# Posts by Ellen

Total # Posts: 225

**science**

lena carried out an investigation to find the energy content in bacon rind she lit the bacon rind with a bunsen burner and held it beneath a test tube of water she stirred the water and recorded it temperature! why did lena stir before recording the temperature?

*March 19, 2011*

**science**

does noone know

*March 18, 2011*

**science**

please help

*March 18, 2011*

**science**

urgent

*March 18, 2011*

**science**

the list below shows three ways in which metals can react. a) strongly heat the metal in the air. b)add small pieces of the metal to cold water. c)add small pieces of the metal to dilute acid. in each case choose a b or c calcium oxide hydrogen (using zinc) magnesium chloride ...

*March 18, 2011*

**Physics**

My teacher didn't specify if 9.821 m/s^2 is the value of the North Pole. We don't have class this week because of Spring Break and it's due the morning we get back, so I can't ask him any questions. But I got C through F now, thank you!

*March 4, 2011*

**Physics**

Consider a pendulum of length 4.557 m. The acceleration of gravity is 9.832 m/s2 . a) What is its period at the North Pole? Answer in units of s. b) What is its frequency? Answer in units of Hz. c) What is its period in Chicago, where g = 9.803 m/s2? Answer in units of s. d) ...

*March 4, 2011*

**Physics**

A trapeze artist swings in simple harmonic motion with a period of 3.2 s. The acceleration of gravity is 9.81 m/s2 . Calculate the length of the cables supporting the trapeze. Answer in units of m.

*March 4, 2011*

**Physics**

A mass of 0.38 kg is attached to a spring and is set into vibration with a period of 0.22 s. What is the spring constant of the spring?

*March 4, 2011*

**math (calculus)**

A cap of a sphere is generated by rotating the region about the y-axis. Determine the volume of this cap when the radius of the sphere is 5 inches and the height of the cap is 1 inch.

*February 13, 2011*

**math (calculus)**

A cap of a sphere is generated by rotating the region about the y-axis. Determine the volume of this cap when the radius of the sphere is 5 inches and the height of the cap is 1 inch.

*February 13, 2011*

**Physics**

The hoover dam produces 2x10 to the 9 W of electricity. It is composed of 7x10 to the 9 kg of concrete. To produce 1 kg of concrete requires 1 MJ of energy. How much energy did it take to produce the dam? How long was the "energy payback time" for the dam? The area ...

*February 2, 2011*

**Physics**

the relationship between rotational speed and net force is direct right? and also can u say why it is direct

*January 31, 2011*

**physical science 2**

It takes 6 seconds for a stone dropped from rest to the bottom of a well,what is its final speed A; 6 meters/second B: 30 meters/seconds C: 36 meters/seconds D: 60 METERS/SECONDS A is incrrect

*January 29, 2011*

**Physical Science 2**

Ten seconds after starting from rest,a freely falling object will have a speed of about______ rn/s A: 10 B: 50 C: 100 D: 120 I know that the answer A is not correct.

*January 29, 2011*

**physical science 2**

A block is dragged at constant velocity in a straight line path across a level surface by force of 6 N. What is the friction between the black and the surface? a: 6 N B: less than 6 N C: More than 6N d: ZERO

*January 29, 2011*

**physical science 2**

the force required to maintain an object at a constant velocity in free space is equal to: b: the mass of the object. c: the force required to stop it. d zero

*January 29, 2011*

**physical science**

A kg ball of lead rests next to a 10 kg rock. which statement below is true:a:the lead ball and rock have the same amount of inertia,b:if the lead ball and the rock fell from the same height in a vacuum, the rock would hit the ground first because it is less massive,c: on the ...

*January 29, 2011*

**physical science**

a car traveling in a lage circlepasses by a motorcycle that is trveling in a straight line north to south.both of their speedometers read 10m/s.which statement is true; a: the car and motorcycle have the same speed ,but different velocities,b:the car and motorcycle have the ...

*January 29, 2011*

**physics**

The centers of a 6.0 lead ball and a 70 lead ball are separated by 8.0 . What gravitational force does each exert on the other? What is the ratio of this gravitational force to the weight of the 70 ball?

*October 31, 2010*

**Chemistry**

A calorimeter contains 21.0 mL of water at 14.0 degreesC. When 1.90 g of X (a substance with a molar mass of 70.0 g/mol) is added, it dissolves via the reaction X(s)+H_2O(l)reacts to make X(aq) and the temperature of the solution increases to 28.5degreesC. Calculate the ...

*October 22, 2010*

**Chemistry**

80.0 mL of water is initially at room temperature (22degrees C). A chilled steel rod at 2 degrees C is placed in the water. If the final temperature of the system is 21.2 degrees C, what is the mass of the steel bar? Specific heat of water = 4.18J/g(degreesC) Specific heat of ...

*October 22, 2010*

**Chemistry**

sorry. didn't mean to post twice

*October 10, 2010*

**Chemistry**

Helium-oxygen mixtures are used by divers to avoid the bends and are used in medicine to treat some respiratory ailments. What percent (by moles) of Helium is present in a helium-oxygen mixture having a density of 0.538 g/L at 25 degrees C and 721 mmHg? Express your answer ...

*October 10, 2010*

**Chemistry**

Helium-oxygen mixtures are used by divers to avoid the bends and are used in medicine to treat some respiratory ailments. What percent (by moles) of helium is present in a helium-oxygen mixture having a density of 0.538 g/L at 25 degrees C and 721mmHg? Express your answer ...

*October 10, 2010*

**Chemistry**

Typically, when a person coughs, he or she first inhales about 2.50 L of air at 1.00atm and 25 degreesC. The epiglottis and the vocal cords then shut, trapping the air in the lungs, where it is warmed to 37 degrees C and compressed to a volume of about 1.70L by the action of ...

*October 10, 2010*

**Chemistry**

Redox titrations are used to determine the amounts of oxidizing and reducing agents in solution. For example, a solution of hydrogen peroxide,H2O2, can be titrated against a solution of potassium permanganate, KMnO4. The following equation represents the reaction: 2KMnO4(aq)+...

*October 3, 2010*

**Chemistry**

A volume of 50.0 mL of aqueous potassium hydroxide was titrated against a standard solution of sulfuric acid. What was the molarity of the KOH solution if 19.2 mL of 1.50 M H2SO4 was needed? The equation is 2KOH(aq) +H2SO4(aq)-» K2SO4(aq)+2H2O(l)

*October 3, 2010*

**physics**

A duck has a mass of 2.3 kg. As the duck paddles, a force of 0.07 N acts on it in a direction due east. In addition, the current of the water exerts a force of 0.26 N in a direction of 48° south of east. When these forces begin to act, the velocity of the duck is 0.15 m/s ...

*September 23, 2010*

**math**

i have 3 pints oil and 12 gallons of gas,each lawn mower uses 0.5 pints of oil and 1.5 gallons of gas. How many days can she mow lawns?

*September 16, 2010*

**chemistry**

Thank you! Now I am having problems with part e.

*July 29, 2010*

**chemistry**

I put in the wrong numbers for the second part.

*July 29, 2010*

**chemistry**

I can't figure out how to get the initial pH. Also, when I tried part B I used 21.0 mL*.100M=XmL*0.130 and it wasn't the correct answer.

*July 29, 2010*

**chemistry**

Consider the titration of 21.0 mL sample of 0.110 M HC2H3O2 with 0.130 M NaOH. what is the initial pH? what is the volume of added base required to reach equivalance point? what is the pH at 5.00 mL of added base? pH at one half o the equivalence point? pH at the equivalence ...

*July 29, 2010*

**chemistry**

Calculate the pH of the solution that results from the mixture. 170 mL of 0.12 M C2H5NH2 with 285.0 mL of 0.22 M C2H5NH3Cl.

*July 28, 2010*

**chemistry**

what is the pH of 0.15 M NaF?

*July 28, 2010*

**chemistry**

If 5.05mL of 0.1000 M NaOH solution is needed to just neutralize excess acid after 20.00 mL of HCl was added to 1.00 g of an antacid, how many moles of acid can the antacid counteract per gram?

*July 27, 2010*

**chemistry**

If 5.00 mL of HCl require 4.03 mL of 0.9581 M NaOH to just consume the HCl, what is the concentration of the HCl?

*July 25, 2010*

**chemistry**

need help with these problems: The concentration of glucose in blood is usually about 0.10% (w/v). If 7.0 L of blood are in an average man, how many grams of glucose are in his blood? To obtain the solute for 118 g of a 19.2% (w/w) solution of sugar we would weigh out ________...

*July 20, 2010*

**chemistry**

need help setting this problem up: The heat of fusion of water is 335 J/g. How much heat would be required to melt 10.4 g of ice?

*July 20, 2010*

**Chemistry**

The following reaction was monitored as a function of time: AB--->A+B A plot of 1/[AB] versus time yields a straight line with slope 5.2×10−2 . If the initial concentration of is 0.240M , and the reaction mixture initially contains no products, what are the ...

*July 18, 2010*

**chemistry**

The following reaction was monitored as a function of time: AB--->A +B A plot of 1/[AB] versus time yields a straight line with slope 5.2 x 10^-2 M*s. What is the value of the rate constant (k) for this reaction at this temperature?

*July 17, 2010*

**ch102**

The rate constant of a reaction at 30 was measured to be 5.7×10^-2. If the frequency factor is 1.2 x10^13 /s what is the activation barrier?

*July 16, 2010*

**CH102**

nevermind! figured it out

*July 16, 2010*

**CH102**

If a temperature increase from 18.0 to 34.0 triples the rate constant for a reaction, what is the value of the activation barrier for the reaction?

*July 16, 2010*

**Chemistry**

i tried that but it says its wrong

*April 16, 2010*

**Chemistry**

An air sample contains 0.038% CO2. If the total pressure is 764 mm Hg , what is the partial pressure of CO2?

*April 16, 2010*

**Physics**

thank you so so so much. the answer is .3626

*March 24, 2010*

**Physics**

A hollow plastic spherical bobber of mass 0.005 kg and volume of 50 cm3 floats on the surface of a lake supporting a submersed fishhook and a bait with a combined mass of 0.01 kg and a combined volume of 2 cm3. The density of water is 0.001 kg/cm3. If a fish grabs the bait, ...

*March 24, 2010*

**ENVIRONMENTAL SCIENCE**

A viewpoint expressed in the video material emphasizes the idea that every type of species has its meaning and purpose, and is important part of biodiversity. Unique characteristics of different species contain the secret of harmony in the world, benefiting from each other by ...

*January 19, 2010*

**Algebra/story problem**

Can someone help me work this problem please? The equation y= -1777x+27,153 can be used to predict the number of gun deaths in the United States x years after 2000, that is x=0 corresponds to 2000, x=2 corresponds to 2002, x=4 corresponds to 2004, and so on. Predict the number...

*January 7, 2010*

**Marketing**

What arguments can you make against the common assumption that marketers only worry about advertising?

*December 1, 2009*

**General Physics**

A 0.40 - kg object connected to light spring with a force constant of 19.6 N/m oscillates on a frictionless horizontal surface. If the spring is released from rest, determine the maximum speed of the object.

*November 12, 2009*

**math**

when y=-sinx and y=sin2x - sinx are added together and graphed, why do the maximum values of two sin functions occur where they do?

*October 13, 2009*

**Chopsticks**

3x^2-8x+1=0

*August 31, 2009*

**literary**

I am writing my father's obituary - he passed away unexpectedly on Monday. He was from a very small town and always quoted verse that ended with "And when I go (return) home, I am a boy again" Walt Whitman. Dylan Thomas. Please. Please. I have a deadline tomorrow...

*June 24, 2009*

**algebra**

Graph the equation using the slope and the y- intercept y= 8/5x+5

*June 7, 2009*

**7th pre-algebra**

I need help understanding how to slove two step equations. Example -10 - k=-36

*May 11, 2009*

**math**

This is incorrect

*April 9, 2009*

**art -year8-writeacher**

thankyou for finding those websites for me they are a great help. i looked at those myself but i wasn`t sure if they were right. thanks again!

*April 3, 2009*

**art -year8**

i need to design a renaissance outfit for art. please could someone help me find some websites that show some outfits that can help me. thankyou.

*April 3, 2009*

**Orientalism**

What are the three aspects of Orientalism

*March 25, 2009*

**Reiny! Reiny! Reiny!**

1. Oanh walked from her home to the grocery store at 3 mi/h and jogged home at 6 mi/h. Her total round trip was 15 minutes (1/4h). How far from Oanh's home is the grocery store? (use an equation to solve this) Help, I am totally clueless on this.

*February 5, 2009*

**PLEASE HELP ME!**

Rewrite each polynomial as the product of two binomials. 1. y^2 + 6y + 9 2. 25x^2 - 10x + 1 3. 36 - y^2 I don't understand how to do these problems, especially what the direction is telling me to do. Someone help me please?

*January 16, 2009*

**Algerba 1**

Rewrite each polynomial as the product of two binomials. 1. y^2 + 6y + 9 2. 25x^2 - 10x + 1 3. 36 - y^2 I don't understand how to do these problems, especially what the direction is telling me to do. Someone help me please?

*January 16, 2009*

**Chemistry**

Thank you for helping me with this.

*December 16, 2008*

**Chemistry**

We did a flame testing lab today with the following metal ions: Sodium, Na^+1 Barium, Ba ^2+ Calcium, Ca ^2+ Copper, Cu ^2+ Potassium, K ^+1 Strontium, Sr ^2+ Lithium, Li ^+1 The question asks to explain the effect of the nitrate ion solution on the color emission. Please help...

*December 16, 2008*

**algebra**

yes. thank you very much

*December 1, 2008*

**algebra**

how would you go about solving this problem? a x 2b/6 x 4/5a

*December 1, 2008*

**algebra**

so would i do this: 82.1 - 86 = -3.9 now that i have the -3.9 would that be the final answer to the question "what is the deviation from the mean that day?"

*November 9, 2008*

**algebra**

so would i do this: 82.1 - 86 = -3.9 now that i have the -3.9 would that be the final answer to the question "what is the deviation from the mean that day?"

*November 9, 2008*

**algebra**

How would i go about answereing this question? The mean temperature in new york one summer was 86 degrees. if the temperature on july 22 of that summer was 82.1 degrees, what was the deviation from the mean that day?

*November 9, 2008*

**math**

How would i go about answereing this question? The mean temperature in new york one summer was 86 degrees. if the temperature on july 22 of that summer was 82.1 degrees, what was the deviation from the mean that day?

*November 9, 2008*

**Writing**

thanks, do you have any ideas that interest you that would be about 3,000 words

*November 8, 2008*

**Writing**

thank you very much. my main interest was the white house. do you have any topics with why question that i could do for that??

*November 8, 2008*

**Writing**

i have to do a research paper for journalism class. It has to be something that has to do with washington, d.c. but the topic cant be too generalo. it has to be something specific that i will be able to write 1,500 to 3,00 words. Also, the topic has to answer a "WHY"...

*November 8, 2008*

**physics**

A pendulum consists of an object of mass 1.07 kg that hangs at the end of a massless bar, a distance 1.14 m from the pivot point. Calculate the magnitude of the torque due to gravity about the pivot point if the bar makes an angle of 22° with the vertical.

*October 9, 2008*

**physics**

A 4422.0 kg truck is parked on a 10.8° slope. What is the friction force on the truck?

*October 9, 2008*

**physics**

A woman has a mass of 64.2 kg. What is her weight on earth?

*October 9, 2008*

**Algebra**

Solve sytems of equations for 7x-3y=31 and y-5=3x I need to find what x and y equal. thanks!

*April 20, 2008*

**Algebra**

Explicitly explain how to tell an answer is correct when solvingi systems of equations. -thanks so much!

*April 3, 2008*

**math**

find distance from (-4,2) to (5,14)

*March 23, 2008*

**Physical Science**

If you poked 3 holes in a vertical line in a bottle filled with water, which hole will spurt water the furthest? Why? -thanks so much for your help!

*March 17, 2008*

**finance and accounting**

Account Word Problems like this I seem not to get the concept , please give me an exam as how to figure out this problem. 1. The liabilities of Acosta Corporation equal one-third of the total assets. And stockholders equity is $160,000. What is the amount of the liabilities. ...

*March 4, 2008*

**finance and accounting**

Account Word Problems like this I seem not to get the concept , please give me an exam as how to figure out this problem. 1. The liabilities of Acosta Corporation equal one-third of the total assets. And stockholders equity is $160,000. What is the amount of the liabilities. ...

*March 3, 2008*

**Science**

How does the ozone effect the wind patterns

*January 22, 2008*

**US history**

Hi! i am wondering if you can explain amendmant 7 in more depth. Thanks!

*January 19, 2008*

**Algebra**

What is the differance between a discrete graph and a continuous graph? Thanks so much!

*January 16, 2008*

**Pre**

A) List two examples of pairs of numbers that share a common factor. B) List a variable pair with a common factor. C) Why do u think ab+ac is called "simplified form"? I don't really what they are asking me to do... ummmm, anyone help me?

*January 7, 2008*

**Just Wondering**

Whats Christmas anyways? Like, how did it become a true holiday? What is the story behind it?

*December 24, 2007*

**Math**

You were busy working on a problem using 4 big squares, 8 rectangles, and 8 small squares. Your partner accidentally knocked some algebra tiles off the your desk. You now have 1 big square, 3 rectangles, and 5 small squares on your desk. Write and algebraic equation that shows...

*December 10, 2007*

**Pre-Algebra**

You were busy working on a problem using 4 big squares, 8 rectangles, and 8 small squares. Your partner accidentally knocked some algebra tiles off the your desk. You now have 1 big square, 3 rectangles, and 5 small squares on your desk. Write and algebraic equation that shows...

*December 10, 2007*

**Pre-Algebra**

You were busy working on a problem using 4 big squares, 8 rectangles, and 8 small squares. Your partner accidentally knocked some algebra tiles off the your desk. You now have 1 big square, 3 rectangles, and 5 small squares on your desk. Write and algebraic equation that shows...

*December 10, 2007*

**French**

so, how do u really say this quote in french? "You are in love when suddenly reality is in your dreams, and you cannot sleep anymore." help?

*December 4, 2007*

**Pre-Algebra**

What does P-E-M-D-A-S mean? I know they are the orders of operation, but I forgot what each letter stand for??? HELP!

*November 28, 2007*

**Pre-Algebra**

Thank you!

*November 28, 2007*

**Pre-Algebra**

okay so the decimal is 0.001 and I need to convert it to a fraction and a precent? how do I do that??

*November 28, 2007*

**Pre-Algebra please help me!!**

OMG! thank you sooo much! genius! it works by the way!!!

*November 26, 2007*

**Pre-Algebra please help me!!**

X- 0 1 2 3 4 5 6 Y- -7 -4 -1 2 5 8 11 this is a x and y table I need to find out wat the rule is to get y. So the equation would start out like: Y=?????? wat do u need to do with x to get y? and I need help badly! so please!

*November 26, 2007*

**algebra**

(p+3)(p-4)(p-3)(p+4)

*November 25, 2007*