# Posts by Ellen

Total # Posts: 227

Math
17 cents per piece

science

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?

science
does noone know

science

science
urgent

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 ...

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!

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) ...

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.

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?

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.

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.

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 ...

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

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

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.

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

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

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 ...

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 ...

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?

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 ...

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 ...

Chemistry
sorry. didn't mean to post twice

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 ...

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 ...

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 ...

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)+...

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)

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 ...

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?

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

chemistry
I put in the wrong numbers for the second part.

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.

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 ...

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.

chemistry
what is the pH of 0.15 M NaF?

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?

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?

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 ________...

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?

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 ...

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?

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?

CH102
nevermind! figured it out

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?

Chemistry
i tried that but it says its wrong

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

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

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, ...

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 ...

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...

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

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.

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?

Chopsticks
3x^2-8x+1=0

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...

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

7th pre-algebra
I need help understanding how to slove two step equations. Example -10 - k=-36

math
This is incorrect

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!

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.

Orientalism
What are the three aspects of Orientalism

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.

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?

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?

Chemistry
Thank you for helping me with this.

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...

algebra
yes. thank you very much

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

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?"

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?"

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?

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?

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

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??

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"...

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.

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

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

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

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

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

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!

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. ...

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. ...

Science
How does the ozone effect the wind patterns

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

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

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?

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

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...

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...

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...

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?

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!

Pre-Algebra
Thank you!

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??