Lena

Newest questions and responses by Lena

  1. Physics

    Your vertical spring accelerometer has a 200 g mass hanging from it. You climb aboard the roller coaster and watch the accelerometer read 0.4 g for 3 seconds while descending the first peak and then change to 1.5 g for 2 seconds while climbing the second

    asked on May 28, 2018

  2. world history

    how did the cold war influence events in the postwar period I can't find this in my textbook. could someone explain please

    asked on March 15, 2018

  3. biology

    would you consider that eukaryotic cells got rid of their cell wall to benefit as a heterotroph? They must of had a cell wall to begin with because all cells come from prokaryotic cells.

    asked on November 1, 2017

  4. biology

    did cells loose their cell wall due to evolution or did they never have a cell wall to begin with? pls explain

    asked on October 31, 2017

  5. math

    Using the quadratic formula; I have to solve 8(a-squared)-a+2=0 a=8, b=-1, c=2

    asked on June 14, 2017

  7. Math

    Compare partial products and regrouping. Describe how the methods are alike and different. ♡♡♡♡?????????

    asked on October 27, 2016

  8. Math

    Kurt cut pizzas into wedges measuring 40 degrees. If each person eats one piece of pizza, how many people could he feed with two whole pizzas?

    asked on June 6, 2016

  9. Math (Rounding #s)

    How would I round 0.598958333 to the thousandths? Would it be 0.6000 or 0.5990? Also, could you please tell me why the answer is what it is? If I had something like, 0.55998, as in two 9s in the row, what would I do then? Thank you!

    asked on April 4, 2016

  10. home economics

    what are the characteristics of dirt?

    asked on February 15, 2016

  11. math

    What is the perimeter of 4 feet wide and 9 feet long?????

    asked on February 10, 2016

  12. math

    Scientists are conducting an experiment with a gas in a sealed container. The mass of the gas is measured, and the scientists realize that the gas is leaking over time in a linear way. Six minutes since the experiment started, the gas had a mass of 144

    asked on February 3, 2016

  13. science

    How do animals find their shelter?

    asked on January 21, 2016

  14. Math

    Using the distance function s(t) = t2 + 4t + 30, "s" is in feet and "t" is in seconds, find the velocity function, v(t), and acceleration function, a(t).

    asked on December 19, 2015

  15. Math

    I am a product.One of my factors is 7.The sum of my factors equals 11.What number am I?

    asked on November 17, 2015

  16. Math

    I am a number that is four times the product of 2 and 3.One of my factors is 4.What is my other factor?

    asked on November 17, 2015

  18. Math Homework

    Directions: Find the fourth-order derivative. 1.) f''(x)=7x^5/2, f(^iv)(x) 2.) f''(x)=8x^7/5, f(^iv)(x)

    asked on October 31, 2015

  19. Chemistry

    Why does the temperature in exothermic reactions increase, reach a maximum, and then decrease?

    asked on October 19, 2015

  20. Math (ASAP)

    I really need help with this. Thank you! Directions: Using the limit process, find the limit of the following function below. f(x) = 2 – x^2

    asked on October 8, 2015

  21. Math Help

    Directions: Using the limit process, find the limit of the following function below. f(x) = 2 – x^2

    asked on October 8, 2015

  22. Math Help

    Directions: Using the limit process, find the limit of the following function below. f(x) = 2 – x^2

    asked on October 8, 2015

  23. Madison

    Elliot put 7 cups of tea into the pitcher shown. How many more cups of tea does he need to fill the pitcher? (1 quart = 4 cups)

    asked on March 26, 2015

  24. physical

    1.What kind of information is indicated by the graph of the acceleration due to gravity versus ball¡¯s mass if the slope of the curve is zero?

    asked on March 16, 2015

  25. Math

    Beginning at age 35, Ms. Trinh invests $4000 each year into an IRA account until she retires. When she retires she plans to withdraw equal amounts each year that will deplete the account when she is 80. Find the annual amounts she will receive for each of

    asked on March 13, 2015

  26. Physic

    The concepts in this problem are similar to those in Multiple-Concept Example 4, except that the force doing the work in this problem is the tension in the cable. A rescue helicopter lifts a 75.4-kg person straight up by means of a cable. The person has an

    asked on March 5, 2015

  27. Physic

    A 16-kg sled is being pulled along the horizontal snow-covered ground by a horizontal force of 27 N. Starting from rest, the sled attains a speed of 2.2 m/s in 9.6 m. Find the coefficient of kinetic friction between the runners of the sled and the snow.

    asked on March 5, 2015

  29. Physic

    A 287-kg crate is being pushed across a horizontal floor by a force P that makes an angle of 25.6 ° below the horizontal. The coefficient of kinetic friction is 0.236. What should be the magnitude of P, so that the net work done by it and the kinetic

    asked on March 5, 2015

  30. Physic

    A person pulls a toboggan for a distance of 43.1 m along the snow with a rope directed 33.3 ° above the snow. The tension in the rope is 109 N. (a) How much work is done on the toboggan by the tension force? (b) How much work is done if the same tension

    asked on March 5, 2015

  31. Physic

    A person pushes a 13.7-kg shopping cart at a constant velocity for a distance of 16.3 m on a flat horizontal surface. She pushes in a direction 22.2 ° below the horizontal. A 48.7-N frictional force opposes the motion of the cart. (a) What is the

    asked on March 5, 2015

  32. Physic

    You are moving into an apartment and take the elevator to the 6th floor. Suppose your weight is 640 N and that of your belongings is 940 N. (a) Determine the work done by the elevator in lifting you and your belongings up to the 6th floor (15.2 m) at a

    asked on March 5, 2015

  33. Chemistry

    In an experiment, you dissolve 0.30 g of KHP (MM = 204.22 g/mol) in 20 mL of DI water and titrate the sample with 0.10 M NaOH. Calculate the volume (to the nearest mL) of NaOH required to reach the equivalence point. IS it a) 3 b)15 c)20 d)30 e)100 I have

    asked on January 8, 2015

  34. MATH

    SASHA AND FRANCISCO WERE SELLING LEMONADE FOR $.25 PER HALF CUP AND $.50 PER FULL CUP. AT THE END OF THE DAY THEY HAD COLLECTED $15 AND HAD USED 37 CUPS. HOW MANY FULL CUPS AND HOW MANY HALF CUPS DID THEY SELL?

    asked on September 30, 2014

  35. ECE 201

    Why is it important for teachers to understand students’ culture and backgrounds in an effort to address challenging behavior?

    asked on September 25, 2014

  36. physics

    if the diamter of a human hair is (50*10^-6 m) estimate the volume of hair on your head

    asked on September 13, 2014

  37. english

    what genre is Black Ships Before Troy ~ by Rosemary Sutcliff?

    asked on September 1, 2014

  38. Physics

    A 4.5kg box slides down a 4.1-m -high frictionless hill, starting from rest, across a 1.7-m -wide horizontal surface, then hits a horizontal spring with spring constant 490N/m . The other end of the spring is anchored against a wall. The ground under the

    asked on June 8, 2014

  40. Physics

    A horizontal spring with spring constant 110N/m is compressed 16cm and used to launch a 2.8kg box across a frictionless, horizontal surface. After the box travels some distance, the surface becomes rough. The coefficient of kinetic friction of the box on

    asked on June 8, 2014

  41. Workplace Skills

    We're supposed to read over the following scenario and provide advice for AJ: AJ has a job that he really likes and pays well, but he is worried he is about to be terminated. He doesn't want to quit his job and give up his excellent pay, but he knows that

    asked on May 25, 2014

  42. Physics

    (637) A cyclist is riding on a horizontal frozen meadow. He is turning so that he is tilted at an angle of 60°. Radius of curvature of the bend is 100m. What is the maximum speed of the cyclist? Thank you for your time!

    asked on May 25, 2014

  43. Physics

    (595)Vinyl record spinning at 45rpm. What is the frequency of rotation (in Hz)? What is the orbital time of the vinyl record (in seconds)?

    asked on May 25, 2014

  44. social studies

    What do people in Catalonia celebrate every April 23rd?

    asked on April 23, 2014

  45. social studies

    What major land form and body of water cover much of northern south america?

    asked on April 23, 2014

  46. Physics

    The inner and outer surfaces of a cell membrane carry a negative and positive charge, respectively. Because of these charges, a potential difference of about 0.070 V exists across the membrane. The thickness of the membrane is 0.000000008 m. What is the

    asked on April 19, 2014

  47. world history

    How has the global economy changed after the Cold War?

    asked on April 19, 2014

  48. world history

    Which African independence movement is most similar to the movement in Kenya? I'm thinking the one in Haiti but I'm not sure

    asked on April 16, 2014

  49. Chemistry

    what is the pH and pOH of a solution made by adding water to 15 grams of HCl until the volume of the solution is 2500mL?

    asked on April 5, 2014

  51. Chemistry

    what volume of concentrated 18M H2SO4 is required to prepare 250mL of a 6.0M solution? how would you solve this problem? i know it has something to do with the molarity formula but no idea how to apply it

    asked on March 4, 2014

  52. Chemistry Help

    1.) Calculate the number of atoms in 2.58 mol antimony. 2.) Determine the mass of 1.45 mol FePO4. 3.) Calculate the number of mol in 6.75 g of NaCl. 4.) What is the volume, in liters, of 2.54 mol methane (CH4) gas?. 5.) What is the percent composition of

    asked on February 10, 2014

  53. physics

    a 1.2 kg cart slides eastward down a frictionless ramp from a height of 1.8 m and then onto a horizontal surface where it has a head-on elastic collision with a stationary 2.0 kg cart cushioned by an ideal Hooke's law spring. the maximum compression of the

    asked on November 18, 2013

  54. Physics

    In a demonstration in physics class, a 1.2 kg dynamics cart starts from rest at the top of a ramp. the ramp is 2.4 m above the ground. the cart then rolls down to the bottom of the ramp, where it collides with a stationary 1.4 kg dynamics cart. Assume that

    asked on November 18, 2013

  55. ap world history

    which region of the world benefited more from the columbian exchange?

    asked on September 22, 2013

  56. ap world history

    how did wheat impact the Americas?

    asked on September 22, 2013

  57. ap world history

    where did wine originate?

    asked on September 2, 2013

  58. world history

    to what places did wine spread?

    asked on August 30, 2013

  59. world history

    1. How does the story of Coca-Cola relate to the rise of capitalism and entrepreneurship in the 19th and early 20th c? 2. what is the "iron curtain"?

    asked on August 29, 2013

  60. CHEM HELP!!!

    The solubility of AgCl(s) in water at 25 C is 1.33x10^-5 M and its deltaH of solution is 65.7 kJ/mol . What is its solubility at 60.1 C ? Please explain how to solve for this!!

    asked on March 22, 2013

  62. Fluid Imbalances

    Why would a person who's blood gasses indicate metabolic acidosis be at risk for hyperkalemia?

    asked on March 3, 2013

  63. English - The Lovely Bones

    I asked this question yesterday but no one has answered thus far so I thought I'd try asking again: If anyone has read The Lovely Bones novel could you please explain 2 things to me. 1) Is Ruth Connors able to see the dead? When she moves to NYC she writes

    asked on February 25, 2013

  64. The Lovely Bones

    If anyone has read this novel could you please explain 2 things to me. 1) Is Ruth Connors able to see the dead? Like when she moves to NYC she writes about all the murdered women she finds. How does she go about doing that? Can see she Susie too? 2) How is

    asked on February 24, 2013

  65. Patho - Hyperkalemia and Heart Attacks

    Could someone please explain why an increase in potassium would cause a decrease in HR? I need someone to really dumb it down for me so I can fully understand. i was thinking that more Ka+ would increase the HR but in my lesson, it said it would slow down

    asked on February 22, 2013

  66. English - APA

    I'm writing a book review in APA and I need to cite a quote. Would it be similar to an essay where I would do the following: (Author's last name, date of publication, page number) (Brown, 1999, p. 75) Do I need to include chapters, as well? The novel I'm

    asked on February 13, 2013

  67. Biochemistry

    The Go’ value for the hydrolysis of glucose-6-phosphate is -13.8 kJ/mol. Assuming a concentration of 4 mM for this molecule, what would the phosphate concentration be at equilibrium (G = 0). Remember to convert kJ to J.

    asked on February 11, 2013

  68. stat

    if the heights of men follow a normal distribution, and 99.7% fall between 5" and 7" what is the estimate standard deviation of the height?

    asked on February 2, 2013

  69. chemistry help plz

    OH-OH-benzene ring-CH=CH-NH2 is anyone knows the name of this compound?

    asked on January 14, 2013

  70. chemistry

    (a) What is the pH of 50 mL of a 0.2M glycolic acid aqueous solution after adding 5 mL of 0.25 M KOH? The pKa of glycolic acis is 3.83 at 25 ∘C.

    asked on January 11, 2013

  71. CHEMISTRY

    (c) Calculate the degree of polymerization n of polystyrene with a molecular weight of 3.091×106 g/mol.

    asked on January 5, 2013

  73. chemistry

    (c) What is the value of the degree of polymerization n of isotactic PB with a molecular weight of 3.091×105 g/mol?

    asked on January 5, 2013

  74. chemistry help plz

    what are the values of a,b,c and d in the balanced chemical equation aFe^2+(aq)+bAl(s)=cFe(s)+dAl^3+(aq) where a,b,c and d are the lowest possible whole numbers? a= b= c= d=

    asked on January 4, 2013

  75. chemistry

    (a) Cadmium telluride (CdTe) is a semiconductor witha band gap, Eg, of 1.45 eV. Calculate the value of the absorption edge of this material. Express your answer in meters.

    asked on December 14, 2012

  76. chemistry

    Show that a conventional x-ray generator is incapable of generating x-rays of wavelength as low as 10-11m. Do this by determining the identity of the target (in atomic number, Z) which would be needed to generate such x-rays.

    asked on December 14, 2012

  77. chemistry

    A latex balloon, wall thickness 3.091 x 10-4 m, contains helium at a concentration of 0.35 kg m-3. Under these conditions the total surface area of the balloon is 0.57 m2. The diffusion coefficient of He in latex at room temperature is 4.9 x 10-9 m2s-1.

    asked on December 14, 2012

  78. chemistry

    Methane (CH4) burns in oxygen to produce carbon dioxide and water vapor. The balanced equation is: CH4 + 2 O2 -> CO2 + 2 H2O What volume of carbon dioxide is produced when 3.2 L of oxygen are consumed?

    asked on December 5, 2012

  79. chemisy

    Methane (CH4) burns in oxygen to produce carbon dioxide and water vapor. The balanced equation is: CH4 + 2 O2 -> CO2 + 2 H2O What volume of carbon dioxide is produced when 3.2 L of oxygen are consumed?

    asked on December 5, 2012

  80. Determination of ASA Content of Tablets Lab Report

    Not asking for answers necesarily but I would to know how to approach each question Mass of pure acetylsalicylic acid (ASA) : .508 g Dilution Absorbance (a.u.) 2:11 .116 4:11 .259 6:11 .392 8:11 .502 10:11 .548 Mass of tablet : .380 g Absorbance read on

    asked on December 5, 2012

  81. Math

    John's Collection: 10 coins in all 2 fewer quarters than dimes 2 quarters Q = D = N =

    asked on November 12, 2012

  82. Match

    John's Collection: 10 coins in all 2 fewer quarters than dimes 2 quarters Q = D = N =

    asked on November 12, 2012

  84. Chem

    What pressure (atm) is needed to confine an ideal gas to 68.0 L after it has expanded from 44.0 L and 2.3 atm at constant temperature?

    asked on November 1, 2012

  85. CHEM

    Silicon carbide, commonly known as carborundum, is a very hard and abrasive substance. The compound is prepared by heating silicon dioxide in the presence of graphitic carbon: SiO2(s) + 2C(s) --> SiC(s) + CO2(g) How many grams of silicon carbide can be

    asked on October 18, 2012

  86. CHEMISTRY

    What element is represented by this electron ground state configuration : [Kr] 4d10 4f14 5s2 5p6 5d10 5f14 6s2 6p6 6d2 7s2 Is this really Krypton?

    asked on October 18, 2012

  87. CHEMISTRY

    What element is represented by this electron ground state configuration : [Kr] 4d10 4f14 5s2 5p6 5d10 5f14 6s2 6p6 6d2 7s2 Is this really Krypton?

    asked on October 18, 2012

  88. CHEM

    Arrange the following in order of increasing atomic radii from smallest to largest. Mg Ra Sr Be Ca Ba

    asked on October 18, 2012

  89. Chem help

    Answer the questions below for an element that has the electron configuration 1s2 2s2 2p6 3s2 3p6 4s1. A. What is the symbol for this element? B. What is the atomic number of this element? C. How many unpaired electrons does an atom of this elelemt have?

    asked on October 17, 2012

  90. Chem

    Balance the following chemical equation (put the coefficients in order) Fe + O2 + H2O → Fe(OH)

    asked on October 10, 2012

  91. Math

    Use the method of substitution to solve the linear equation! 6a=6-b 6a=5-b please help I don't get it it needs to be an ordered pair.

    asked on June 26, 2012

  92. Chemistry

    in the presence of NH3, Cu+2 forms the complex ion [Cu(NH3)4]+2. If the equilibrium concentrations of Cu+2 and [Cu(NH3)4]+2 are 1.8x10^-17M and 1.0x10^-3M respectively, in a 1.5 M NH3 solution, calculate the value for the overall formation constant of

    asked on April 3, 2012

  93. Chemistry please help

    State Dalton’s Postulates? In light of modern knowledge, what are the inaccuracies in Dalton’s Postulates? I know Dalton's postulates: -All matter consists of tiny, indivisible particles called atoms that cannot be created or destroyed -Atoms of one

    asked on February 19, 2012

  95. Science

    Which of the following is a way to improve the efficiency of a heat engine? increase Qh reduce Qh reduce Wnet increase Qc A What are the energies associated with atomic motion called? kinetic energy potential energy bond energy internal energy D A 0.10 kg

    asked on January 23, 2012

  96. Math

    Mathman couldn't resist the grooving tunes inside and paid his $5.00. He was heading straight for the punch bowl when he noticed a witch mixing it together using a solution which was 60% lizard drool and another that was only 25% lizard drool. If she

    asked on October 27, 2011

  97. Spinal Cord Injury @ T5

    I've been trying to find out what would happen to a person with complete spinal injury @ the level of T5. Is there a chart or something I could look at that would explain what would occur at each level of the spinal cord? I keep googling stuff and it keeps

    asked on September 14, 2011

  98. Physics

    For the Law of Sines state the formulas, explain them in your own words, and draw a diagram illustrating one of them.

    asked on September 11, 2011

  99. Pre-Calc

    x

    asked on September 10, 2011

  100. Pre-Calc

    Find the area of the region between the graph of y=1/x, the x-axis, and the vertical lines x = 1 and x = 4.

    asked on September 10, 2011

  101. Spinal Cord Injury @ T5

    I'm not quite understand how spinal cord injuries work. If you have a complete spinal cord injury @ T5, what does that mean in terms of what you can do? There is so much info on the cervical region of the spinal cord but I can't find much on the thoracic

    asked on September 9, 2011

  102. essay writing

    my prof said that I used next I will discuss way too much so now i'm thinking of other things to say other than discuss but I can't think of anything. this is when im stating my arguments in my introduction. any suggestions?

    asked on June 6, 2011

  103. microeconomics

    TRUE OR FALSE: 9. Assume that the Minimum Wage has increased to $14 from $10. If the total labour-income at the wage of $14 is higher than the total labour-income at the wage of $10, it means that the labour-demand with respect to wage is elastic. FALSE. I

    asked on May 31, 2011

  104. Economics

    My micro econ prof was trying to explain marginal analysis and he said the following: If your marginal happiness is 0 then you are maximally happy. I don't understand this at all. Could someone explain this to me? Thanks!

    asked on May 9, 2011

  106. Microeconomics

    I'm just confused about this one concept. My lecture notes say the following: Markets for goods + services: - firms sell - households buy Markets for Factors of Production: - Households sell - Firms buy I don't understand the "factors of production". What

    asked on May 4, 2011

  107. english

    write the possessive nouns that could replace each group of word below

    asked on April 8, 2011

  108. Business - royalty

    I'm watching shark tank and they keep going on about royalty. They'll say something along the lines of: I'll give you 500k for 30% equity and 10% royalty. I don't really understand all this business stuff but what I think is going on it that they're giving

    asked on April 3, 2011

  109. chemistry

    A studen is asket to calculate the amount of heat involved in changing 10.0 g of liquid bomine at room temperature (22.5 C) to vapor at 59.0 C. To do this, one must know specific heat (0.474 J/g*C), boiling point (59 C), and heat of vaporization (29.6

    asked on March 30, 2011

  110. Anatomical Terminology

    I often here my prof use the word proper as in "mucous glands proper". What does the word proper mean?

    asked on March 30, 2011

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