Saturday

December 10, 2016
Total # Posts: 4,395

**Chemistry**

If a sample of gas is cooled at a constant pressure until it shrinks to one-fourth its initial volume, what change in its kelvin temperature must have occurred?

*January 13, 2013*

**Algebra**

Nadia has 32 coins made up of nickles, dimes, and quarters. The sum of the number of nickels and the number of quarters is three times the number of dimes. If the total value of the coins is $4.60, how many of each kind does she have? I can't figure out how to make this ...

*January 13, 2013*

**Algebra**

Nadia has 32 coins made up of nickles, dimes, and quarters. The sum of the number of nickels and the number of quarters is three times the number of dimes. If the total value of the coins is $4.60, how many of each kind does she have? I can't figure out how to make this ...

*January 13, 2013*

**Algebra**

Nadia has 32 coins made up of nickles, dimes, and quarters. The sum of the number of nickels and the number of quarters is three times the number of dimes. If the total value of the coins is $4.60, how many of each kind does she have? I can't figure out how to make this ...

*January 13, 2013*

**Algebra**

Nadia has 32 coins made up of nickles, dimes, and quarters. The sum of the number of nickels and the number of quarters is three times the number of dimes. If the total value of the coins is $4.60, how many of each kind does she have? I can't figure out how to make this ...

*January 13, 2013*

**Math**

Name the lengths of the sides of three rectangles with a perimeter of 12 units. Use only whole numbers

*January 9, 2013*

**Physical science**

Compute the gravitational force between two 1.00 kg lead spheres whose centers are 1.00 m apart?

*January 6, 2013*

**physics**

Ceres is a dwarf planet located in the asteroid belt between the orbits of mars and Jupiter. the radius of Ceres is 4.76 x 10^5 m. suppose an astronauts stands on the surface of Ceres and drops a 0.85 kg hammer from a height of 1.25 m. the hammer takes 3.0 to reach the ground...

*January 5, 2013*

**Algebra**

8s+ 12 = 16, 6s+ 9t = 12 solve by substitution

*December 8, 2012*

**French**

1. J'utilise un ventilateur quand il fait chaud. 2. Je n'utilise pas le congélateur si j'ai froid. 3. Il ya une couverture sur mon lit. 4. Mes livres sont sur l'étagère. 5. Je mets mes vêtements dans l'armoire. 6. ...

*December 4, 2012*

**French**

1. J'utilise un ventilateur quand il fait chaud. 2. Je n'utilise pas le congélateur si j'ai froid. 3. Il ya une couverture sur mon lit. 4. Mes livres sont sur l'étagère. 5. Je mets mes vêtements dans l'armoire. 6. ...

*December 4, 2012*

**science**

Fast help Please Hurry!!!!!!!!!!!!!!!!!!!!!! A bicyclist is in a 50-km race. He says he had an average velocity of 35. What is missing in the cyclist’s velocity? A. units only B. units and distance C. direction only D. units and direction

*December 3, 2012*

**science**

Thanks so much!

*December 3, 2012*

**science**

im blank today please help thanks!!!!!!!!!!! It takes a car 1.75 h to go from mile marker 10 to mile marker 115. What is the average speed of the car? A. 1.6 mph B. 60 mph C. 65 mph D. 183 mph

*December 3, 2012*

**Algebra2**

Check? Give the slope and y-intercept of the given line. 1. 2x-3y=6 = 3y = 2x-6 y = 2/3 x - 2 2. y=-2x = 2/1x + 1 3. y=3 = y=3/1x + 3 3y = 2x-6 y = 2/3 x - 2

*November 29, 2012*

**Algebra2**

Check? Give the slope and y-intercept of the given line. 1. 2x-3y=6 = 3y = 2x-6 y = 2/3 x - 2 2. y=-2x = 2/1x + 1 3. y=3 = y=3/1x + 3 3y = 2x-6 y = 2/3 x - 2

*November 29, 2012*

**Algebra2**

Graph the given function using the given values of x. 1. f(x) = 5 ; x = -3, -2, -1, 0, 1, 2, 3 2. g(x) = x^3 + 2 ; x = -2, -1, 0, 1, 2

*November 29, 2012*

**math **

What's the inequality ? the crowd that heard the President speak was estimated to be 10000 people.The actual crowd could be 750 people more or less than this. what are the possible values for the actual crowd size?

*November 27, 2012*

**Math .-.**

All eighth grade students can choose to take one of the following elective courses: art, chorus, band, or woodworking. There are 2o more students enrolled in chorus than art. Band has 3/4 the enrollment as chorus. woodworking has 5 fewer students than band. Which expressions ...

*November 26, 2012*

**Chemistry**

.006

*November 21, 2012*

**Chemistry**

Calculate pH of NH4OH which is 1%ionized

*November 20, 2012*

**Grammar**

which one should be capitalized? (the Rocky Mountains)

*November 19, 2012*

**7th grade math Ms. Sue please**

(1 pt) Max’s percent increase was about 1.1% more than Sara’s.

*November 19, 2012*

**physics **

Calculate the net charge on a substance consisting of a combination of 8.9 × 10 13 protons and 2.6×10 13 electrons. The elemental charge is 1.6 × 10 −19 C. Answer in units of C

*November 18, 2012*

**Science**

How can knowing about the chemical properties of different elements help a society become more sustainable?

*November 14, 2012*

**Statistics**

$50.50+-11.08$

*November 14, 2012*

**chemistry**

assuming the reaction goes to completion, determine the final concentration of NH4Cl in the calorimeter. NH4Cl(s)+ H2O(l)-> NH4Cl(aq) concentration of NH4Cl is 1.00M its specific heat is 3.93 and density is g/ml. note: the exact same question was asked for a previous ...

*November 13, 2012*

**physics**

A ball is thrown horizontally off the top of a 65 m tall building at a velocity of 7.8 m/s. How far did the ball land from the base of the building? Round your answer to 2 decimal places.

*November 11, 2012*

**physics**

A ball is thrown horizontally off the top of a 65 m tall building at a velocity of 7.8 m/s. How far did the ball land from the base of the building? Round your answer to 2 decimal places.

*November 11, 2012*

**physics**

A rifle allowed a bullet fired with an initial horizontal velocity to travel 76.0 m while only falling a distance of 0.40 m. What was the initial x-velocity of the bullet? Round your answer to 2 decimal places.

*November 11, 2012*

**math**

sally made 12 dozen cookies .she sold 3 1/3 and gave away 2 3/4 how many are left

*November 7, 2012*

**Statistics**

A random sample of 14 evenings at the O'Sullivan house hold showed that the family received an average of 2.4 solicitation calls each evening. The sample standard deviation was s= 0.9. Find a 99% confidence interval for the population mean number of solicitation calls this...

*November 7, 2012*

**Chemistry**

1.63E-27 photon/sec

*November 5, 2012*

**Chemistry**

Calculate the mass of CO2 emitted (in lbs) when 1 gallon of octane is burned

*November 4, 2012*

**algebra**

If $1000 is invested in an account that earns 11.75%, compounded annually, what will the account balance be after 12 years?

*November 4, 2012*

**physics**

its includes 1. about any diameter 2. about a tangent in its plane 3. about a tangent perpendicular to its plane

*November 1, 2012*

**physics**

moment of inertia of a ring perpendicular to tangent and its plane

*November 1, 2012*

**Physics **

a refree throws a basketball vertically upward with an inital speed of 5.0m/s determine the maxium height above the floor reached by the basketball if it starts from a height of 1.50m

*October 28, 2012*

**Physics **

a refree throws a basketball vertically upward with an inital speed of 5.0m/s determine the maxium height above the floor reached by the basketball if it starts from a height of 1.50m

*October 28, 2012*

**Physics**

Thanks!!

*October 27, 2012*

**Physics**

A car of mass 1100 kg starts from rest at sea level and climbs a hill of altitude 50 m. At the top of the hill the car has a speed of 25 m/s. From the top of the hill the driver turns off the engine and coasts down to an altitude of 15 m. Assume the friction and the air ...

*October 27, 2012*

**Physics**

A car of mass 1100 kg starts from rest at sea level and climbs a hill of altitude 50 m. At the top of the hill the car has a speed of 25 m/s. From the top of the hill the driver turns off the engine and coasts down to an altitude of 15 m. Assume the friction and the air ...

*October 26, 2012*

**Physics**

A car of mass 1100 kg starts from rest at sea level and climbs a hill of altitude 50 m. At the top of the hill the car has a speed of 25 m/s. From the top of the hill the driver turns off the engine and coasts down to an altitude of 15 m. Assume the friction and the air ...

*October 25, 2012*

**calculus**

A street light is mounted at the top of a 6-meter-tall pole. A man 2 m tall walks away from the pole with a speed of 1.4 m/s along a straight path. How fast is the tip of his shadow moving when he is 16 m from the pole?

*October 16, 2012*

**college orgo**

calculate how to make 10 mL of 15:85 ethyl acetate:hexane solution from 2 mL of 5:95 ethyl acetate:hexane, using pure hexane and pure ethyl acetate.

*October 15, 2012*

**Physics**

Never mind, figured it out.

*October 14, 2012*

**Physics**

A wagon is rolling forward on level ground. Friction is negligible. The person sitting in the wagon is holding a rock. The total mass of the wagon, rider, and rock is 97.0 kg. The mass of the rock is 0.320 kg. Initially the wagon is rolling forward at a speed of 0.540 m/s. ...

*October 14, 2012*

**Physics**

87 09 7

*October 9, 2012*

**science**

I dissolved two different white solids into water. One solid dissolved and gave off heat and the other became cold. Reading various texts online, I was not sure if these were physical or chemical changes. Some texts say if these solids are salts then these are physical changes...

*October 8, 2012*

**physics**

A jogger runs down the street at a rate of 1.1 m/s. She sees the finish line, and speeds up to a velocity of 3.6 m/s over 1.1 s. What is the acceleration of the jogger?

*October 3, 2012*

**physics**

A ball is dropped from a height of 18.6 m. What is the velocity of the ball the instant it hits the ground?

*October 3, 2012*

**Math does anyone know this?**

I have to state whether these equations are parallel or perpendicular y=4x+6 y-4x=-1

*October 3, 2012*

**physics**

Sarah shoots a toy dart vertically downward at 11.7 m/s at Mark standing on the ground below. Calculate the dart's velocity after 0.8 seconds.

*September 30, 2012*

**physics**

Sarah shoots a toy dart vertically downward at 11.7 m/s at Mark standing on the ground below. Calculate the dart's velocity after 0.8 seconds.

*September 30, 2012*

**bridge to terabitha**

Hello i read the book bridge to terabitha and i have an assignment i need some help on. i need to pick 5 characters and describe six events or circumstances that caused the character to change or evolve. i have picked the characters Jesse Oliver Aarons Leslie Burke Mrs. Aarons...

*September 30, 2012*

**math**

how do u multiply a positive number and a negitave number

*September 26, 2012*

**science**

Draw the condensed structures of the esters formed from the following reactants. Name the compound in each case. (a) butanoic acid and methanol

*September 25, 2012*

**math**

There are 5 purple, 3 yellow, and 4 pink rocks in a jar. What is the chance of getting a purple rock if it was pulled out of the jar without looking?

*September 25, 2012*

**chem**

Using condensed structural formulas, write a balanced chemical equation for each of the following reactions a)addition of H2O to trans-2-pentene using H2SO4 as a catalyst (two products) i got 2-pentanol and 3-pentanol but it is counting it wrong!

*September 25, 2012*

**Chemistry**

A 2.914 gram sample of gypsum, a hydrated salt of calcium sulfat, CaSO4, is heated at a temperature greater than 170 degrees Celcius in a crucible until a constant mass is reached. The mass of the anhydrous CaSO4 salt is 2.304 grams. Calculate the percent by mass of water in ...

*September 24, 2012*

**math help?**

2x+4 (2x+6) I did this and ended up with a decimal number. I distributed then combined like terms.

*September 21, 2012*

**chemistry**

The atomic mass of chlorine is listed as 35.454 amu on the periodic table. It has two naturally occurring isotopes, CI-35 and CI-37. What are the approximate percentage of each?

*September 20, 2012*

**PHYSICS**

Suppose a moose jumps straight up with an initial upward velocity of 95 m/s. How long until the ungulate lands back on the ground, where it belongs?

*September 17, 2012*

**PHYSICS**

If a DeLorean rolls gently (vo = 0) off a vertical cliff, how long does it take it to reach a downward velocity of 78 km/h?

*September 17, 2012*

**physics**

Suppose a moose jumps straight up with an initial upward velocity of 95 m/s. How long until the ungulate lands back on the ground, where it belongs?

*September 17, 2012*

**physics**

Cubs outfielder Alfonso Soriano catches a ball 5.2 s after throwing it vertically upward. How high did the ball go, relative to his hand?

*September 17, 2012*

**physics**

A falling iPad takes 0.16 s to travel past a window 2.1 m tall. From what height above the top of the window did the mobile device fall?

*September 17, 2012*

**physics**

If a DeLorean rolls gently (vo = 0) off a vertical cliff, how long does it take it to reach a downward velocity of 78 km/h?

*September 17, 2012*

**physics**

A sophomore chemistry student holds a 500mL Erlenmeyer flask full of concentrated nitric acid high above his head at a height of 1.75 meters and declares, "I'm the King of Chemistry!" At that moment another student, startled by the sudden ignition of her Bunsen ...

*September 17, 2012*

**botany**

what is the difference between primary walls and secondary walls in plants. (specifically sclerencyma cells- which have secondary and parenchyma and collenchyma - which just have primary walls

*September 16, 2012*

**chem**

Draw the three distinct geometric isomers of 2,4-hexadiene. i can draw what it is giving. but i do not get what the geometric isomers are? if you drew it a different way wouldnt that change the name?

*September 15, 2012*

**Algebra..**

Help? If f = (1, 2), (2, 3), (3, 4), (4, 5), g = (1, -2), (3, -3), (5, -5), and h = (1, 0), (2, 1), (3, 2), 1. f+g 2. f-g 3. f*g

*September 14, 2012*

**Algebra..**

f(x)= x^2+3 ; g(x)=3x-1 Check These Please? 1.(fg)(-1) = 5 2. (f o g)(1) =10 How would you solve this? 1. (g o f)(x)

*September 14, 2012*

**physics**

A ping pong ball is rolling across a table at 2.1 cm/s. When the ball is 1.32 m away from the edge your little brother starts to blow on it. If the little doofus hopes to prevent the ball from falling off the edge, what minimum acceleration must be achieved?

*September 13, 2012*

**PHYSICS**

A Cessna 350 must reach a speed of 35 m/s for takeoff. If the plane accelerates at a steady 3.8 m/s2, how long must the runway be?

*September 13, 2012*

**PHYSICS**

When moving at highway speed, a Triumph America motorcycle is capable of accelerating at 2.1 m/s2. At this rate, how long does it take to accelerate from 103 km/h to 88 km/h?

*September 12, 2012*

**PHYSICS**

A ping pong ball is rolling across a table at 2.1 cm/s. When the ball is 1.32 m away from the edge your little brother starts to blow on it. If the little doofus hopes to prevent the ball from falling off the edge, what minimum acceleration must be achieved?

*September 12, 2012*

**chem**

Cobalt-60, which undergoes beta decay, has a half-life of 5.26 yr. (a) How many beta particles are emitted in 47.0 s by a 2.39-mg sample of 60Co? i got 2.44e19 but thast wrong

*September 12, 2012*

**physics**

When moving at highway speed, a Triumph America motorcycle is capable of accelerating at 2.1 m/s2. At this rate, how long does it take to accelerate from 103 km/h to 88 km/h?

*September 12, 2012*

**physics**

The minivan your mom lets you drive accelerates from 12 m/s to 24 m/s in 6.5 s. How far does it travel in this time? Assume constant acceleration.

*September 12, 2012*

**chem please help!**

The average energy released in the fission of a single uranium-235 nucleus is about 3. 10-11 J. If the conversion of this energy to electricity in a nuclear power plant is 45% efficient, what mass of uranium-235 undergoes fission in a year in a plant that produces 2000 megawatts

*September 11, 2012*

**Algebra..**

Help? If f = (1, 2), (2, 3), (3, 4), (4, 5), g = (1, -2), (3, -3), (5, -5), and h = (1, 0), (2, 1), (3, 2), Find and state the domain. 1. f+g 2. f-g 3.f*g

*September 11, 2012*

**pre algebra**

show the work for 136.8 divided by 3600

*September 10, 2012*

**Physics**

A baseball batter hits a long fly ball that rises to a height of 49 m. An outfielder on the opposing team can run at 7.7 m/s. What is the farthest the fielder can be from where the ball will land so that it is possible for him to catch the ball?

*September 10, 2012*

**chem**

A 73-kg person is accidentally exposed for 215 s to a 16-mCi source of beta radiation coming from a sample of 14C. What is the activity of the radiation source in disintegrations per second? In becquerels? i am not sure if there is an equation for this or wut??

*September 10, 2012*

**chem**

do you know how to do it using the numbers. I know for some problems uneeded information can be added but usually if its more than 2 peices then you use at least one of them

*September 10, 2012*

**chem**

it said that answers were wrong im pretty sure i have to use the 73 kg and 215 seconds.. or why would they put that in the question?

*September 10, 2012*

**chem**

I am not sure if there is an equation for this problem or wut?? A 73-kg person is accidentally exposed for 215 s to a 16-mCi source of beta radiation coming from a sample of 14C. What is the activity of the radiation source in disintegrations per second? In becquerels? (1 Ci...

*September 10, 2012*

**algebra**

art's age is two thirds cal's age, and bob is three years older than art. the sum of their three ages is 45. find the age of each one

*September 8, 2012*

**Physics**

A swimmer heads directly across a river, swimming at 1.10 m/s relative to the water. She arrives at a point 60.0 m downstream from the point directly across the river, 80.0 m wide. What is the speed of the river current? What is the swimmer's speed relative to the shore? ...

*September 6, 2012*

**math**

Two bulldozers clear homes from a 20-acre tract of land. One works twice as fast as the other. It takes them three days to clear the tract working together. How long would it take each of them alone? whats the equation?

*September 6, 2012*

**chemistry help!!**

I entered the asnwer I got and it is wrong.

*September 5, 2012*

**chemistry help!!**

thanks! so k=1.669e-11 so ln(65.3/45.9)=1.669e-11(t) so does t=2.112e10 years?

*September 5, 2012*

**chemistry help!!**

The half-life for the process 238U 206Pb is 4.5 109 yr. A mineral sample contains 45.9 mg of 238U and 16.8 mg of 206Pb. What is the age of the mineral? i used the equation: n(T)=n(O)/2^(t/halflife) and i got 6.53e9 but it is wrong. what am i doing wrong?

*September 5, 2012*

**math**

It just intersects at the point (0, -7), right?

*September 5, 2012*

**math**

So does this polynomial, when graphed, intersect the x-axis or it just comes close?

*September 5, 2012*

**math**

how many real roots does the polynomial 2x^5+8x-7 have

*September 5, 2012*

**statistics**

Thanks for the guidance. Does it make sense that I would get 1? 1. z = (x - μ) / σ z = (84-100)/8 z = -16/8 z = -2 and z = (116-100)/8 z = 16/8 z = 2 area = .0228+.9772 Area = 1

*September 4, 2012*

**statistics**

The mean of a normal probability distribution is 100 and the standard deviation is 8. About what percent of the observations lie between 84 and 116?

*September 4, 2012*

**Discrete Mathematics**

Mathematical sequences can be used to model real life applications. Suppose you want to construct a movie theater in your town. The number of seats in each row can be modeled by the formula C_n = 16 + 4n, when n refers to the nth row, and you need 50 rows of seats. (a) Write ...

*September 4, 2012*