Thursday

July 2, 2015

July 2, 2015

Total # Posts: 1,765

**Math**

Mr.Quakers science class has a 16 gallon aquarium that is 3/5 full. How much water is needed to fill it?
*March 8, 2013*

**Business Statistics**

1. Suppose that the mean of the annual return for common stocks from 1950 to 2012 was 9.4%, and the standard deviation of the annual return was 17.5%. Suppose also that during the same 62-year time span, the mean of the annual return for long-term government bonds ...
*March 6, 2013*

**Chemistry**

Ammonia is used as a fertilizer throughout the world. It is often produced by reacting nitrogen gas with hydrogen gas in a synthesis reaction. How much ammonia in grams can be produced from 9207 grams of nitrogen and 44 000 L of hydrogen?
*March 4, 2013*

**Chemistry**

Answer had to be expressed as just as an isotope so it is **108/48Cd DrBob222 Can you explain how you got the 48 though? Where did the other proton come in when you just added to the mass?
*March 1, 2013*

**Chemistry**

I was thinking of something like this? (I'm not sure how to approach this problem): 108/47Ag ---> 107/47Ag + 1/0n then, 108/46Pd ---> 108/47Ag + 0/-1e
*March 1, 2013*

**Chemistry**

When silver-107 is bombarded with a neutron, a different isotope of silver forms and then undergoes beta decay. What is the final product? (My Hints: Write two separate nuclear equations.)
*March 1, 2013*

**Chemistry**

**241/95Am ----> 237/93Np + 4/2He Is the correct answer indeed. I was confused about the part where it was just talking about subatomic particles and thought I wasn't adding an element to balance the equation but neutrons. Thank you!
*March 1, 2013*

**Chemistry**

There are several technological applications for the transuranium elements (Z > 92). An important one is in smoke detectors, which can use the decay of a tiny amount of americium-241 to neptunium-237.What subatomic particle is emitted from that decay process? Write a ...
*March 1, 2013*

**Chemistry**

75.7 days
*March 1, 2013*

**Chemistry**

Radium-223 has a half-life of 11.4 days.Approximately how long would it take for the activity of a sample of Radium-223 to decrease to 1.00% of its initial value?
*March 1, 2013*

**Pre-Calculus**

The stopping distance D of a car after the brakes have been applied varies directly as the square of the speed s. A certain car traveling at 70 mi/h can stop in 343 ft. What is the maximum speed it can be traveling if it needs to stop in 160 ft?
*February 26, 2013*

**college physics**

You are in the lab with a 10 V battery. You have a 10 W light bulb and you want to put 0.75 A of current through the light bulb and 7.5 V across the light bulb. This will allow the light bulb to have a brightness proportional to 5.625 W. Assuming any resistors that you need, ...
*February 26, 2013*

**Math**

Denna bought a bag of jelly beans. 1/3 are pink and 1/6 are blue. The rest are green. How many are green?
*February 25, 2013*

**Physics**

A thundercloud has an electric charge of 43.2 C near the top of the cloud and -38.7 C near the bottom of the cloud. The magnitude of the electric force between these two charges is 3.95 x 106 N. What is the average separation between these charges? (kc = 8.99 ×109 N &#...
*February 20, 2013*

**math**

gfrtyyngjtfghdyhjhv ndfhd,bbgrtf
*February 18, 2013*

**Math**

If the product of four tenths and six tenths is subtracted from the sum of four tenths and six tenths, what is the difference?
*January 30, 2013*

**math 121 **

jennifer is asked to complete 5 of the 7 essay questions on her literature exam how many choices does jennifer have?
*January 28, 2013*

**Engineering Math**

sorry didn't mean to lol but it is lol
*January 28, 2013*

**Engineering Math**

lol
*January 28, 2013*

**physics**

Suppose a 28.5 kg object is moving at 38.4 m/s along the x-axis just before it strikes a stationary 13.0 kg object. After the collision, the 28.5 kg object is moving with a velocity of 20.0 m/s at an angle of 5.79 degrees relative to the x-axis. What is the magnitude of the ...
*January 25, 2013*

**Chemistry**

What is the density, in grams per liter, of N subscript 2 gas at STP
*January 24, 2013*

**General math **

7t-6=104
*January 24, 2013*

**mt450**

need to focus on the main critical elements of simulation
*January 22, 2013*

**mt450**

Now that you have turned in your Simulation Final Project paper, the next step is to turn in your PowerPoint presentation of it. In the workplace, presentations like this play a key part in conveying marketing plans. Presentation requirements: • A minimum of 8 slides and ...
*January 22, 2013*

**Algebra**

Thanks. I figuired out the working, but not sure how to use the Let statement. Would it be correct to say Let A = original scholarship amount A = 1-1/3 -1/4-1/4 x72,000 A = 1/6 x 72 = 432,000
*January 10, 2013*

**Algebra**

Mary, Margaret, Ron and Nick are to share a sholarship. Ron receives 1/3 of the scholarship; Nick gets 1/4 of the scholarship; Mary receives the same as Nick, and Margaret receives $72,000. Find each person's share in the scholarship as well as the original scholarship ...
*January 10, 2013*

**literature**

In "Life without Principle," Thoreau writes, "If my wants should be much increased, the labor required to supply them would become a drudgery." What does this statement mean?
*December 12, 2012*

**Chemistry**

If 355 g Al(NO3)3 reacts with an excess of K2CrO4, how many moles of KNO3 would be produced?
*December 12, 2012*

**chemistry**

3.50 mol Al(NO3)3 reacts with 5.00 mols K2CrO4, the total number of moles of Al2(CrO4)3 and KNO3 would be? Here is the equation if it's needed. 2 Al(NO3)3(aq) + 3 K2CrO4(aq) → Al2(CrO4)3(s) + 6 KNO3(aq)
*December 12, 2012*

**Chemistry**

How many atoms of O are in 4 moles of (NH4)3PO4 - 6H2O? The answer is 2.41x10^25 I have no clue how to arrive at this answer.
*December 11, 2012*

**Mathematics of Retailing**

An owner of a laundry shop received an invoice for purchasing 200 bottles of liquid detergent at RM15 each, and 300 bottles of fabric softener at RM8 each. The invoice dated on 6th August 2010. He was offered trade discount 10% and 8%, with cash discount 10/10, 5/20, n/30. The...
*December 9, 2012*

**physics! please help!! **

A particle rotates counterclockwise in a circle of radius 6.5 m with a constant angular speed of 7.4 rad/s. At t = 0, the particle has an x coordinate of 3.3 m and y > 0 . A) Determine the x coordinate of the particle at t = 0.716 s. Answer in units of m ( I know this ...
*December 6, 2012*

**physics**

A particle rotates counterclockwise in a circle of radius 6.5 m with a constant angular speed of 7.4 rad/s. At t = 0, the particle has an x coordinate of 3.3 m and y > 0 . A) Determine the x coordinate of the particle at t = 0.716 s. Answer in units of m ( I know this ...
*December 6, 2012*

**physics help please!**

thank you!!!!! i must have messed up on my calculations
*December 6, 2012*

**physics help please!**

The motion of a piston in an auto engine is simple harmonic. The piston travels back and forth over a distance of 23 cm, and the piston has a mass of 1.7 kg. 2515 rpm 23 cm max speed of the piston 30.28757 m/s What is the maximum force acting on the piston when the engine is ...
*December 6, 2012*

**statistics**

Scores from a statistics exam are reported as deviation scores. Which of the following deviation scores indicates a higher position in the class distribution?
*December 6, 2012*

**physics**

A 28.6-g bullet is fired from a rifle. It takes 2.36 × 10-3 s for the bullet to travel the length of the barrel, and it exits the barrel with a speed of 710 m/s. Assuming that the acceleration of the bullet is constant, find the average net force exerted on the bullet.
*December 5, 2012*

**chemistry**

just a guess but would all but C be stable?
*December 4, 2012*

**chemistry**

A magic number is the name given to certain numbers of protons or neutrons that have a high correlation to stability in nuclei. Magic # of protons: 2,8,20,28,50,82 Magic # of neutrons: 2,8,20,38,50,82,126, 184 Using general trends, predict the stability of the following nuclei...
*December 4, 2012*

**calculus**

1. (30 points) Consider a manufacturer whose total cost of producing x items is given by c(x)=10000+5x+1/9x^2. a. What is the average cost function A(x)= c(x)/x? b. How many items should the manufacturer produce in order to minimize average cost? c. What is the smallest ...
*December 3, 2012*

**physics**

An object is projected upward from the surface of the earth with an initial speed of 2 km/s. The acceleration of gravity is 9.81 m/s^2. Find the maximum height it reaches. Answer in units of km.
*November 30, 2012*

**Math**

A rectangle area spans . The length must be 20ft more than the width. What are the dimensions?
*November 30, 2012*

**physics**

Wow thank you so much! This problem has been bothering me for a week now
*November 30, 2012*

**physics**

A hydraulic brake system is shown. The area of the piston in the master cylinder is 6.32 cm^2, and the area of the piston in the brake cylinder is 1.83 cm^2. The coeﬃcient of kinetic friction between the brake shoe and the wheel drum is 0.443. How large is the ...
*November 30, 2012*

**Math**

When rolling two dice, what is the probability that the sum is 7 given that one die is a 5?
*November 29, 2012*

**college physics**

A hydraulic brake system is shown. The area of the piston in the master cylinder is 6.32 cm^2, and the area of the piston in the brake cylinder is 1.83 cm^2. The coeﬃcient of kinetic friction between the brake shoe and the wheel drum is 0.443. How large is the ...
*November 29, 2012*

**chem**

pH= -log [H+] pH < 7 is acidic and pH > 7 is basic. for example pH= - log [1.0e-11M] pH= 11 therefore basic solution.
*November 29, 2012*

**physics**

this is a huge help! thanks again!
*November 29, 2012*

**physics**

Wow thank you. I was really lost.
*November 29, 2012*

**math**

you deposit $2200 in an account that pays 3% interest, after 15 years you withdraw, what is the balance if the interest is compounded continuously
*November 29, 2012*

**physics**

A liquid of density 1354 kg/m^3 ﬂows with speed 2.45 m/s into a pipe of diameter 0.29 m. The diameter of the pipe decreases to 0.05 m at its exit end. The exit end of the pipe is 7.82 m lower than the entrance of the pipe, and the pressure at the exit of the pipe is 1.4...
*November 29, 2012*

**Chemistry**

how do I convert moles of Cr2O3 to moles of H2CrO4? I don't understand what this means
*November 27, 2012*

**Chemistry**

3C3H8 + 20H2CrO4-> 9CO2 + 10Cr2O3 + 32H2O Suppose you want to make 1.50 g of chromium (III) oxide, how many ml of 6.25M chromic acid will you need to use if the percent yield of the reaction is 68.6%?
*November 27, 2012*

**Phoenix**

Why do you think Windows is so prevalent? What do the other systems have to offer that Windows does not? Who uses the other systems?
*November 27, 2012*

**Financial management**

what is the principle investment ? you have $1728.34 compounded daily at 3.4% and its invested for 9 years
*November 27, 2012*

**math**

for the equations y=5x+50 and y=6x+25, for how many hats will the cost be the same and what is that cost?
*November 26, 2012*

**Chemistry**

Sodium vapor lamps, use for public lighting, emits 489 nm yellow light. What energy is emitted by: a) an excited sodium atom when it generates a photon? b) 1 mole of excited sodium atoms at this wavelength?
*November 25, 2012*

**Chemistry**

This helped me with the amount in grams of Cr2O3, but what do I do with the 2nd part, the 35.0 ml of 6.26M chromic acid?
*November 23, 2012*

**Chemistry**

3C3H8 + 20H2CrO4-->9CO2 + 10 Cr2O3 + 32H2O What mass of chromium (III) oxide will be formed by complete reaction of 1.50g of propane with 35.0ml of 6.26M chromic acid?
*November 23, 2012*

**Chemistry**

a stock solution of perchloric acid is 75.5% perchloric acid and has a density of 1.67g/ml. What is the molarity of the solution?
*November 23, 2012*

**math**

How high is a wall that casts a 15ft shadow at the same time that a 4ft flag pole casts a 4ft shadow?
*November 23, 2012*

**college english**

what is a good attention getter sentence on carpal tunnel syndrome?
*November 21, 2012*

**statistics**

The reaction time of subjects to a certain psychological experiment is considered to be normally distributed with a mean of 20 seconds and a standard deviation of 4 seconds. What is the reaction time such that only 10% of subjects are faster?
*November 21, 2012*

**statistics**

The reaction time of subjects to a certain psychological experiment is considered to be normally distributed with a mean of 20 seconds and a standard deviation of 4 seconds. What is the reaction time such that only 10% of subjects are faster?
*November 21, 2012*

**statistics**

Entry to a certain University is determined by a national test. The scores on this test are normally distributed with a mean of 500 and a standard deviation of 100. Tom wants to be admitted to this university and he knows that he must score better than 70% of the students who ...
*November 20, 2012*

**Physics**

A roller coaster is initially at a height of 40 m above the ground and has an initial velocity of 15 m/s. Using conservation of energy, find the velocity of the roller coaster at a height of 5 m above the ground.
*November 19, 2012*

**Chemistry**

What mass of Uranium (in mg) is contained in 1ml of 4.55M (UO2)3(PO4)3 solution? How do I solve this? *all numbers are subscripts
*November 18, 2012*

**physics what am i doing wrong?**

I figured it out......i dont understand why no one has helped me yet in the past week
*November 16, 2012*

**physics what am i doing wrong?**

Three masses are arranged in the (x, y) plane. 3kg (0,0) 7kg (10,0) 6kg (0,3) What is the magnitude of the resulting force on the 3 kg mass at the origin? The value of the universal gravitational constant is 6.6726 × 10^−11 N · m^2/kg^2. Answer in units of N...
*November 16, 2012*

**can someone please help w/ physics?**

anybody? please?
*November 16, 2012*

**can someone please help w/ physics?**

An object of mass 154 kg moves in a smooth straight tunnel of length 2990 km dug through a chord of a planet of mass 3.19 × 10^24 kg and radius 1 × 10^7 m Find the eﬀective force constant of the harmonic motion. The value of the universal gravitational ...
*November 16, 2012*

**english**

Ms. Sue can you please check for #1 The Gerund Phrase is water skiing , sailing, and swimming Direct Object ?
*November 16, 2012*

**PHYSICS!**

An object of mass 154 kg moves in a smooth straight tunnel of length 2990 km dug through a chord of a planet of mass 3.19 × 10^24 kg and radius 1 × 10^7 m Find the eﬀective force constant of the harmonic motion. The value of the universal gravitational ...
*November 16, 2012*

**chemistry**

. What is the mass concentration (titer) is a solution of sulfuric acid with the molar concentration equivalent 0.5 mol/dm3?
*November 15, 2012*

**chemistry**

Potassium nitrate weighing 15 g was dissolved in water volume of 200 cm3. Calculate the mass fraction of KNO3 in solution.
*November 15, 2012*

**chemistry**

What is the mass of dry NaCl sample should be taken for 100 cm3 of 0.5 mol/dm3 aqueous solution?
*November 15, 2012*

**chemistry**

Determine the molality 0.8 mol/dm3 solution of Fe2 (SO) 4. Density equal to 1 g/cm3.
*November 15, 2012*

**chemstry**

What mass of sucrose must be taken for solution weight of 200 g, which is equal to molality 0.05 mol / kg?
*November 15, 2012*

**chemistry**

What mass of sucrose must be taken for solution weight of 200 g, which is equal to molality 0.05 mol / kg?
*November 15, 2012*

**social studies**

which of the following statements is supported by the information in the map please help
*November 14, 2012*

**physics**

A 11.1-kg block rests on a horizontal table and is attached to one end of a massless, horizontal spring. By pulling horizontally on the other end of the spring, someone causes the block to accelerate uniformly and reach a speed of 3.12 m/s in 1.17 s. In the process, the spring...
*November 13, 2012*

**physics**

When an object of mass m1 is hung on a vertical spring and set into vertical simple harmonic motion, it oscillates at a frequency of 14.2 Hz. When another object of mass m2 is hung on the spring along with the first object, the frequency of the motion is 3.40 Hz. Find the ...
*November 13, 2012*

**physics**

A block rests on a frictionless horizontal surface and is attached to a spring. When set into simple harmonic motion, the block oscillates back and forth with an angular frequency of 9.0 rad/s. The drawing shows the position of the block when the spring is unstrained. This ...
*November 13, 2012*

**physics**

A 82.5-kg climber is scaling the vertical wall of a mountain. His safety rope is made of a material that, when stretched, behaves like a spring with a spring constant of 1.82 x 103 N/m. He accidentally slips and falls freely for 0.739 m before the rope runs out of slack. How ...
*November 13, 2012*

**Physics**

In New Hampshire the average horizontal component of Earth's magnetic field in 1912 was 16 uT, and the average inclination or "dip" was 73 degrees. What was the corresponding mag-nitude of Earth's magnetic field?
*November 12, 2012*

**business calculus**

X=D(p)=400-p
*November 12, 2012*

**business calculus**

X=D(p)=400-p
*November 12, 2012*

**Math**

Draw two scalene triangles that are not congruent, but have exactly five sets of parts (sides and angles) that are congruent. Make a drawing that is to scale. Label yourmeasurements.
*November 8, 2012*

**Chemistry**

what mass of nitrogen dioxide (8NO2) will form by reaction of 3.50 mole of perchloric acid (13HClO4) with excess methylamine (8CH3NH2)? Answer is 99.1 g. How do you work this?
*November 6, 2012*

**Chemistry**

*answer is 4.14g
*November 6, 2012*

**Chemistry**

what mass of water will be formed by reaction of 3.50g of methylamine (8CH3NH2) with 15.0g of perchloric acid (13HClO4)? Answer is 99.1. How do you work this?
*November 6, 2012*

**Chemistry for Eng.**

delta H3: energy associated with the formation of water-ion interactions delta Hsoln: the enthalpy of solution
*November 1, 2012*

**math**

A section of the railway has a slope of about 0.73. In this section, a vertical change of 1 unit corresponds to a horizontal change of what length?
*October 31, 2012*

**AP Physics C**

An electron follows a helical path in a uniform mag-netic field of magnitude 0.300 T. The pitch of the path is 6.00 um, and the magnitude of the magnetic force on the elec-tron is 2.00x10^-15 N. What is the electron's speed?
*October 29, 2012*

**Physics: Kinematics**

A speed boat moving at 33.7 m/s approaches a no-wake buoy marker 93.3 m ahead. The pilot slows the boat with a constant deceleration of 2.9 m/s 2 by reducing the throttle. How long does it take the boat to reach the buoy? current work done: x = Vot + (1/2)at^2 93.3 = 0(t) + (1...
*October 29, 2012*

**Art 101 college**

Explain how Florence reflects the ideals of the dominant city-state and how some of the geographical, economical, social, and artistic forces shape this ideal. Use one example from Gardner’s Art through the Ages and one example from the Internet.
*October 27, 2012*

**Algebra 2**

(index of 3)square root of 3r-6(equals 3)
*October 26, 2012*

**physics**

As a result of friction, the angular speed of a wheel changes with time according to d(theta)/dt = w0 e^-(aplpha*t) where w0 and alpha are constants. The angular speed changes from an initial angular speed of 4.87 rad/s to 4.27 rad/s in 33.93s. A) Determine the magnitude of ...
*October 26, 2012*

**science**

A balloon with an initial volume of 2.8L at a temperature of 296K is warmed to 375K . What is its volume at the final temperature? (Assume constant pressure.)
*October 22, 2012*

**Physics**

A military helicopter on a training mission is flying horizontally at a speed of 60.0 m/s and accidentally drops a bomb (fortunately not armed) at an elevation of 350 m. You can ignore air resistance. Find the horizontal and vertical components of its velocity just before it ...
*October 21, 2012*