Saturday

February 6, 2016
Total # Posts: 273

**science**

Water is useful for reducing friction between objects. However you also learned that (due to friction) moving water causes rough rocks to become smooth. How can this be?
*November 3, 2015*

**Quantitative Math**

A bacteria has a doubling period of 5 days. If there are 3250 bacteria present now, how many will there be in 40 days? I've found the growth rate to be 0.14869, but I can not find the amount of bacteria.
*November 1, 2015*

**Chemistry**

A line in the Balmer series of hydrogen has a wavelength of 486 nm. From what state did the electron originate? In what region of the electromagnetic spectrum is this line observed?
*October 21, 2015*

**Calculus**

Oil is leaking from an oil tanker, and an expanding circle of oil is spreading on the ocean. The radius, r, of the circle measured in inches is modeled by the function r(s)=3 sqrt root s , where s is time in seconds. The area of the spill when seconds is s=5 seconds.
*September 18, 2015*

**Pre-Calculus**

A rectangular window is topped with a semicircle. The height of the rectangular part is 1 more than 3 times its width, w meters. Which function represents the total area, A, of the window in terms of the width?
*September 10, 2015*

**6th grade math**

I have that same problem too and the answer is 11 836/1000
*August 31, 2015*

**Chemistry**

A monoprotic acid of 0.065 M concentration has a pH of 2. 75. Is this a strong or weak acid?
*April 23, 2015*

**Chemistry**

You have to prepare a pH 3.50 buffer, and you have the following 0.10M solutions available HCOOH, CH3COOH, H3PO4,CHOONa, CH3COONa, and NaH2PO4. a) What solutions would you use? b) How many milliliters of each solution would you use to make approximately 1 liter of the buffer? ...
*April 21, 2015*

**Math**

The front wheel of the worlds largest bicycle has a diameter of 3.05 metres. How many times will this wheel revolve in 1 kilometre?
*March 23, 2015*

**English**

Did you ever get the answers for this test
*March 13, 2015*

**Science **

Zn + 2HCl - ZnCl2 + H2 Assuming the acid was in excess (so all of the zinc reacts), how many mols of hydrogen would you produce?
*March 9, 2015*

**Introduction programing visual basic**

break even analysis. suppose a certain product sells for a dollars per unit. then the revenue from selling x units of the product is ax dollars if the cost of producting each unit of the product is b dollars and the company has overhead cost of c dollars then the total cost of...
*March 4, 2015*

**Introduction programing visual basic**

break even analysis. suppose a certain product sells for a dollars per unit. then the revenue from selling x units of the product is ax dollars if the cost of producting each unit of the product is b dollars and the company has overhead cost of c dollars then the total cost of...
*March 4, 2015*

**Chemistry**

The tomato is dropped. What is the velocity, v, of the tomato when it hits the ground? Assume 94.7% of the work done in Part A is transferred to kinetic energy, E, by the time the tomato hits the ground.
*December 7, 2014*

**Math**

Simultaneous equations- The tickets for a sports club disco cost £2 for members and £3 for non-members. a)The total ticket money collected was £580. x tickets were sold to members and y tickets were sold to non-members. Use this information to write down an ...
*November 1, 2014*

**Physics **

A 66.0 kg base runner begins his slide into second base when moving at a speed of 4.4 m/s. The coefficient of friction between his clothes and Earth is 0.70. He slides so that his speed is zero just as he reaches the base. (a) How much mechanical energy is lost due to friction...
*October 25, 2014*

**math**

Are negative numbers are integers? True or false
*August 27, 2014*

**Art and Design/ History **

How did the first world war play an important role in many aspects of Art Deco and designers, How did it change the role of women and men?
*August 4, 2014*

**alegerba**

In the expression 90+5z, the coefficient is
*April 15, 2014*

**Science - Please Check my Answer 2**

no
*February 27, 2014*

**Neuroscience**

What are the 3 nuclei in the midbrain?
*February 11, 2014*

**pre-algebra**

92
*December 21, 2013*

**Physics`**

A field hockey player's arm and stick form a rigid segment. Assuming she hits the ball when the stick is vertical, which of the following would result in the greatest velocity of the end of her stick immediately before she hits the ball? a) She stands still and swings her ...
*November 25, 2013*

**Physics**

A golf club is swung with an average angular acceleration of 1.7 rad/s^2. If thee time from start of the swing until the club hits the ball is .7 s, what is the angular velocity of the club when it strikes the ball?
*November 7, 2013*

**Physics**

Calculate the force of gravitational attraction between two spheres of mass 10.1kg and 45.2 kg that are 38.5m apart.
*November 7, 2013*

**Physics**

Calculate the force of gravitational attraction between two spheres of mass 10.1kg and 45.2 kg that are 38.5m apart.
*November 7, 2013*

**Physics**

A sample of an unknown material appears to weigh 275 N in air and 160 N when immersed in alcohol of specific gravity 0.700. What is the volume of the material? What is the density of the material?
*October 28, 2013*

**Physics**

A 2.0 mm diameter copper ball is charged to +42 nC. What fraction of its electrons have been removed? The density of copper is 8,920 kg/m3
*October 1, 2013*

**Physics**

a)What frequency is received by a person watching an oncoming ambulance moving at 120 km/h and emitting a steady 700 Hz sound from its siren? The speed of sound on this day is 345 m/s. b)What frequency does she receive after the ambulance has passed?
*September 3, 2013*

**math**

The number of customers that visit a local small business is 37,800 and has been continuously declining at a rate of 1.7% each year. What is the approximate number of customers that visit the business in 12 years?
*July 28, 2013*

**algebra**

You are using 0.05 gallons per mile of a SUV gas tank that holds 16 gallons. Note: this equation has a negative slope (m). Use x-values: 0, 160, and 320. I think the problem should be y=.05x+16 Confused since the teacher says it has a negative slope.
*May 13, 2013*

**Science **

If A tank with a flat bottom is filled with water to a height of four meters. what is the pressure at any point at the bottom of the tank? my teacher wants me to ignore atmospheric pressure when calculating my answer A. 3.5 kPa B. 3,500 kPa C. 34.3 kPa D. 34,300 kPa
*May 7, 2013*

**Physics**

what formula did you use???
*May 6, 2013*

**Hess's law**

I need some help with this one please... A+B ----> 2 D H= -765.3 kj S= 344 j/k C ------> D H= 521 kj S= -171 j/k calculate G at 298 K for A+B ------> 2C I know I need to use the formula G= H-TS but I dont know how to get the numbers.
*March 20, 2013*

**english**

How do you diagram this sentence: Driving to the mall, Ann stopped on the way to visit her girlfriend.
*February 18, 2013*

**Chemistry**

The heat lost or gained by a system is related to its temperature change by a property called its heat capacity. The molar heat capacity of metals at or above room temperature equals 24.92 J K-1mol-1. The temperature of a block of copper metal (molar mass 63.55 g mol-1) fell ...
*February 6, 2013*

**dress making **

im pretty sure im right on most the question, just wanna make sure before i submit!! help Mrs. Shotto was once one of your regular customers, but she hasn't asked to have any garments made in approximately one year. You note she has lost weight. She would like you to make ...
*January 28, 2013*

**dress making **

1. Which one of the following is the most complete and accurate definition of fiber? A. A stringy substance from plants B. The hair of an animal C. Man-made threads and yarns D. Basic raw material from which fabric is made 2. An example of a natural fiber is A. nylon. B. ...
*January 25, 2013*

**chem really need help!**

i think my equation is wrong. should it be C4H6O4Hg + Na2SO4 -----------> Na(C4H6O4)+ HgSO4 but then there are no coefficients
*January 17, 2013*

**chem really need help!**

33.82g/318.678= 0.106 mols Mercury ii acetate 9.718g/142.04= 0.0684 mols sodium sulfate
*January 17, 2013*

**chem really need help!**

C4H6O4Hg + Na2SO4 -----------> 2Na(C4H6O4)+ HgSO4
*January 17, 2013*

**chem really need help!**

If a solution containing 33.82 g of mercury(II) acetate is allowed to react completely with a solution containing 9.718 g of sodium sulfate, how many grams of solid precipitate will be formed? How many grams of the reactant in excess will remain after the reaction?
*January 17, 2013*

**please help!!**

If a solution containing 33.82 g of mercury(II) acetate is allowed to react completely with a solution containing 9.718 g of sodium sulfate, how many grams of solid precipitate will be formed? How many grams of the reactant in excess will remain after the reaction?
*January 17, 2013*

**chem please help!**

If a solution containing 33.82 g of mercury(II) acetate is allowed to react completely with a solution containing 9.718 g of sodium sulfate, how many grams of solid precipitate will be formed? How many grams of the reactant in excess will remain after the reaction?
*January 17, 2013*

**Chemistry**

If a solution containing 33.82 g of mercury(II) acetate is allowed to react completely with a solution containing 9.718 g of sodium sulfate, how many grams of solid precipitate will be formed? How many grams of the reactant in excess will remain after the reaction?
*January 17, 2013*

**basic chem**

If a solution containing 33.82 g of mercury(II) acetate is allowed to react completely with a solution containing 9.718 g of sodium sulfate, how many grams of solid precipitate will be formed? How many grams of the reactant in excess will remain after the reaction?
*January 17, 2013*

**6th grade math**

a tri angle has a base of 5.2 and a hieght of 19cm
*January 9, 2013*

**Darin**

wouldn't it be 5%?
*November 30, 2012*

**Math**

there would be 5 on each team hope i helped (:
*November 29, 2012*

**Chemistry**

A sample of oxygen is collected in a 387 mL container over water at 15◦C, and the barom- eter reads 738 torr. What volume would the dry gas occupy at 781 torr and 15◦C? Water’s partial pressure at 15◦C is 12.8 torr. Answer in units of mL
*November 20, 2012*

**Chemistry**

A sample of hydrogen (2.02 g/mol) effuses through a porous container about 8.85 times faster than an unknown gas. Estimate the molar mass of the unknown gas. Answer in units of g/mol
*November 20, 2012*

**Chemistry**

A meteorological balloon had a radius of 1.1 m when released at sea level at 20◦C. It ex- panded to a radius of 5 m when it had risen to its maximum altitude, where the temperature was −20◦C. What was the pressure inside the balloon at that altitude? The ...
*November 20, 2012*

**Chemistry**

Use van der Waals’ equation to calculate the pressure exerted by 2.33 mol of ammo- nia at −3.7◦C in a 1.25 L container. The van der Waals’ constants for ammonia are a = 4.00 L2·atm/mol2 and b = 0.0400 L/mol. (The values for a and b have been ...
*November 20, 2012*

**Chemistry**

Oxygen can be produced in the laboratory by the reaction 2 KClO3(s) → 2 KCl(s) + 3 O2(g) . How much potassium chlorate is needed to produce 2.75 L of oxygen, collected over water at 37◦C and 94.9 kPa? The vapor pressure of water at 37◦C is 6.28 kPa. 1. 0.189 ...
*November 20, 2012*

**science**

According to the principle of superposition, in a stack of undisturbed sedimentary rocks, the oldest rocks are _____. Gaps in rock layers are called ____. Which of the following is not a type of unconformity?
*November 16, 2012*

**physics**

You are given angular velocity initial, angular acceleration, and time. use wf=wi+at wf=0+(0.630rad/s)*(3s)
*November 4, 2012*

**Physics**

The asteroid belt circles the sun between the orbits of Mars and Jupiter. One asteroid has a period of 10 Earth years. a) What is the asteroid's orbital radius? b)What is the asteroid's orbital speed?
*October 23, 2012*

**physics**

A ball is thrown from a point 1.38 m above the ground. The initial velocity is 19.9 m/s at an angle of 33.8° above the horizontal. Find the maximum height of the ball above the ground. Calculate the speed of the ball at the highest point in the trajectory.
*September 23, 2012*

**Physics**

A person climbs from a Paris metro station to the street level by walking up a stalled escalator in 96.5 s. It takes 60.0 s to ride the same distance when standing on the escalator when it is operating normally. How long would it take for him to climb from the station to the ...
*September 20, 2012*

**Physics**

A particle's constant acceleration is north at 108 m/s2. At t = 0, its velocity vector is 61.7 m/s east. At what time will the magnitude of the velocity be 102 m/s?
*September 20, 2012*

**grammar**

Click on the box below to choose the correct sentence pattern for the sentence below. There is good reason to be thankful. OPTIONS: Question patternS-V-DOS-LV-PNS-VS-LV-PAS-V-IO-DOE-V-SS-V-DO-OC
*August 22, 2012*

**grammar**

What is the correct sentence pattern for...I hereby declare Tuesday Shakespeare Day. OPTIONS: Question patternS-V-DOS-LV-PNS-VS-LV-PAS-V-IO-DOE-V-SS-V-DO-OC
*August 22, 2012*

**science**

that answer is incorrect
*August 10, 2012*

**science**

A soccer ball is kicked with an initial speed of 8.4 m/s in a direction 22.0° above the horizontal.Find the magnitude and direction of its velocity at the following times. (Take the +x axis to be parallel to the ground, in the direction that the ball is kicked.)0.250 s ...
*August 10, 2012*

**physics**

Two strings are adjusted to vibrate at exactly 224 Hz. Then the tension in one string is increased slightly. Afterward, three beats per second are heard when the strings vibrate at the same time. What is the new frequency of the string that was tightened? (in Hz)
*August 7, 2012*

**Calc**

The arc of the parabola y=x^2 from (1,1) to (2,4) is rotated about the y-axis. Find the area of the resulting surface.
*June 6, 2012*

**calculus**

The base of a solid consists of the region bounded by the parabola y=rootx, the line x=1 and the x-axis. Each cross section perpendicular to the base and the x-axis is a square. Find the volume of the solid.
*June 6, 2012*

**Calc**

Are you sure about the 4w (324/w^2)? Shouldn't it be 8w (324/w^2), since you are multiplying the four sides by the cost of $2 per square foot?
*June 5, 2012*

**Calc**

A closed box with a square base is to be constructed so that its volume is 324 cubed feet. The material for the top and bottom cost is $3 per square foot, and that for the sides $2 per square foot. Find the dimensions of the box so that the cost will be minimum.
*June 5, 2012*

**Math 10**

A cylinder has a surface area of 250cm2. The height is twice as big as the radius. What is the height of the cylinder?
*May 21, 2012*

**Finance**

The Isberg Company just paid a dividend of $0.75 per share, and that dividend is expected to grow at a constant rate of 5.50% per year in the future. The company's beta is 1.25, the market risk premium is 5.00%, and the risk-free rate is 4.00%. What is the company's ...
*April 2, 2012*

**Finance**

Scanlon Inc.'s CFO hired you as a consultant to help her estimate the cost of capital. You have been provided with the following data: rRF = 4.10%; RPM = 5.25%; and b = 1.15. Based on the CAPM approach, what is the cost of equity from retained earnings? Several years ago ...
*April 2, 2012*

**College Algebra**

The height of a box is 3cm less than the width. The length is 2cm less than the width. The volume is 50cm^3. what is the width of the box?
*April 2, 2012*

**algebra**

Which situation would most likely be represented by a negative correlation: hours of practice and your golf score, hours of practice and the number of baskets you make in basketball, or hours of practice and the cost of a computer? Hint: In golf, the lower the score, the better.
*March 19, 2012*

**Chemistry**

Sorry, its 0.150 M solution of ammonia at 25 degrees celsius
*March 18, 2012*

**Chemistry**

At 25 degrees Celsius, the base ionization constant for NH3 is 1.8 x ^-5. Determine the percentage ionization of a M solution of ammonia at 25 degree Celsius.
*March 18, 2012*

**Chemistry**

How much heat in kJ is lost when 100.0g of steam at 200 deg C is cooled down until it forms ice at -30.0 deg C?
*March 6, 2012*

**Chemistry**

Calculate the heat (in kJ) required to change 40.0g of ice at -30.0 deg C to steam at 150.0 deg C?
*March 6, 2012*

**Intergrated Math**

Use the definitions and theorems of this section to evaluate and simplify the following expression. Be sure to express answers with positive exponents. (b ^4)^ 2
*December 29, 2011*

**General chemistry**

How much energy is released by the combustion of 1.00 mol of octane, C8H18?
*November 7, 2011*

**Chemistry**

Calculate the average mass (in amu) of 1 methane molecule (to .01 amu)
*November 1, 2011*

**Chemistry**

How do you find the number of bond angles for an octahedral structure? I believe it's more than one answer
*October 28, 2011*

**Chemistry**

How do you figure out the number of bond angles for an octahedral? It's more than one answer?
*October 28, 2011*

**Chemistry**

Predict the formal bond angles about the central atom for the following molecules: TeBr4 Express your answers using three significant figures separated by a comma. What are the bond angles for an octahedral structure and how many?
*October 28, 2011*

**Chemistry**

Describe what a chemical bond is in terms of electron density between two atoms. What are the bond angles for an octahedral structure and how many? Predict the formal bond angles about the central atom for the following molecules: TeBr4 Express your answers using three ...
*October 28, 2011*

**physics**

A sample of an unknown material appears to weigh 285 N in air and 165 N when immersed in alcohol of specific gravity 0.700. (a) What is the volume of the material? Answer is in m3 (b) What is the density of the material? Answer is in kg/m3
*October 27, 2011*

**physics**

(a) Calculate the mass flow rate (in grams per second) of blood (ρ = 1.0 g/cm3) in an aorta with a cross-sectional area of 2.0 cm2 if the flow speed is 33 cm/s. Answer is in g/s (b) Assume that the aorta branches to form a large number of capillaries with a combined cross...
*October 27, 2011*

**Chemistry**

Rank the carbon-carbon bonds in order of decreasing bond length. Rank carbon-carbon bonds from highest bond length to lowest. To rank bonds as equivalent, overlap them. 1,2,3
*October 11, 2011*

**Chemistry**

The dipole moment (mu) of HBr (a polar covalent molecule) is 0.851 D (debye), and its percent ionic character is 12.6 %. Estimate the bond length of the H-Br bond in picometers.
*October 7, 2011*

**Chemistry**

The bond in O2 is shorter than the O-O bond in compounds that contain an O-O single bond. Explain this observation.
*October 7, 2011*

**Chemistry**

The Lewis structure of O2
*October 7, 2011*

**Chemistry**

Explain why it is necessary to form a double bond in the Lewis structure.
*October 7, 2011*

**Chemistry**

Which of the subshells in the electron configuration of Hf behave as core orbitals Check all that apply 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d
*October 4, 2011*

**Chemistry**

What do we call the part of the universe that is not part of the system
*October 4, 2011*

**Chemistry**

What is the kinetic energy of the emitted electrons when cesium is exposed to UV rays of frequency 1.7×10^{15} Hz?
*September 27, 2011*

**Physics**

A horizontal spring attached to a wall has a force constant of 780 N/m. A block of mass 1.70 kg is attached to the spring and oscillates freely on a horizontal, frictionless surface as in the figure below. The initial goal of this problem is to find the velocity at the ...
*September 27, 2011*

**Chemistry**

In the recent Chem Activities, we have been learning about how Coulombic attractions and repulsions determine properties of atoms like ionization energy and atomic radius. We have made two assumptions not completely justified by the data we had up to this point: electrons are ...
*September 26, 2011*

**Math**

A ten-pin bowling ball has a volume of about 5274 cm3. A candlepin (8) bowling ball has a volume of about 48 in3. About how much greater is the volume of a ten-pin bowling ball than the volume of a candlepin bowling ball?
*September 25, 2011*

**Math**

Tonia deposited a total of $174.52 into her checking account. She also withdrew a total of $186.15. Use addition to find the net change in Tonia’s checking account.
*September 25, 2011*

**Chemistry**

What is the frequency of radiation that has a wavelength of 13 \mu m, about the size of a bacterium?
*September 22, 2011*