# 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

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

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.

4. ## biology

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

5. ## math

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

6. ## Math

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

7. ## 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?

8. ## 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!

9. ## home economics

what are the characteristics of dirt?

10. ## math

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

11. ## 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

12. ## science

How do animals find their shelter?

13. ## 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).

14. ## Math

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

15. ## 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?

16. ## 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)

17. ## Chemistry

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

18. ## 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

19. ## Math Help

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

20. ## Math Help

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

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)

22. ## 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?

23. ## 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

24. ## 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

25. ## 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.

26. ## 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

27. ## 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

28. ## 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

29. ## 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

30. ## 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

31. ## 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?

32. ## ECE 201

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

33. ## physics

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

34. ## english

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

35. ## 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

36. ## 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

37. ## 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

38. ## 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!

39. ## 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)?

40. ## social studies

What do people in Catalonia celebrate every April 23rd?

41. ## social studies

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

42. ## 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

43. ## world history

How has the global economy changed after the Cold War?

44. ## 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

45. ## 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?

46. ## 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

47. ## 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

48. ## 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

49. ## 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

50. ## ap world history

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

51. ## ap world history

how did wheat impact the Americas?

52. ## ap world history

where did wine originate?

53. ## world history

to what places did wine spread?

54. ## 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"?

55. ## 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!!

56. ## Fluid Imbalances

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

57. ## 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

58. ## 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

59. ## 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

60. ## 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

61. ## 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.

62. ## 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?

63. ## chemistry help plz

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

64. ## 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.

65. ## CHEMISTRY

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

66. ## 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?

67. ## 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=

68. ## 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.

69. ## 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.

70. ## 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.

71. ## 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?

72. ## 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?

73. ## 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

74. ## Math

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

75. ## Match

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

76. ## 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?

77. ## 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

78. ## 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?

79. ## 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?

80. ## CHEM

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

81. ## 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?

82. ## Chem

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

83. ## 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.

84. ## 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

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

86. ## 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

87. ## 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

88. ## 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

89. ## Physics

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

x

91. ## 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.

92. ## 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

93. ## 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?

94. ## 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

95. ## 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!

96. ## 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

97. ## english

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

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

99. ## 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