Monday

May 25, 2015

May 25, 2015

Total # Posts: 249

**AP Chem ---**

Iron-59 has a half-life of 45.1 days. How old is an iron nail if the Fe-59 content is 25% that of a new iron sample? Please show the calculating so I can learn to do it.
*May 22, 2015*

**AP Chem ---**

Iron-59 has a half-life of 45.1 days. How old is an iron nail if the Fe-59 content is 25% that of a new sample of iron? Please show the calculating so I can learn to do it.
*May 22, 2015*

**AP Chem ---**

If a radioactive nucleus alpha decays to yield a sodium24 nucleus in 14.8 hours, what was the identity of the original nucleus? Nuclear equation?
*May 22, 2015*

**Chemistry **

AP Chem ---- Which type of radiation is emitted when chromium 51 decays into manganese 51? Show the nuclear equation that explains it.
*May 22, 2015*

**Chemistry **

AP Chem --- PbS + O2 = PbO + SO2 Balance the equation and write a short paragraph explaining the electron transfers that happen.
*May 22, 2015*

**Chemistry **

AP Chem - Which element is oxidized in the following reaction: CuO(s) + H2 (g) Cu(s) + H2O (l)
*May 22, 2015*

**Chemistry**

Which salt would result from the acid-base reaction of phosphoric acid and potassium hydroxide? I already know I will have to write and equation and it with make water (H2O) and a salt. I think it starts like this... H3Po4 + KOH = K2HPO4 + H2O But I'm not sure what to do ...
*May 22, 2015*

**chemistry**

the accepted density of helium at stp is 0.18 g/L. during an expirement, 0.10g of helium with a volume of 0.54L at stp was collected. what is the percent error in this expirement? (accepted-expiremental)/accepted X 100
*April 21, 2015*

**Calculus **

Let f(x)=(lnx)^4 f'(x)=4(ln(x))^3/x what is f'(e^2)=?
*April 6, 2015*

**Math**

For what values of a and b is the line 3x+y=b tangent to the curve y=ax^3 when x=–3?
*February 12, 2015*

**English skills with reading**

How do I know if a paragraph lacks transitional words? Or if the paragraph contains a fragment and a run-on?
*February 7, 2015*

**Chemisty**

Slaked lime (Ca(OH)2) is formed from quicklime (CaO) by the addition of water: CaO(s) + H2O(ℓ) → Ca(OH)2(s). What mass of slaked lime can be produced from a mixture of 29.8 g of CaO and 10.3 g of H2O? Answer in units of g.
*February 4, 2015*

**Chemisty**

For the reaction 3 Mg + N2 → Mg3N2 , what is the maximum amount of Mg3N2 which could be formed from 6.66 mol of Mg and 9.34 mol of N2? Answer in units of mol.
*February 4, 2015*

**chemistry**

A CHM 111 student recorded the mass of a piece of dry lead metal as 23.7412 g. He obtained a graduated cylinder and recorded an initial water volume of 25.0 mL; upon addition of the metal, the water level rose to 27.1 mL. Calculate the density of lead in units of g/mL. (Watch ...
*January 25, 2015*

**calculus**

Previously asked: the length of a rectangular prism is increasing at a rate of 8 cm/s, its width is increasing at a rate of 3 cm/s, and its height is increasing at a rate of 5 cm/s. when the length is 20 cm, width is 10 cm, and height is 15 cm, how fast is the volume of the ...
*December 7, 2014*

**calculus**

the length of a rectangular prism is increasing at a rate of 8 cm/s, its width is increasing at a rate of 3 cm/s, and its height is increasing at a rate of 5 cm/s. when the length is 20 cm, width is 10 cm, and height is 15 cm, how fast is the volume of the rectangular prism ...
*December 6, 2014*

**Math (IB Calc)**

A ferris wheel has a diameter of 50 meters. If point A is at the lowest point of the ferris wheel, 0 meters. What is the height of point A if the wheel moves 2pi/3 radians clockwise? What is the equation?
*November 20, 2014*

**Physics**

two forces one of 12n and another of 2n act on a body in such a way that they make an angle of 90 with each other.find the resultant of the two forces.
*November 9, 2014*

**Physics**

calculate the component of a force of 200n at a direction of 60 to the force.
*November 9, 2014*

**physics**

state which of the following are vectors and which are scalars distance, mass time, weight, volume ,density ,speed verbosity acceleration ,force,temperature and energy.
*November 8, 2014*

**science**

anyone
*October 22, 2014*

**science **

1. The process in which the chromosomes in sex cells are reproduced by half is called _____________. 2. A white mouse is crossed with a black mouse. all of the offspring were grey. The genes for fur color in mice show _________. 3. Genes are specific sections of __________. 13...
*October 22, 2014*

**science **

1) a pea plant with yellow seeds is crossed with a pea plant with green seeds. all of the offsprings have yellow seeds. the allele for yellow sees is a. Dominate because all offspring have yellow seeds. b. Recessive because all of the offsprings have yellow seeds. c. dominant ...
*October 21, 2014*

**algerbra**

Graph the inequality 3x + y ¡Ü 5 on a separate piece of paper. List in the answer box:
*June 13, 2014*

**Math **

How many minutes would it take Rachel to jog 3 miles if she jogs 1/15 mile every minute?
*May 15, 2014*

**Math**

Can you help answer thx
*May 15, 2014*

**Math**

John has 1/4 yard of fabric. He cuts it into 3 equal pieces . What fraction of a yard is each piece of fabric? Choices are A. 1/12 yard B, 1/8 yard C. 1/2 yard D. 3/4 yard please help answer
*May 15, 2014*

**history **

1) in what context was the crtc and its CanCom regulations established? Describe the rationale for thw creation of the crtc. I dont understand what it means by 'in what context' and how the two parts are different from one another and how to answer them differently.
*May 14, 2014*

**Math**

The formula for the velocity of an object is , where v is the velocity of the object, d is the distance traveled, and t is the time elapsed while that distance is traveled. v=d/t distance = speed times time so time in seconds = distance in meters / speed in meters/second we ...
*February 18, 2014*

**Physics**

An inclined plane is used to raise a 100 kg box to a height of 5 m. How long must the inclined plane be if a force of 250 N is used to push the box up the inclined plane?
*January 28, 2014*

**physics**

In one dimension ,how does energy depend on size of region if an electron is confined there ??
*December 23, 2013*

**Phisics**

A violin string vibrates at 298 Hz when unfingered. At what frequency will it vibrate if it is fingered one sixth of the way down from the end?
*November 27, 2013*

**Phisics**

An object with mass 2.0kg is attached to a spring with spring stiffness constant 240N/m and is executing simple harmonic motion. When the object is 2.2Ã—10âˆ’2m from its equilibrium position, it is moving with a speed of 0.65m/s . Calculate the ...
*November 27, 2013*

**physical**

Libby pulls a 3.9kg box to the right with a force of 200 n at a 45 degree angle relative to the horizontal along a frictionless surface. What is the acceleration of the box?
*November 5, 2013*

**humanties**

None of the above are true
*November 5, 2013*

**algebra**

What did the baby buzzard say when it say an orage in the nest
*October 6, 2013*

**Geometry**

Why don't you just follow the formula? V= pi r^2 h
*October 4, 2013*

**Maths**

The question is vague - I think it should have been, "How many more roses did A than B at first?" In this case, it's 14.
*October 4, 2013*

**6 grade math**

It is only adding 1 whole number to the fraction that make looks like improper fraction; say 1 1/4 = 5/4; adding 4/4 to 1/4. 4/4 is the fraction of 1 taken from the whole number 8 5/12 = 7 17/12 (added 12/12 to 5/12) 4 5/9 = 3 14/9 (added 9/9 to 5/9) 2 1/3 = 1 4/3 (added 3/3 ...
*October 3, 2013*

**science**

I think the first one is B. But I'm not for sure on that one. But the second one is output.
*September 19, 2013*

**Chemistry**

Although the VSEPR theory is correct in predicting that CH4 is tetrahedral, NH3 is trigonal pyramidal, and H2O is bent, the HNH angle in NH3 is only 107.3° and the HOH angle in H2O is only 104.5°. Explain these deviations from the expected tetrahedral angle of 109.5&...
*September 17, 2013*

**science**

Newton’s law of universal gravitation is rep- resented by F=GMm r2 Here F is the gravitational force, M and m are masses, and r is a length. Force has the SI units kg · m/s2. What are the SI units of the proportionality constant G? 1. m2/(kg2 · s2) 2. m/(kg...
*August 31, 2013*

**physics **

A plastic tube allows a flow of 14 cm3/s of water through it. How long will it take to fill a 240 cm3 bottle with water? Answer in units of s
*August 31, 2013*

**algebra**

Let U = {1, 2, 3, 4, 5, 6, 7}, A = {1, 2, 3, 4}, B = {1, 2, 5, 6}, and C = {3, 5, 7}. List all the members of the given set. (Enter your answers as a comma-separated list.)
*June 22, 2013*

**english**

revise the following sentences to eliminate shifts in tense, mood, voice or person. 7. The flight attendant said, "please turn off all electronic devices," but that we could use them again after takeoff. 8. The real estate market was was softer than it has been for a...
*May 19, 2013*

**math**

Oscar picked 12 apples. He gave 1/3 of the apples to Gil and 1/3 of the apples to Becky. How many apples did each of them?
*May 16, 2013*

**Science due tmrw**

Which simple machine does not change the direction of a force?
*March 27, 2013*

**Clueless in calculus**

Let f be the function be defined by f(x)=5^((2x^2)-1)^(1/2) A) is f an even or odd function? Justify answer. B) find the domain of f. C) find the range of f. D) find f'(x)
*March 14, 2013*

**Math Pre Cal **

Find the values of the trigonometric functions of è from the information given. cot è = 1/2 , sin è < 0
*March 7, 2013*

**physics**

How fast is a city on the earth's equator (such as Singapore) moving due to our planet's daily spin on its axis?
*February 23, 2013*

**Physics**

A test car travels in a straight line along the axis. The graph in the figure shows the car's position as a function of time
*February 22, 2013*

**Math**

if 3/5 of a group of children were girls, and there were 24 girls, how many children were in the group?
*January 30, 2013*

**Algebra 1**

Solve this proportion- 4/x+3=8/10
*January 24, 2013*

**Algebra 1**

Thank you, thank you, thank you, thank you!!!! I appreciate it very much! I worked on this for no lie, 30 minutes or so and could never get an answer that was one of the choices! Thank you soooooo much!
*January 24, 2013*

**Algebra 1**

A car travels on a highway at an average speed of 65 miles per hour. What was the speed in feet per second? (Remember- 1 mile=5280 feet)
*January 24, 2013*

**physics**

Solution of:An air plane ABC R=250m (x=30) the speed of the meachine is 450Km/h in A determine the accelartion supported by the pilot in A and the tangential accelartion is 10m.s determine the speed in B if the tangential accelaration is constant
*January 22, 2013*

**statistics**

1. 2.5
*January 14, 2013*

**Math (Algebra 1)**

Thank you for the explanation. I thought you maybe did everything on top and then divided the bottom number, but that didn't seem right. Thanks a lot though!! You were great help! :)
*November 8, 2012*

**Math (Algebra 1)**

I thought that was the answer, but I wasn't sure if I should do the division first because of order of operations?
*November 8, 2012*

**Math (Algebra 1)**

2y-z --------- for x=-3, y=13, z=5 x
*November 8, 2012*

**math**

thank you so much
*November 7, 2012*

**math**

The price of an oven changes from $450 to $396. (1 point)13.6% increase 13.6% decrease 12% increase 12% decrease
*November 7, 2012*

**physics**

A car of mass m = 1635 kg is pushed off a cliff of height h = 23 m. If the car lands a distance of 9 m from the base of the cliff, what was the kinetic energy of the car the instant after it left the cliff?
*September 28, 2012*

**Geometry**

@Steve The blue and yellow are part of the same earring.
*September 13, 2012*

**psychology**

multidirectional
*July 23, 2012*

**Physics**

Calculate the velocity of a satellite moving in a stable circular orbit about the Earth at a height of 2600 km.
*July 8, 2012*

**math**

a 15 ft ladder is palced against a wall such that its base is 9 ft away from the wall. if the base of the ladder is moved to 6 ft away from the wall, by about how much will the top of the ladder move up the wall?
*June 18, 2012*

**science**

what would be the complementary strand of DNA be for the following sequence of bases? C T T A G G C T T A C C A I'm stuck please help! my guess was ATTGCCATTGCCA
*April 25, 2012*

**algerbra**

Donna deposits into an account that pays simple interest at a rate of 5% per year. How much interest will she be paid in the first 6 years?
*April 23, 2012*

**Physics**

Find the force of tension in the chain. Determine the force of compression in the support bar. Be sure to include a free body diagram as part of your solution. Now the only information given is a mass=20.4 kg and the angle 22 degrees. If anyone could help me with this question...
*March 13, 2012*

**Physics- grade 12**

A ramp leading up to a loading platform is 3 m long and 1 m high at its highest point. If the friction is ignored, what work is needed to slide a 600-kg crate up the ramp at a constant speed? a) 2.00 *10^2 J b) 5.89 *10^2 J c) 1.80 *10^3 J d) 5.88 *10^3 J I believe the answer ...
*March 13, 2012*

**Physics**

In this problem they show a diagram of a pulley system with an inclined plane (25 degree incline). There is a box called m1=47kg resting on the incline plane and m1=35kg hanging on the vertical line. The question reads: The coefficient of friction between m1 and the surfvace ...
*March 13, 2012*

**Physics - grade12**

for some reason by multiplying the answer that I got for the "mass added" by 35kg, this gave me the answer at the back of the book
*March 13, 2012*

**Chemistry - Mole Ratio**

How many moles of oxygen are produced from the decomposition of 3.4g of hydrogen peroxide? How many molecules of O2 are produced?
*February 15, 2012*

**math**

thanks
*February 15, 2012*

**math**

is this not always true? because the square of 0.5 is 0.25 and that is less than the number, but the square of 3 is 9 which is greater than 3.
*February 15, 2012*

**math**

please help! is the square of a number greater than the number?
*February 15, 2012*

**math**

thanks so much ! have a blessed day/night
*January 31, 2012*

**math**

Those are the answer choices
*January 31, 2012*

**math**

A) r +.20 B) r + .15 C).15r D) 3R + .15
*January 31, 2012*

**math**

or each month jack works he earns an increase or raise of $. 05 on his hourly pay if he has already worked for three months, which shows his 4th month's hourly rate in terms of his first month's hourly rate?
*January 31, 2012*

**Algebra**

A weekly order is 10 gallons of coke to 15 gallons of 7up. What is the ratio of 7up to coke?
*January 17, 2012*

**Algebra **

A road map uses a scale of 3 cm for every 5 miles. How many miles are there in 9.5 cm?
*January 17, 2012*

**Chemistry**

What is the volume of a scuba tank if it takes 2000 L of air collected at 1.00 atm to fill the tank to a pressure of 150 atm? T is constant.
*December 9, 2011*

**Chemistry**

A hot-air balloon has a volume of 4.000 x 10^5 L at 30 degrees celsius and a pressure of 748 mmHg. If the average molar mass of air is 29.0 g/mol, what is the mass of air in the balloon?
*December 9, 2011*

**Chemistry**

Apply the gas laws to determine how many grams of sodium azide (NaN3) are needed to fill the air bag of your vehicle to a volume of 79.0 L at 35.0 degrees celsius and 1.00 atm. The reaction occurring in the air bag can be repesented by the equation, 2NaN3 (s)-> 2Na (s) + 3 ...
*December 9, 2011*

**Chemistry**

The combustion of methane can be described by the equation: CH4 (g) + 2 O2 (g) -> CO2 (g) +2H20 (g) If 22.0 mL of CO2 (g) were collected, what volume of H20 (g) also could be collected under the same conditions?
*December 9, 2011*

**Chemistry**

a helium balloon is partially filled with 28.7 L of gas at 25.0 degress celcius and a pressure of 1 atm. if the balloon is released and it floats up intp the atmosphere to a heightwhere the pressure is 2.8 x 10^-3 atm and the temperature is -24.0 degrees celcius, calculate the...
*December 8, 2011*

**math**

its 20 by 30
*November 16, 2011*

**math**

80 goldfish and it doesn't say how deep the aquarium it just says its a 20X30 square inch rectangular aquarium
*November 16, 2011*

**math**

what is the population density if your goldfish population was found in 20x30 sq inch rectangular aquarium?
*November 16, 2011*

**chemistry**

Predict whether nitrate salt solutions containing metal ions with the following outer shell electron configurations will be colored or colorless: [Ar] 3d^2 and [Kr] 4d^10
*November 7, 2011*

**trig**

write a product of two trig functions that equals 1.
*November 6, 2011*

**Chemistry**

Potassium, K, is more reactive than sodium, Na. Calcium, Ca, is less reactive than sodium. The comparative reactivity of these metals is often noted as: K > Na > Ca. Explain the reactivity differences of K, Na, Ca.
*October 31, 2011*

**statistics**

The profit for a new product is given by Z = 2X - 2Y - 7. We know that X and Y are independent random variables with Var(X) = 2 and Var(Y) = 2.7. What is the variance of Z?
*October 24, 2011*

**math**

Is 1 greater than or less than negative 1?
*October 23, 2011*

**chemistry**

the activity series of metals is: Au < Ag < Cu < Sn < Cd < Zn < Al < Mg < Na < Cs which reaction below occutrs spontaneously upong mixing the reageant shown? a) Sn(s) + Al3+ (aq)-> sn2+(aq) + al(s) b) sn(s) + zn 2+ (aq) -> sn 2+ (aq) +zn (s) c...
*October 23, 2011*

**Chemistry**

Thank you!
*October 20, 2011*

**Chemistry**

You observe that when copper is added to a soltion containing gold ions, the copper dissolves and the gold precipitates. Similarly, almost every other metal will displace gold from solutions of gold salts. a) Do these observations mean that gold ion is a unusally good ...
*October 20, 2011*

**Science **

Unrelated species may come to resemble one another over many generations due to
*October 6, 2011*