul y Sarita no___ ___ afeitarse) Blank 1= Blank 2= 3.)No prefiero_____el pelo.(lavarse) Blank 1= 4.)Elena____ ____a las 10:00(acostarse) ...
*December 8, 2013*

**stats**

in a sample of 159,949 first year college students, the national survey of student engagement reported that 39% participated in community service or volunteer work.find the margin of error for 99% confidence. ...idk what formula to use.
*December 5, 2013*

**College algebra**

Solve the system Y=3x-2 6x-2y=30
*December 3, 2013*

**College algebra**

Solve the system X=2y+3 3x+4y=59
*December 3, 2013*

**calc**

thanks. so how would u see if f is undefined? how do you get f from f'?
*December 3, 2013*

**calc**

The derivative of a function f is f'(x) = x^2 - 8/x: Then at x = 2, f has A. an infection point B. a relative maximum C. a vertical tangent D. a discontinuity E. a relative minimum how do you test for all of these?
*December 3, 2013*

**calculus**

thanks! i forgot to add the 4 to the .5xy
*December 3, 2013*

**calculus**

A display case is in the shape of a rectangular box with a square base. Suppose the volume is 21 cubic ft and it costs $1 per square ft. to build the glass top and $0.50 per sq. ft. to build the sides and base. If x is the length of one side of the base, what value should x ...
*December 3, 2013*

**calc**

Find an equation for the tangent line to the curve x2y + xy3 = 2 at the point (1, 1).
*December 2, 2013*

**calc**

oh sorry i see now. thanks!
*December 2, 2013*

**calc**

x is suppose to be the number of trees planted per acre,
*December 2, 2013*

**calc**

the answer they give is y=240x -3x^2 and i have no idea how they got that because i did get the y=4500 +60x-3x^2 as my answer and that is a choice but its not the correct one.
*December 2, 2013*

**calc**

When 30 orange trees are planted per acre each tree yields 150 oranges For each additional tree per acre, the yield decreases by 3 oranges per tree. Express the total yield of oranges per acre, Y , as a function of the number of trees planted per acre, x, if x < or ...
*December 2, 2013*

**Algebra **

The length of a rectangle is more than double the width, and the area of the rectangle is . Find the dimensions of the rectangle.
*December 1, 2013*

**math for liberal arts**

construct a truth table to determine whether each argument is valid. Be sure to state whether it is valid or invalid with each question. 1) ~p v q p ____ triangle of dots p^~q
*November 30, 2013*

**Advanced Funtions**

Are there any angles x and y that satisfy sin(x+y)= sinx+siny? Use an example to explain your answer.
*November 19, 2013*

**Advanced Functions**

Determine an expression using trigonometric ratios of special angles that simplifies to an answer of sqrt3/2. Use three different angles.
*November 19, 2013*

**Advanced Functions**

x and y represent two angles in standard position. x has its terminal arm in the first quadrant and y has its terminal arm in the third quadrant. If cosx=5/13 and cosy = -5/13 then find the value of 2sinx+2siny+2cosx-2tanx+tany+2cosy
*November 19, 2013*

**physics**

What are the decibels 917m away from a 35.5 W sound source?
*November 19, 2013*

**art**

what type of lines do you see in the art piece Kerry James Marshall 1994?
*November 17, 2013*

**5th grade math parent**

Hi the problem reads.......give an example that shows how to use.the distributive property to multiply a number by a sum. All of the numbers you use should be mixed numbers or fractions.........PLEASE HELP!
*November 12, 2013*

**math**

The world population in 1992 is 5.42 billion. If its population doubled every 41 years, what would its population be in 41 years? 41 years, what would its population be in 82 years? 82 years, what would its population be in 164 years?
*November 11, 2013*

**bangladesh**

In the space before each of the following items, place a C if the capitalization is correct, a zero (0) if it is incorrect. Then insert capitals where they should be, and draw a line through capitals that should be small letters. 1. the Rocky Mountains 2. my spanish course 3. ...
*November 11, 2013*

**physics**

a heat engine operates between 403 K and 1263 K at 67% of Carnot efficiency. How much work can it produce from 5900J of input heat?
*November 6, 2013*

**Calculus-Aproximate Areas**

A ball is thrown upward at time t = 9 seconds on planet Ubuntu, and its acceleration from time t=9 seconds to t=21 seconds is given by the function . a(t) = (3) / (t - 8) m/s^2 Use 4 time intervals of equal length to overestimate, and then underestimate, the relative velocity ...
*November 6, 2013*

**econ**

Market demand facing a monopolist is Qd=-5P+20. If the monopoly practices perfect price discrimination, what is the profit-maximizing level of output when MC=$2?
*October 31, 2013*

**Calculus-concavity and graphing**

(2x+1)/(8x+1) f is increasing for x: f is decreasing for x: find local max/min:
*October 30, 2013*

**Calculus-Applied Optimization Problem: **

Find the point on the line 6x + 3y-3 =0 which is closest to the point (3,1). Note: Your answer should be a point in the xy-plane, and as such will be of the form (x-coordinate,y-coordinate)
*October 30, 2013*

**chemistry**

calculate the molar mass of a liquid if .955grams of its vapors occupy 2.50Liters at 200 Celsius and 45 torr
*October 30, 2013*

**Calculus Homework**

Find the largest region over which the function f is increasing or decreasing, for: f(x):(x-4)/(x+8) f is increasing for x=
*October 23, 2013*

**Calculus-Mean Value Theorem**

Find the function G(x) whose graph passes through (pi/38,-12)and has f(x) as its derivative: G(x)= I already found which is: F(x)=76(1/-19)cos(19x)+C
*October 23, 2013*

**Practice Exam Calculus**

f(x) = 6sqrt{x}- 9x n the interval [1,9]. f(c)=f(9)-f(1)/9-(1)=? Verify that the conclusion of the Mean Value Theorem holds by computing Now find,c in (1, 9) so that f'(c) equals the answer you just found. c=?
*October 22, 2013*

**Math**

378 squared feet - it could be wrong so i suggest you try working it out with someone besides me first.
*October 21, 2013*

**physics**

1.what is the final velocity of a hoop that rolls with out slipping down a 3.00m high hill starting at rest? 2. a 1.80 m radius playground merry go round (disk = 1/2 m r^2) hass a mass of 120 kg and is rotating with an angular velocity of .600 rev/s. what is the angular ...
*October 21, 2013*

**chem 1211**

P2 +3H2=2ph3 How many grams of ph3 can be formed when 37.5 grams of p2 and 83 L of h2 gas are reacted at 1 atm and 273.25 K? I really need a step by step of this problem. Thanks in advance!
*October 21, 2013*

**Chemistry**

Choose from the list the correct electron configurations for the following ions. A B C D E F G H I J K+ A B C D E F G H I J In+ A B C D E F G H I J Li+ A B C D E F G H I J Na+ A. 1s22s22p63s23p6 B. 1s22s22p63s23p64s23d104p64d105s25p1 C. 1s22s22p63s23p63d104s2 D. ...
*October 20, 2013*

**mathematics**

exmples of logarithms
*October 15, 2013*

**Physics-Help Please!**

a 25gram bullet is fired upward through a .36kg block. the block goes up 17cm in the air and the bullet goes up 24m into the air. What is the initial velocity of the bullet?
*October 12, 2013*

**physics**

a .025kg bullet is fired upward through a .36kg block. the block goes .17meters and the bullet goes up 24 m in the air. what is the initial velocity of the bullet?
*October 9, 2013*

**Chemistry**

During your experiment, you are drive water from the hydrate M x X y ⋅zH 2 O . You subsequently determine that your hydrate has four molecules of waters associated with each formula unit. However, the bottle the hydrate came from indicated a formula with only six ...
*October 8, 2013*

**maths**

A little late but here is the answer: You know that the rate of change of the volume is dV/dt = 2 (given in the question). You also know that V = x^3 + 25x To find the rate of change of the depth of the liquid, we find dx/dt = dx/dV x dV/dt dV/dx = 3x^2 + 25, so dx/dV is 1 ...
*October 3, 2013*

**Eng. Comp III**

I'm not sure what I am supposed to do here I am to write a Bibliographic essay on my sources for my final research essay - what does this entail? I don't want you to do my homework for me,just give me a couple of examples please, Thank You, Sara
*October 3, 2013*

**health HELP**

4. Which of theses provides the most Vitamin A? Vitamin B, Vitamin C, Vitamin D, Vitamin E, Vitamin K? Cheeseburger French fries, 10 strips Oatmeal cookie Cup of apple juice Cup of chocolate milk
*October 2, 2013*

**health HELP**

Which of theses items provide the most zinc? Cheeseburger French fries, 10 strips Oatmeal cookie Cup of apple juice Cup of chocolate milk
*October 2, 2013*

**math**

write each addiction vertically. decide which new groups you will make. then add to see if you were correct. 256+1.273 A new ten? A new hundred? A new thousand?
*October 1, 2013*

**music (Anyone)**

who knows 2 same pieces of music but have different performers?
*October 1, 2013*

**physics**

A shopper in a supermarket pushes a loaded cart with a horizontal force of 12 N. The cart has a mass of 33 kg. (a) How far will it move in 7.0 s, starting from rest? (Ignore friction.) m (b) How far will it move in 7.0 s if the shopper places her 30 N child in the cart before ...
*September 30, 2013*

**Math**

5th grade parent can you please show me how to break down 4 4/5 does it end up being 24/5? the probleam is: 4/4/5 -1 7/8
*September 30, 2013*

**math**

Thank you Jai!
*September 30, 2013*

**math**

5th grade math parent. This will sound dumb but.... 5/7 1/2 and 3/14. The sum is 1 3/7 correct? The question reads MArshall surveyed his classmates and found 5/7 have a sister, 1/2 have a brother, and 3/14 do not have siblings. The question is: Why does it make sense for the ...
*September 30, 2013*

**math**

5th grade math parent. This will sound dumb but.... 5/7 1/2 and 3/14. The sum is 1 3/7 correct? The question reads MArshall surveyed his classmates and found 5/7 have a sister, 1/2 have a brother, and 3/14 do not have siblings. The question is: Why does it make sense for the ...
*September 30, 2013*

**Physics**

A car traveling at a constant speed of 33.4 m/s passes a trooper hidden behind a billboard. One second later the trooper starts the car with a constant acceleration of 3.28 m/s2 How long after the trooper starts the chase does he overtake the speeding car
*September 25, 2013*

**Physics**

A car traveling at a constant speed of 33.4 m/s passes a trooper hidden behind a billboard. One second later the trooper starts the car with a constant acceleration of 3.28 m/s2 How long after the trooper starts the chase does he overtake the speeding car
*September 25, 2013*

**Physics**

A car traveling at a constant speed of 33.4 m/s passes a trooper hidden behind a billboard. One second later the trooper starts the car with a constant acceleration of 3.28 m/s2 How long after the trooper starts the chase does he overtake the speeding car
*September 25, 2013*

**Physics**

A car traveling at a constant speed of 33.4 m/s passes a trooper hidden behind a billboard. One second later the trooper starts the car with a constant acceleration of 3.28 m/s2 How long after the trooper starts the chase does he overtake the speeding car
*September 25, 2013*

**Physics**

A car traveling at a constant speed of 33.4 m/s passes a trooper hidden behind a billboard. One second later the trooper starts the car with a constant acceleration of 3.28 m/s2 How long after the trooper starts the chase does he overtake the speeding car
*September 25, 2013*

**Physics**

A car traveling at a constant speed of 33.4 m/s passes a trooper hidden behind a billboard. One second later the trooper starts the car with a constant acceleration of 3.28 m/s2 How long after the trooper starts the chase does he overtake the speeding car
*September 25, 2013*

**Physics**

a car travels at 25m/s on a flat stretch of road. The driver must maintaint he pressure on the accelerator to keep the care moving at this speed. What is the net work done on the car over a distance of 250m?
*September 25, 2013*

**Physics**

a car travels at 25m/s on a flat stretch of road. The driver must maintaint he pressure on the accelerator to keep the care moving at this speed. What is the net work done on the car over a distance of 250m?
*September 25, 2013*

**English**

Thanks again for your help.
*September 24, 2013*

**English**

Okay...
*September 24, 2013*

**English**

What does stilted mean?
*September 24, 2013*

**English**

I think that "and" shouldn't be added after fish.
*September 24, 2013*

**English**

How would you evaluate this writing piece in terms of writing, grammar, style and content?
*September 24, 2013*

**English**

Thankyou so much Writeacher! Please let me know if you see any other spelling or grammar errors.
*September 24, 2013*

**English**

This sentence needs to be paraphrased: This environmental concern should be addressed through legislative (law) changes, and enforcement to the Species at Risk Act, and the Environmental Protection and Clean Water Acts. There is alot of "and" used here.
*September 24, 2013*