# Posts by elena

Total # Posts: 4,389

**Science**

Match the question with the correct conversion factor needed. Column A 1.What is the mass, in grams, of a single atom of carbon?: 2.What is the mass, in grams, of a single atom of iron?: 3.What is the mass, in grams, of a single molecule of water?: 4.What is the mass, in grams...

*March 7, 2017*

**Science**

What mass of sodium has the same number of atoms as 50.0 g of calcium?

*March 7, 2017*

**Math**

One fourth of a watermelon is divided among three friends what fraction of the whole watermelon will each person get

*January 25, 2017*

**Physics**

KE = W(fr)+PE KE = mv²/2 W(fr) =F •d=?N•d= ?mg•cos?•d PE=mgh=mg•d•sin? mv²/2 = ?mg•cos?•d+ mg•d•sin? d=v²/2g(?•cos?+sin?) = = 6²/2•9.8(0.25•0.241+0.259) = 3.67 m

*November 13, 2016*

**math**

In triangle wxy, wy is congruent to xy. the perimeter of triangle wxy is 76 inches. how many inches long is wx?

*June 22, 2016*

**Algebra 1**

Which statement best demonstrates why the following is a non-example of a polynomial? 33/16 - 62y^2xz-35z^1/3y^2 a. The expression has a variable raised to a negative exponent. b. The expression has a variable in the denominator of a fraction. ** c. The expression has a ...

*March 30, 2016*

**Algebra I math**

Which statement best demonstrates why the following is a non-example of a polynomial? 33/16 - 62y^2xz-35z^1/3y^2 a. The expression has a variable raised to a negative exponent. b. The expression has a variable in the denominator of a fraction. c. The expression has a negative ...

*March 30, 2016*

**Language Arts**

Un DER a SPREAD ing chest NUT tree

*March 10, 2016*

**Language Arts**

Okay, so what I think it is is: UNder A chestNUT tree, but I'm most likely wrong

*March 10, 2016*

**Language Arts**

Under a spreading chestnut tree which syllables are unstressed?

*March 10, 2016*

**Language Arts**

Which sentence has correct subject - verb agreement a) casey or robbie are coming to the movies with us b) swimming and skiing is my favorite sports c) sandwhiches or pizza both sounds good for a quick dinner** d) either your brother or his friend is making a lot of noise ...

*March 2, 2016*

**Math**

15/6 x 7/6

*January 14, 2016*

**math**

ugh i have the same question..

*December 30, 2015*

**Physics- Help!!**

1. What is the heat required in kilocalories to convert 2 kg of ice at 0°C completely into steam at 100°C? (I thought it was 2000 kilo cals but I think I'm wrong??) a. 80 Calories b. 1440 Calories c. 4186 Calories d. 540 Calories 2. A gaseous refrigerant undergoes ...

*December 20, 2015*

**Trigonometry- ??????**

If vector a= (10,10) and vector b= (4,5) then ||a+b|| ≠ ||a|| + ||b||. Explain. I don't understand what this question is exactly asking, and I'm not sure how to answer it. Please explain. Thank you very much!!!

*December 18, 2015*

**Chem**

How were each of the following cations utimately separated from the rest of the group and /or decorated? The use of equations may be helpful, where applicable. Ag+ K+ Nh4+ Al+

*November 15, 2015*

**Chem**

How were each of the following cations utimately separated from the rest of the group and /or decorated? The use of equations may be helpful, where applicable. Ag+ K+ Nh4+ Al+

*November 14, 2015*

**science**

Your Friend is correct!! I got 100% Thank you so much Your Friend!!

*October 15, 2015*

**physics 1401**

The time of the projectile motion is t=2v₀sinα/g sinα=gt/2v₀ =9.8•3/2•300=0.05 α=arcsin0.05=2.8°

*June 21, 2015*

**PHYSICS**

If ‘v’ is the speed of the bout and ‘u’ is the speed of the stream then 48/(v+u) + 48/(v-u) = 14 4/(v+u) = 3/(v-u) 48 v =7(v+u) (v-u) 4v-4u = 3v+3u => v=7u 48•7u = 7(7u+u)(7u-u) u=1 km/h

*June 20, 2015*

**PHYSICS**

5v₁+5v₂=150 25v₁-25v₂=150 v₁+v₂=30 v₁-v₂=6 v₁=18 m/s v₂ = 12 m/s

*June 20, 2015*

**Physics**

cesium-137: half-life 30.2 years, 0.3 MeV beta and 0.66 MeV gamma-ray emitter 1 Gray (Gy) = 1 joule of ionizing energy per kilogram Energy = 400 Gy•0.25 kg= 100 J 100J/0.3•10⁶•10⁻¹⁹=3.33•10¹⁵ disintegrations

*June 18, 2015*

**science**

it has been hypothesized that chloroplasts originated from photosynthetic cyanobacteria that became symbiotic inside a host cell. Which of the following observations provides the strongest evidence for this suggestion? A) microscopically, chloroplast appear similar to ...

*May 11, 2015*

**Statistics**

A criminologist is studying school violence, she selects a random sample of 25 adolescents aged 12 to 15 from a local middle school and asks the following,"How many times within the past school year have you been physically assaulted at school? She calculated the ...

*February 27, 2015*

**Statistics**

Suppose we would like to estimate the mean amount of money spent on books by students in the fall semester. We have the following data from 400 randomly selected students: mean=$205 and s=$40. Assume that the amount spent on books by students is normally distributed. Compute a...

*February 27, 2015*

**math**

are the following a function 1. y=x/2 my guess is yes 2. y=2x+1 my guess is yes 3.y=x^2 my guess is yes 4.y=mx+b im not sure

*February 3, 2015*

**math**

Does a machine that takes one quarter at a time into its input and produces one gumball in its output act like a function? my guess is YES

*February 3, 2015*

**math**

An equation is not a function if even one x value produces ____ corresponding y value(s). one less than one more than one zero for a my guess is more

*February 3, 2015*

**math**

classify the following number as rational or irrational: 4.1 My guess is Rational

*February 2, 2015*

**math**

the associative property allows you to change the order of terms in an expression. true or false my guess is True

*February 2, 2015*

**math**

okay thank you I don't know what an inverse is lol

*February 2, 2015*

**math**

I don't understand. so is it or is it not a function

*February 2, 2015*

**math**

Is y=3x^2-2 a function? my guess is NO

*February 2, 2015*

**math**

thank you!

*February 2, 2015*

**math**

Which relationship would most likely have a positive correlation? The amount of memory in computer, and the number of keys on the keyboard. The rate at which a train travels, and the time it takes for it to reach its destination. The number of tickets sold for a baseball game...

*February 2, 2015*

**Physics**

the charge on a pith ball was measured as +40 nC. if the charge on an electron is -1.6 x 10^-19, how many electrons have been added or removed from the ball?

*January 31, 2015*

**Chemistry - PLEASE HELP!!!**

A 5.0 g n2o (laughing gas) that is inside a 12 mL cylinder used used to fill up a 800 mL whipped cream container. Beforehand, the container had air in it at 760 torr atmosphere pressure at 25 degrees celsius. Then, we will add the n2o/air mix to balloon until the pressure in ...

*January 15, 2015*

**math**

Does the Commutative Property apply to this situation? I ate dinner and read a book. I got = Yes.

*January 14, 2015*

**math**

If Jim is twice as old as Jerry plus six, Jerry is three years older than Tom, and Tom is 12, how old is Jim? I got = Jim is 36

*January 14, 2015*

**Math**

if x-7=14 what is the value of x-2 Can someone help me with this. I know the answer, I just want to know how something like this is solved.

*January 8, 2015*

**earth science**

the Julian calendar is the calendar we currently use. True or false. my guess is true

*January 1, 2015*

**earth science**

one reason the moon might be a better place than earth to study the universe is there is almost no atmosphere. True or False MY guess is false

*January 1, 2015*

**earth science**

During the summer _________ in India, wet air from the Indian ocean brings heavy rain to India.

*December 30, 2014*

**earth science**

air pollution in pennsylvania causes ______ in new england because the wind blows the pollution into new England. can someone please help, I cant find this anywhere.

*December 30, 2014*

**SCIENCE**

The burning of fossil fuels cause the earth to get warmer by putting carbon dioxide in the atmosphere and the carbon dioxide traps heat. MY GUESS: TRUE

*December 22, 2014*

**EARTH SCIENCE**

Smog is the worst in.. A. Chicago B. New York C. Los Angles MY GUESS: C. LOS ANGLES

*December 22, 2014*

**Earth science**

THANKS

*December 22, 2014*

**Earth science**

TRUE OR FALSE The burning of fossil fuels cause the earth to get warmer by putting carbon dioxide in the atmosphere and the carbon dioxide traps heat. MY GUESS: TRUE Isobars help meteorologists find fronts on weather maps. MY GUESS: FALSE A CLOUD IS A COLLECTION OF WATER ...

*December 22, 2014*

**Geography**

Thank you!

*December 8, 2014*

**Geography**

I have an essay that says.. "It has been said that Eastern Europe is a political region more than a physical region. Would you agree or disagree with this statement? You must provide a solid argument for your position." since it asks me for my opinion how do I write ...

*December 8, 2014*

**Math**

the average of five numbers is 16. Suppose 10 is added to five numbers. What is the average of the six numbers?

*October 12, 2014*

**chemistry**

Use activity coefficients to find the concentration of hydrogen ions in a solution of 90.0 mM butanoic acid and 0.05 M NaCl. The ionization constant of butanoic acid is Ka = 1.52 × 10-5. Take the size of C3H7COO– to be 500 pm. How do I calculate the ionic strength ...

*October 3, 2014*

**math**

two students are playing a math game . the object of the game is to make the least possible number by arranging the given digits inside absolute value bars on a card . in the first round , each player will use the digits 3,5,and7 to fill in the card. One student arranges the ...

*September 25, 2014*

**Whats this**

middle East

*August 5, 2014*

**chemistry**

4.62kj

*June 23, 2014*

**Law**

2. http://en.wikipedia.org/wiki/Diversion_program

*June 10, 2014*

**physics**

Here, u1 = 30 km/h t = 2 s u2 = 33.6 km/h a = (u2 – u1)/t a1 = (33.6 – 30)/2 = 1.8 ms-2 Similarly, a2 = (37.2 – 33.6)/2 = 1.8 ms-2 The acceleration of the vehicle is 1.8 ms-2

*June 10, 2014*

**MATH**

B. 5/51

*June 9, 2014*

**MATH**

I think it's B. The probabilities change every time a bill is pulled out. The probability of pulling out a 1 first is 5 out of 18 which is .227 then the probability of pulling out a 10 is 6 out of 17 because you don't replace the bill. since the events are independent ...

*June 9, 2014*

**MATH**

I think it's B. The probabilities change every time a bill is pulled out. The probability of pulling out a 1 first is 5 out of 18 which is .227 then the probability of pulling out a 10 is 6 out of 17 because you don't replace the bill. since the events are independent ...

*June 9, 2014*

**business**

This site will show you what you need http://www.opengroup.org/public/arch/p4/bus_scen/bus_scen.htm

*June 8, 2014*

**algebra**

This site shows you how to find terms of the sequence http://www.math-magic.com/sequences/next_term.htm

*June 5, 2014*

**I may fail the 8th grade?**

1. Take a deep breath. 2. I may be able to help. 3. post questions on your homework here and either ms.sue will help or me. BTW HELP we wont give you the answers but we will ensure help and explanations and you will get it right

*June 5, 2014*

**Biology**

A virus is a rudimentary biosystem that has some of the aspects of a living system such as having a genome (genetic code) and the ability to adapt to its environment. A virus, however, cannot acquire and store energy and is therefore not functional outside of its hosts. ...

*June 5, 2014*

**biology**

A capsid is the protein shell of a virus. It consists of several oligomeric structural subunits made of protein called protomers. A prion is an infectious agent composed of protein in a misfolded form.

*June 5, 2014*

**Psychology**

Read this and find your answer http://www.sirc.org/publik/drinking3.html

*June 5, 2014*

**Psychology**

What may ultimately make an abnormal behavior into a genuine mental disorder is if the behavior: 1. is maladaptive (harmful to self or others) 2. causes significant social impairment 3. causes significant occupational impairment 4. causes great personal pain and emotional ...

*June 5, 2014*

**biology**

The basic difference is their components. Viruses contain both nucleic acids (DNA or RNA) and a protein coat. Viruses cause infection by inserting their genetic material in a host cell. The host cell then replicates and reads the genetic material, making new viruses that ...

*June 5, 2014*

**Algebra**

there are 56 ways

*June 5, 2014*

**Algebra**

use the 8C3.now, can u evaluate the value of 8C3 ?.nCr = n!/r!(n-r)!it is the general formula of combination. also u have know about the "factorial", like 3! = 3 * 2 * 1 = 6 8C3, in this case knowed n=8 and r=3. by using the formula above, it can be 8C3 = 8!/3!(8-3...

*June 5, 2014*

**Measurment**

To answer this question, you'll need to find the surface area of the top of the container (which is a circle), along with the surface area of the side of the container.Note that the diameter of the container is given and is 6 inches; therefore, the radius is ... what? Note...

*June 5, 2014*

**english**

I think its either A. or C. but im not sure. Maybe A

*May 28, 2014*

**english**

In "A Man Called Horse," After his wife leaves him, Yellow Robe Behaves recklessly in battle because he A. would rather die than live with the bitterness he feels as a result of his lost pride B. is trying to gain membership in the society known as the foxes C. ...

*May 28, 2014*

**english**

I think its D

*May 28, 2014*

**english**

writers portray the personalities of characters A. only through revealing the characters private thoughts. B. through plot complication. C. only if the plot is not important to the story. D. through a variety of methods.

*May 28, 2014*

**7 grade math**

Thank you @Bobpursley!!

*May 27, 2014*

**7 grade math**

Consider two types of nonlinear equations. What unique quality does each possess and how does that quality cause the graph's unique shape? Name two unique examples of these shapes in real-world situations.

*May 27, 2014*

**URGENT Physics help**

F=kq₁q₂/r² q₂= F r²/kq₁= 7.2•10⁻²/9•10⁹•4•10⁻⁶= =2•10⁻⁶ C = 2μC Cpper rod is an electrical conductor; the others are insulators.

*May 7, 2014*

**Physics**

C=q/Δφ q=C Δφ

*May 7, 2014*

**engineering**

In the question I have some strenths and w/c ratios of some specimens and it is asking me about the range,molds?Also,How many specimens should be taken for each batch of concrete? This is a question before we learn it,so really have some understanding problems.

*May 4, 2014*

**engineering**

Hello guys.I got a homework and seem like I am stocked. a)What type of experiments should be done to find the relationship between the strength of concrete and water/cement ratio. b)what will be the range of the water/cement ratio? It would be great if you help.Thank you!

*May 4, 2014*

**Math**

To Damon: thank you so much for your help :))))))

*April 29, 2014*

**Math**

To Steve: I just copy that from my child's textbook as it is. Thank you for your great advice, I'll forward it to his math teacher.

*April 29, 2014*

**Math**

Hector has $450 and saves 20 per week. Tim has $1200and spends $30 per week.write a system equation for this situation

*April 29, 2014*

**Physics 194**

d•sinφ=kλ, tanφ=x/L. => d•x/L=kλ λ₁=dx₁/Lk λ₂=dx₂/Lk λ₁/λ₂=dx₁Lk/dx₂Lk= x₁/x₂ λ₂=λ₁x₂/x₁=630•0.21/0.26=508 nm

*April 25, 2014*

**Physics**

bsinφ=k λ sinφ=kλ/b, a) sinφ=1•630•10⁻⁹/0.020•10⁻³=0.0315 φ=1.8° b) sinφ=1•630•10⁻⁹/0.20•10⁻³=0.0035 φ=0.18° c) sinφ=1•630•10⁻⁹...

*April 25, 2014*

**physics**

a=ω²R, F(fr)=μN=μmg, ma =F(fr) => mω²R₁= μmg m(2ω)²R₂=μmg ω²R₁=4ω²R₂ R₂=R₁/4

*April 24, 2014*

**physics**

Imagine that F₂ is along the x-axis, F is along y-axis, and F₁ is directed to the “north-west”. The angle between F and F₁ is α. sin α = F₂/ F₁=1/2 α=30° Thus, the angle between F₁ and F₂ is 90°+30°...

*April 19, 2014*

**Physics**

W=mg

*April 18, 2014*

**physics**

1/λ₁ =Z²R[(1/n²) – (1/m²)] =2²•1.1•10⁷[(1/1²) –(1/3²)] λ₁=2.56•10⁻⁸ m 1/λ₂ =Z²R[(1/n²) – (1/m²)] =2²•1.1•10⁷[(1/2²) –(1/...

*April 17, 2014*

**physics**

E=5eV=8•10⁻¹⁹ J λ=h/p = h/sqrt(2mE) = =6.63•10⁻³⁴/sqrt(2•9.1•10⁻³¹•8•10⁻¹⁹)=5.5•10⁻¹⁰ m

*April 17, 2014*

**physics**

S=Energy per unit time/Area = Nhf/A= =4Nhc/πD²λ= =4•1.42•10¹⁸•6.63•10⁻³⁴•3•10⁸/π•(1.82•10⁻³)²•524•10⁻⁹= =2.07•10⁵ W/m² Electric ...

*April 17, 2014*

**physics**

(a) 1/do+1/di =1/F 1/di=1/F-1/do=1/48.5•10⁻³- 1/3.85•10⁸. di≃48.5•10⁻³m x/di=D/do x=D•di/do =3.48•10⁶•48.5•10⁻³/3.85•10⁸.= =4.38•10⁻⁴ m (b) 1/do₁+1/di₁...

*April 17, 2014*

**physics**

tan(α/2) =x/L => x=L tan(α/2) Coordinate of the second dark fringe is x=(2k+1)Lλ/d L tan(α/2)= (2k+1)Lλ/d d/λ =(2k+1)/tan(α/2)= (2•2+1)/tan3.6°=79.5

*April 17, 2014*

**Physics**

(i) h=gt²/2 t=sqrt(2h/g)=sqrt(2•10000/9.8)=45.2 s. (ii) v=800000/3600 = 222.2 m/s s=vt =222.2•45.2 =10044 m (iii) x=0 (since the horizontal speed of the cargo is constant)

*April 14, 2014*

**Physics**

The speed of sound at 20°C v=343 m/s s=vt=343•3=1029 m

*April 14, 2014*

**Physics**

If the detector (radar)is at rest and the source (moving car that reflects the sound)) is moving away from the detector, the observed frequency f is less than the actual frequency f₀. The speed of sound v =343 m/s f=f₀v/(v+V) V=v(f₀-f)/f =343•(1.5-1.4)&#...

*April 14, 2014*