# Posts by brittany

Total # Posts: 939

**Pre Calc Trig**

Verify the following: tan( a + p/2) = -cot a a= alpha and p= pie since I do not have that button.

*March 29, 2011*

**Physics**

Oh and use the speed of sound of air (at 20 degrees C) to be v=343m/s.

*March 24, 2011*

**Physics**

Since it one end is open and the other is shut, the ear canal is considered a closed pipe. We set L = 2.3cm = 0.023m. The frequency for a closed pipe is fn=n(v/4L)=v/wavelength where n=1,2,3,.. referring to the number of overtones/harmonics. L=(1/4)*wavelength so we solve for ...

*March 24, 2011*

**algebra 2**

if the length and width of the rectangle are 5 and 11 inches respectivly what is the approimate circufrence of the circle if the rectangle is inscribed inside the circle?

*March 24, 2011*

**Chemistry**

Describe how to prepare an aqueous 100 mL stock solution of 2 M sodium chloride solution.

*March 22, 2011*

**physics**

A car traveling at 26 m/s undergoes a constant decleration of 12 m/s^2. About how long di=oes it take the car to come to a stop?

*March 11, 2011*

**perimeter and area**

hvhj

*March 9, 2011*

**spanish**

True

*March 6, 2011*

**College Physics**

Vector A points in the negative y direction and has a magnitude of 6 units. Vector B has twice the magnitude and points in the positive x direction. Find the direction and magnitude of vec A-B and Vec B-A?

*March 2, 2011*

**Calc**

"Let f(x,y)=2(x^2)y-(y^3)+x-4. a) Find the local linearization of f at (3,1) b) Compute the directional derivative of f at (3,1) in the direction towards the point (-2,3). At (3,1), is the function f increasing or decreasing in the direction towards the point (-2,3)? Give...

*March 1, 2011*

**Calc**

The temperature at any point in the plane is given by the function T(x,y)= 100/(x^2+y^2+1). Find the direction at the point (3,2) in which the temperature does not increase or decrease. Help, please? Thanks!

*February 28, 2011*

**Calc**

The question that I'm stuck on is this: "Let f(x,y)= x^(2)*ln(y). Find the average rage of change of f as you go from (3,1) to (1,2) and find the instantaneous rate of change of f as you leave the point (3,1) toward (2,1)." Any help would be appreciated. Thanks!

*February 27, 2011*

**Calc: Difference quotients**

"Use difference quotients with delta(x)=0.1 and delta(y)=0.1 to estimate fx(1,3) and fy(1,3) where f(x,y)=e^(-x)sin(y)." I don't know how to solve this problem. Could someone walk me through it? Thank you so much!

*February 27, 2011*

**chemistry**

What is the pH of a solution prepared by dissolving 7.5g HCl in water to make 375mL of solution?

*February 27, 2011*

**physics**

A water balloon dropped from a dorm window does not break on impact. From what height would you need to drop the balloon to double the speed of the balloon?

*February 25, 2011*

**math**

a river flows at 2km/hr and sarah takes 6 hrs to row 16km up the river and 16km back.how fast did she row?

*February 23, 2011*

**5th grade math**

the johnsons has ben verry bussy and havet done laundry in several weeks the dirty cloth pile hase 540 cloths they figur they can put 27 pices of clothing in a singal load. how many loads of laundry will the johnsens family to do to wash all the itams of clothing

*February 15, 2011*

**sciene**

A kid applies a force of 70 N to a ball over 1.1 meters. How much work did he do on the ball?

*February 9, 2011*

**Chemistry**

Thanks. Would it matter which molarity I use if I used M1V1 = M2V2

*February 5, 2011*

**Chemistry**

How do I find the molarity of Fe(SCN)2+? I know the molarity of SCN=0.1 and the molarity of Fe is 0.0001. The volume of SCN is 5 mL and the volume of the Fe is also 5mL. I also think that I use M1V1=M2V2.

*February 5, 2011*

**Chemistry**

How many moles of dinitrogen pentoxide are needed to produce 1.25 moles of nitric acid?

*February 3, 2011*

**Chemistry**

How many moles of nitric acid will be produced when 0.35 moles of water reacts?

*February 3, 2011*

**math**

In a gift wrapping department, a customer can choose from x different papers, y different ribbons, and z different greeting cards. There are 160 different paper, ribbon, and greeting card combinations possible. List three of the possible combinations. Need help...please.

*February 2, 2011*

**math**

The third and seventh terms of an arithmetic sequence are 10 and 20. 1) What is the value of the 1st term? 2) What is the value of the 9th term? 3) What is the equation to find the nth term in the sequence? HELP!! PLEASE!!

*February 2, 2011*

**Chemistry 1**

How many grams of a stock solution that is 92.5 percent H2SO4 by mass would be needed to make 250 grams of a 35.0 percent by mass solution? Can you please teach me how to do this? I get the other stoichiometry stuff, but this one tripped me up because I don't know how to ...

*February 1, 2011*

**chemistry**

A 0.100 mol sample of H2S is placed in a 10.0 L reaction vessel and heated to 1132°C. At equilibrium, 0.0285 mol H2 is present. Calculate the value of Kc for the reaction below at 1132°C. 2 H2S(g) 2 H2(g) + S2(g)

*January 31, 2011*

**Calculus**

A particle moves at varying velocity along a line and s=f(t) represents the particle's distance from a point as a function of time, t. Sketch a possible graph for f if the average velocity of the particle between t=2 and t=6 is the same as the instantaneous velocity at t=5...

*January 29, 2011*

**Chem**

What would be the resulting molarity of a solution made by dissolving 21.9 grams of KCl in enough water to make an 869-milliliter solution?

*January 27, 2011*

**Calc**

lim as x --> infinity of (x^2-16)/(x-4) is 8 By graphing, find an interval for near zero such that the difference between your conjectured limit and the value of the function is less than 0.01. In other words, find a window of height 0.02 such that the graph exits the sides...

*January 25, 2011*

**physics**

Can you help me with this one also? I know how to do it with 3 vectors but I can't seem to draw it with 4 vectors. The magnitudes of the four displacement vectors shown in the drawing are A=16.0 m, B=11.0 m, C=12.0 m, and D=26.0 m. Determine the (1) magnitude and (2) ...

*January 23, 2011*

**need help**

i'm in the 4th grade i need a socialstudy project to do rightnow i cant seam to think of anything can you help me please and thankyou

*January 23, 2011*

**physics**

A person is standing at the edge of the water and looking out at the ocean (see the drawing). The height of the person’s eyes above the water is h=1.6 m, and the radius of the earth is R=6.38x10^6 m (use as a precise value). (1) How far is it to the horizon (in meters, ...

*January 23, 2011*

**calculus**

Use a graph to estimate the limit: lim θ->0 (sin(5θ)/θ) Note: θ is measured in radians. All angles will be in radians in this class unless otherwise specified.

*January 22, 2011*

**Calculus**

A 0.3 ml dose of a drug is injected into a patient steadily for 0.35 seconds. At the end of this time, the quantity, Q, of the drug in the body starts to decay exponentially at a continuous rate of 0.4 percent per second. Using formulas, express Q as a continuous function of ...

*January 20, 2011*

**Calculus**

Consider the function f(x) = 5x^3 +5x^2 + 7, and let c be a number in the interval [0.1] . For what values of k is there a c in this interval such that f(c)=k? ______≤k≤______

*January 20, 2011*

**Physics**

9.6x10^-19

*January 19, 2011*

**Calculus**

According to Car and Driver, an Alfa Romeo going 70 mph requires 177 feet to stop. Assuming that the stopping distance is proportional to the square of the velocity, find the stopping distance required by an Alfa Romeo going at 55 mph and at 115 mph.

*January 19, 2011*

**Math**

What is the value of x? A isosceles triangle: bottom - x+3 one side - 2x+5 other side - 3x+2

*January 17, 2011*

**calculus**

On the graph of f(x)=6sin(8πx), points P and Q are at consecutive lowest and highest points with P occuring before Q. Find the slope of the line which passes through P and Q.

*January 15, 2011*

**Calculus**

In the year 2005, a picture supposedly painted by a famous artist some time after 1815 but before 1865 contains 96.5 percent of its carbon-14 (half-life 5730 years). From this information, could this picture have been painted by this artist? Approximately how old is the ...

*January 13, 2011*

**Calculus**

The half-life of radioactive strontium-90 is approximately 31 years. In 1960, radioactive strontium-90 was released into the atmosphere during testing of nuclear weapons, and was absorbed into people's bones. How many years does it take until only 11 percent of the ...

*January 13, 2011*

**math**

so you will be using the formula y=mx+b to plug the given values into. m=slope which is 8, here b=y-intercept which is 5 so your slope-intercept equation is... y=8x+5

*January 13, 2011*

**Physics**

Density of marble is 2.7 x 10^3 kg/m^3... Idk if that helps?

*January 4, 2011*

**Physics**

A ball of mass 0.640 kg moving east (+x direction) with a speed of 3.00 m/s collides head-on with a 0.740 kg ball at rest. If the collision is perfectly elastic, what will be the speed and direction of each ball after the collision?

*December 19, 2010*

**Maths**

I need help in this subject not to answer a question that I don't even understand.So somebody needs to help me understond this question.Not give me another question to answer.ok.ok

*December 18, 2010*

**math**

volume of a triangular prism

*December 16, 2010*

**Chemistry URGENT**

If a student starts with 615g of Co(NO3)2 and obtains a 57.3% yield of CoS, what mass of CoS is isolated? Co(NO3)2 + K2S ---> CoS + 2KNO

*December 16, 2010*

**Chemistry**

If a student starts with 615g of Co(NO3)2 and obtains a 57.3% yield of CoS, what mass of CoS is isolated? Co(NO3)2 + K2S ---> CoS + 2KNO3

*December 16, 2010*

**geography**

Affordable housing and improved transportation allowed people to begin to move away from central cities to the suburbs Think: When did affordable housing and highways come about? The industrial revolution gave rise to urbanization Think: When was the first occurrence of ...

*December 15, 2010*

**Chemistry**

I thought it was going to be easier than that.. honestly.. I'm better with math like calculus and formulas.

*December 15, 2010*

**Chemistry**

The four quantum numbers for the last electron placed in the orbitals of a certain element are: n=3 l=2 m of l=0 and m of s=-1/2. What is the element?

*December 15, 2010*

**General Chemistry**

Well I'm studying for my final and he gave us an answer key and with a spin down it says that the answer is nickel.. SOO I'm trying to make sense of it but I understand what n is what l is but how do you figure out what the elements are from ml? And all of that put ...

*December 14, 2010*

**General Chemistry**

The four quantum numbers for the last electron placed in the orbitals of a certain element are: n=3 l=2 m of l=0 and m of s=-1/2. What is the element? I need help with this part of chemistry I have NEVER understood this ever. I know how to do the configurations but not this. I...

*December 14, 2010*

**hum 176**

Write a thesis sentence about a movie stating how and why it is more than just a piece of entertainment. The thesis must include why it is a legitimate form of popular culture. Keep in mind factors such as influence and controversy.

*December 13, 2010*

**Physics**

The front 1.20 m of a 1550 kg car is designed as a "crumple zone" that collapses to absorb the shock of a collision. (a) If a car traveling 26.0 m/s stops uniformly in 1.20 m, how long does the collision last? cannot_evaluate s (b) What is the magnitude of the ...

*December 9, 2010*

**history**

Thank You!

*December 9, 2010*

**history**

Why did the Supreme Court rule that segregation was constitutional?

*December 9, 2010*

**Chemistry**

a 2.4375 g sample containing a mixture of KClO3 + NaCl is heated and undergoes a mass loss of 0.6191g. What percent of KClO3 is in the mixture?

*December 9, 2010*

**Chemistry**

a 2.4375 g sample containing a mixture of KClO3 + NaCl is heated and undergoes a mass loss of 0.6191g. What percent of KClO3 is in the mixture?

*December 9, 2010*

**Chemistry**

a 2.4375 g sample containing a mixture of KClO3 + NaCl is heated and undergoes a mass loss of 0.6191g. What percent of KClO3 is in the mixture?

*December 9, 2010*

**Chemistry**

a 2.4375 g sample containing a mixture of KClO3 + NaCl is heated and undergoes a mass loss of 0.6191g. What percent of KClO3 is in the mixture?

*December 9, 2010*

**Chemistry**

A 2.4375 g sample containing a mixture of KClO3 and NaCl is heated and under goes a mass loss of 0.6191 g. What is the percent of KClO3?

*December 9, 2010*

**Chemistry**

I ended up getting 42.718333 not rounded to sig figs but does the excess of hydrochloric acid have anything to do with the answer and what about the STP?

*December 8, 2010*

**Chemistry**

If you have Hydrochloric acid, how many grams of aluminum must you use to produce 57.0 L of hydrogen at STP? 2Al(s)+6HCl(aq) --> 3H2(g)+2AlCl3(aq)

*December 8, 2010*

**Chemistry**

The specific heat capacity of Lead is 0.127J/degrees C*g. What is the molar heat capacity of Lead? What is the heat capacity of a lead cylinder that has a mass of 235000g?

*December 8, 2010*

**chemistry**

specific heat of water there isnt one?

*December 8, 2010*

**chemistry**

How much heat energy in KJ is evolved by a reaction in a calorimeter in which the temperature of the calorimeter and water increases from 20.91 degrees C to 26.45 degrees C? The bomb has a heat capacity of 469 J/degrees . The Calorimeter contaains 792 grams of water.

*December 8, 2010*

**Chemistry**

Calculate the weight percent of water in NiSO4 6H2O, how to calculate it?

*December 8, 2010*

**alg 2**

to find 'x' you add 243 to both sides so: 3x^2=243 divide both sides by 3 3x^2/3 = 243/3 x^2 = 81 then take the square root of both sides so x=9 hope that helps, be sure to plug your numbers back in to check it take 9 and plug it in for x :: 3(9)^2-243 3(81)-243 243-...

*December 8, 2010*

**Chemistry**

Calculate the weight percent of water in NiSO4 6H2O, how to calculate it?

*December 8, 2010*

**Chemistry**

Calculate the weight percent of water in NiSO4 6H2O, how to calculate it?

*December 8, 2010*

**college Chemistry**

B. because it jumps straight from 1s2 to 2p1 it has to go :: 1s2 2s2 then 2p1

*December 6, 2010*

**advice**

could you mark each verb used in bold. identify the specific tense used in parentheses. I have seen many examples of different saving plans. I planned on using these strategies in my personal life.

*December 5, 2010*

**physics**

but what if it asks how long it will take to fall?

*December 4, 2010*

**physics**

OH!! so that's where i went wrong. thanks again! ^w^

*December 4, 2010*

**physics**

so its 2*9.81*155?

*December 4, 2010*

**physics**

The single cable supporting an unoccupied elevator breaks when the elevator is at rest at the top of a 155 m high building. With what speed does the elevator hit the ground?

*December 4, 2010*

**physics**

At the instant a traffic light turns green, a car starts moving with a constant acceleration a of 4.00 m/s2. At the same instant a truck, traveling with a constant speed of 10.09 m/s, overtakes and passes the car. How far beyond the traffic light will the car overtake the truck?

*December 4, 2010*

**physics**

thank u so much!! ^w^

*December 4, 2010*

**physics**

so how would i go about finding acceleration?

*December 4, 2010*

**physics**

The airplane can take off when its airspeed (speed of the air flowing over the wing) is equal to 65 knots. What is the length of runway required for the plane to take off if there is a 21 knots head wind? The runway at the Tallahassee Regional Airport has a length of 8000 ft.

*December 4, 2010*

**Biology**

I need help making a concept map. I have to put the following words into one and i don't know where to start. Gene DNA Chromosome Mutations Protiens Central Dogma Signal Transduction Nucleus mRNA tRNA rRNA Ribosomes Autosomes Sex Chromosomes Recessive Translation ...

*December 3, 2010*

**W.H.Atwell**

Does 2Na 2H2O 2NaOH H2 shows that the total mass during a chemical reaction stays the same?

*December 1, 2010*

**12th grade English**

ok thank u anyway

*November 30, 2010*

**12th grade English**

o an thanks

*November 30, 2010*

**12th grade English**

srry its catcher in the rye

*November 30, 2010*

**12th grade English**

I need help i have to have a literary term for ch. 1,2,3,5,12,13,14,16,and 26 im having trouble figuring out how to do that so can somone help me please

*November 30, 2010*

**Chemistry**

Calculate the percent of carbon, hydrogen, nitrogen, and oxygen in this widely used pesticide, Sevin. The molecular formula is C12 H11 O2 N.

*November 23, 2010*

**Chemistry**

Calculate the percent of carbon, hydrogen, nitrogen, and oxygen in this widely used pesticide, Sevin. The molecular formula is C12 H11 O2 N.

*November 23, 2010*

**chemistry**

combustion of 0.356g of an unknown metal sample in oxygen gives 0.452g of an oxide in the form of mO2, Identify the unknown metal?

*November 23, 2010*

**Chemistry**

A gas has a volume of 4.00 at 0. What final temperature in degrees Celsius is needed to cause the volume of the gas to change to the following, if (number of moles of gas) and are not changed? 290 L

*November 23, 2010*

**chemistry**

how do you figure that out?

*November 23, 2010*

**chemistry**

What mass of Zn can be dissolved by 558 mL of 3.01M HCl?

*November 23, 2010*

**ela**

if you unscramblethe letters SATLEIVER what word do u get and it has to do with thanksgiving

*November 22, 2010*

**algebra**

The following problem has a total of six solutions each. (X^2-5x+5)^x^2-9x+2=1. Its extra credit

*November 19, 2010*

**Physics**

Find the heat necessary to change 2.5kg of water (ice) at -2 degrees C to steam at 105 degrees C. specific heat ice= 2060 specific heat water= 4180 specific heat steam= 2020 heat of fusion= 3.34X10^5 heat of vaporization= 2.26X10^6

*November 18, 2010*

**Physics**

How much heat must be added to 3kg of liquid water at 25 degrees C to change it into steam at 120 degrees C?

*November 18, 2010*

**physics**

a banana with a temperature of 17 degrees C (specific heat of banana= 3520j/kgK) and a a mass of 250g is placed in a bowl of milk with a temperature of 8 degrees C and a mass of 350g (specific heat of milk= 4200 J/kgK). no heat is lost to the bowl or the air as the banana and ...

*November 18, 2010*

**Physics**

lead melts at 328 degrees C. lead has a heat of fusion of 2.04X10^4 J/kg and a specific heat of 130 J/kgK. how much heat must be removed from 0.50 kg of molten lead (liquid) at 328 degrees C to make it all a solid chunk at 300 degrees C?

*November 18, 2010*

**5th grade science**

blank a type of material that tries to prenent the flow of thermal energy.

*November 15, 2010*