# Posts by Verónica

Total # Posts: 411

**Physics **

A plutonium- 239 nucleus initially at rest undergoes alpha decay to produce a uranium-235 nucleus. The uranium-235 nucleus has a mass of 3.90 x 10^-25 kg and moves away with a speed of 2.62 x 10^5 m/s. Determine the minimum wage electric potential difference that is required ...

**chemistry**

If 25 g of NH4Cl is dissolved at 80C, how many additional grams would be needed to make the solution saturated?

**Maths**

156÷60=2.6

**Math**

A dictionary costs $24. The total cost of the dictionary and 4 identical diaries is the same as 7 diaries. How much does 1 diary cost?

**Algebra **

X is a number.It is divided by 3,and 5 is subtracted from the result.The new result is then multiplied by 7.If the final answer is 28,what number is X?

**Math**

Alicia, Bill, and Ross are in Group A. David, Maddie, and Shelby are in Group B.The students are going to have their pictures taken. They will stand in 2 rows by group, and group members cannot be separated. If 2 girls or 2 boys cannot be standing next to each other, how many ...

**Math**

Becky has $60 and Nina has $120. How much money must Becky give to Nina so that the amount of money Nina has is 5 times what becky has?

**Math**

Natalie had some marbles. She gave 1/3 of them to her brother,who kept 12 marbles for himself and gave the rest to 5 friends.If each friend received 7 marbles, how many marbles did Natalie have at firts?

**Math**

A toy maker packed 29 boxes with 9 tops each and had 3 top left. How many more boxes of tops would he have if he had packed 3 tops into esch box instead?

**Math**

Holly left her apartment and walked up 3 floors to return a book to Kayla. She then went down 4 floors to Paige's place to get the class noted from her. Finally?Holly walked up 2 floors to look for Jenna, who was not home. If Jenna lives on tje eighth floor, which floor ...

**Math**

carmela cut a cake into 12 equal-sized pieces. She ate 2/12 of the cake and her brother ate 3/12 of the cake.What fraction of the cake

**Algebra**

A rhombus ABCD has opposite vertices at A(-3,2) and C(9,-2). Find the equations of its diagonals. One of the other vertices is B(4,3). Find the fourth vertex D Equation of AC Equation of BD Coordinates of D

**Algebra PLEASE HELP ME**

oh, okay. thank you very much for your help

**Algebra PLEASE HELP ME**

Why is the base BC is 13, its because x2-x1? and why is 12 in A?

**Algebra PLEASE HELP ME**

find the equation of the straight line through A(3,20) which is perpendicular to the line passing through the points B(-2,8) and C(11,8). Hence, find the area of the triangle ABC, giving your answer in the simplest possible form.

**Math**

A teacher tallies up the grades on a math test in a class of 34 students, the results are A1, B11, C16, D3, F1. What is the empirical probability of a student getting a C? Express as a fraction.

**Finance**

I'm struggling with being able to solve this question: A company wants to raise money in the capital markets. The firm intends to sell $18 million of common stock; the expected return is 15%. In addition, the company plans to issue $5 million of debt, the cost of this debt...

**Chemistry**

Boron is one of the exceptions, correct? It has 6 valence electrons.

**Chemistry**

Which of the following compounds has an atom with an unfilled valence shell of electrons? A) H3O+ B) BF3 C) CH3OH D) NaI

**Physics**

A 70kg wannabe stuntman at the edge of a roof top jumps vertical up with a speed of 4m/s and falls on a trampoline 2meters below where he started. If the trampoline acts like a Hooke's spring and does a maximum extension of 0.284m going down towards ground, what is the ...

**Physics**

A 70kg wannabe stuntman at the edge of a roof top jumps vertical up with a speed of 4m/s and falls on a trampoline 2meters below where he started. If the trampoline acts like a Hooke's spring and does a maximum extension of 0.284m going down towards ground, what is the ...

**Chemistry**

When a 0.326 g sample of FeCl2·xH2O is heated to remove all water, a mass of 0.254 g remains. Determine the value of x.

**precal**

The product of two numbers is 48 and the sum of their reciprocal a is 1/3. Determine the value of the two numbers.

**Finance**

Following are selected financial data in thousands of dollars for the Hunter Corporation. 2012 2011 Current assets $ 500 $400 Fixed assets, net 700 600 Total assets 1,200 1,000 Current liabilities 300 200 Long-term debt 200 200 Common equity 700 600 Total liabilities and ...

**Physics**

An air plane has a mass of (1.7x10 to power 6) kg, and the air flow past the lower surface of the wings at 95m/s. If the both wings have a surface area of 1200cubic metre, how fast must the air flow over the upper surface of the wings if the plane is to stay in the air?

**Physics**

During each heart beat, approximately 70cubic cm of blood is from the heart at an average pressure of 105mmHg. Calculate the power output of the heart, in watts, assuming 70 beats per minute.

**Physics**

Is the tension on a rope zero just before a person releases it after swinging from one side of a river to the other?

**Physics**

A 56kg student runs at 5m/s, grabs a hanging rope, swings out over a lake. He releases the rope when his velocity is zero. The angl when he releases the rope is 29.25degrees. What is the tension in the rope just before he releases it? What is the maximum tension in the rope?

**Physics**

A 56kg student runs at 5m/s, grabs a hanging rope and swings out over a lake. He releases the rope when his velocity is zero. The length of the rope is 10m, what is the angle when he releases the rope? (The person swings from the centre to the right).

**maths,science,geography and life science**

What is restorative justice intention in process of human rights?

**trig, precalc, math, algebra, trigonometry**

Rewrite: tan(cos^−1 (v)) as an algebraic expression in v. Please help me understand.

**math**

How is solving -4x=-4.8 different from solving -1/4x = -4.8? How are the solutions related?

**math**

2779?

**math**

Find the 5,550th term in the sequence 4 1/2, 5, 5 1/2, 6, 6 1/2

**Chemistry**

How many grams of potassium nitrate, KNO3 are required to make 250 mL solution with a molarity of 0.40 M?

**Triginometry**

a yardstick, held vertically on a level surface, cast a shadow 1 foot 5 inch long. Find the tangent of the angles that the rays of the sun make with the horizontal.

**Math**

The area of a rectangle is 247 cm^2. The width and length are both whole numbers greater than 1. What are the dimensions of the rectangle?

**Math**

I didn't see it sorry.

**Algebra 2**

Donald's Jaguar loses value at 8% per year for the first nine years when should he sell it if he wants to receive 62% of what he paid for it?

**Algebra**

how do you calculate probabily or this problem. A bag has 8 red, 6blue, 2 yellow and 7 green marbles. What is the probability of selecting a red, not replacing it and selecting a green? 6/21 * 7/21 =42/21

**health**

What is a way to boost your self-esteem? A.) Worry about other's opinions. B.) Exhibit risky behaviors. C.) Maintain a negative attitude. D.) Form close relationships. I think the answer is D, but I don't want to get it wrong.. Help?

**science**

A box weighing 180 newtons is hanging by rope as shown in the figure. Find the tension T¿.

**math**

John is doubling a cake recipe. The recipe calls for 1/4 cup of butter. How much butter should John use?

**Math**

1. C 18 2. C -1 3. B -15 4. C 4 5. A 12 6. A 19 7. C -16 8. B 12

**Math**

#8 is b l + (-3)=9 so under -3 put positive 3 and under the 9 put positive 3. The -3 and positive 3 cancel out add 9 +3 = 12

**math**

In a science experiment, the temperature of a glass of water rose 18.24 degrees after six hours. If the temperature rose the same number of degrees per hour, then how many degrees did the water increase per hour?

**calculus**

radioactive Carbon 14 in a dead organism decays according to the equation A=A e^.000124t where t is in years and A0 is the amount at t=0. Estimate the age of a skull uncovered in an archeological site if 10% of the original Carbon 14 is still present.

**science**

calculate the net force on an object that has a mass of 12kg and acceleration of 4m/sec

**higher school**

determine the fishers' ideal price index formular from both the laspeyre and paasche price indices formular

**Statistics**

With a known population mean of 100, and a known standard of error of the mean of 7.5, what is the probability of selecting at random a sample whose mean is equal to 110 or greater?

**Algebra**

I am so very confused :(

**Algebra**

I need some help with this question I really don't understand it and some help going through this problem would be really appreciated :) Use the fact that a/b/c/d=a/b / c/d to simplify each rational expression. State any restrictions on the variables. x^2-1/x^2-9 / x^2+3x-...

**6TH GRADE MATH**

N<7 is the correct answer

**Chemistry**

How would I do it DrBob222 . I keep getting the wrong answer.I also don't even know what you notations mean

**Math**

Explain how to solve the following system of equations. What is the solution to the system? 2x+2y+z=-5 3x+4y+2z=0 x+3y+2z=1

**Math**

Would the answer be c?

**Math**

Every year in Delaware there is a contest where people create cannons and catapults designed to launch pumpkins as far in the air as possible. the equation y=15+110x-16x^2 can be used to represent the height, y, of a launched pumpkin, where x is the time in seconds that the ...

**math**

At a given time, Saturn was 9.1 x 10 to the 8th miles from the sun and the earth was 9.3 x 10 to the 7th miles from the sun. by what distance is one planet closer to the sun than the other planets?

**PHYSICS**

A uniform plank with mass 20kg and length 12m extends 2m over the edge of a building. A 40kg crate is slid out on the plank. how far can the crate be pushed without toppling the plank? A. 0.5m B. 1m C. 1.25m D. 1.5m E. 2m

**Physics**

A 3kg mass is sliding across a horizontal surface at a constant speed while being pulled by rope with tension 20N held at a 53 degree angle above the horizontal. The force of friction is most nearly A. 30N B. 12N C. 16N D. 20N E. 1N

**Struggling in Writing**

Thank you for your optimism! After reading your posts, I felt more encouraged and more motivated to try my best. Have a wonderful day! :) Writing well will be my goal!

**Struggling in Writing**

Should I be ashamed for being a poor writer and reader,since I am in 12 th grade this year? Today,in writing class I struggled.. I could not identify the thesis of an article nor could I spot counterclaim that the author makes. I think I have dyslexia because I have a hard ...

**8th grade English/Language Arts**

Thank you Ms.Sue. You are very great with this homework helping are you the coordinator

**8th grade English/Language Arts**

Okay, please help me with the rest

**8th grade English/Language Arts**

1.)Why does the author of “Always to Remember” discuss Maya Ying Lin’s background? a.)to show that she experienced hardships b.)to appeal to Chinese-American readers c.)to show its influence on her design d.)to show her disinterest in architecture 2.) Which of ...

**8th grade; English**

Can someone post the answers I am tutoring my brother with english and i need some work problem i think this is a good work examples.. answer asap

**statisitcs**

The combined math and verbal scores for students taking a national standardized examination for college admission is normally distributed with a mean of 560 and a standard deviation of 180. If a college requires a student to be in the top 40 % of students taking this test, ...

**Science**

They were wrong because it said that in my book but thank you so much

**Science**

May you please tell me if these are true or false, if they are false then can I have the true statement, thank you In the water cycle, water returns to Earth as (condensation) usually in the form of rain or snow During dry weather, the water level in a small pond drops because...

**math**

I thought that you had to cross off the two zero's from each side.That is what my teacher has told me.

**math**

Yes it could be simplified to 5/9.

**MATH**

A HUMMINGBIRD BEATS IT WINGS 53X SEC HOW MANY TIMES DOES THE HUMMINGBIRD BEATS IN 5 SEC

**Science**

Why are aboriginal clan systems considered human social systems?

**English**

Start with your interests like. Fore say you like the arts. Explain how you feel about it. The begging should always be different that the others. Something unique about yourself. Of course you can also start saying what is you name. Bot it's your call

**AP Physics**

Two locomotives approach each other on parallel tracks. Each has a speed of v = 85 km/h with respect to the ground. If they are initially d = 7.0 km apart, how long will it be before they reach each other?

**AP Physics**

A car traveling 92 km/h is 130 m behind a truck traveling 75 km/h. How long will it take the car to reach the truck?

**health**

what is the answer?

**Pre Cal**

Two forces with magnitudes of 100 and 50 pounds act on an object at angles of 50° and 160° respectively. Find the direction and magnitude of the resultant force. Round to two decimal places in all intermediate steps and in your final answer.

**chemistry**

When 3.00 moles of sodium are reacted with large amounts of chlorine gas 145.8 g of sodium chloride are produced determine percentage yield

**Finacial Accounting.**

I am really struggling with this question and my accounting book is no help at all. A company has $4500 in net sales, $3200 in gross profit, $1300 in ending inventory, and $1800 in beginning inventory. What is the cost of goods sold? Im not looking for the answer, just a ...

**Chemistry**

A solution buffered at a pH of 5.00 is needed in an experiment. Can we use acetic acid and sodium acetate to make it? If so, how many moles of NaC2H3O2 must be added to a 1.0L of a solution that contains 1.0 mol HC2H3O2 to prepare the buffer. The Ka of acetic acid is 1.8x10^-5...

**Chemistry**

Determine the concentration of CO32- ions in a 0.18 M H2CO3 solution. Carbonic acid is a diprotic acid whose Ka1 = 4.3 × 10-7 and Ka2 = 5.6 × 10-11.

**Chemisty**

A 0.411 g sample of powdered copper mixed with an inert, soluble additive was fully consumed by 23.4mL of 0.602M nitric acid, producing copper (II) nitrate, water, and nitric oxide. What is the percent copper by mass in the sample? 3Cu + 8HNO3 = 3Cu(NO3)2 +2NO =4H2O

**Chemistry**

what is the pH solution in which 15 mL of 0.10 M NaOH has been added to 25 mL of 0.10 M HCl

**Chemistry**

the answer is 0.75mol SO2 but I don't understand where to even begin

**Chemistry**

Consider the following equilibrium. 2 SO2 (g) + O2 (g) 2 SO3 (g) The equilibrium cannot be established when __________ is/are placed in a 1.0-L container.

**Chemistry**

what volume (mL) of 0.0962M NaOH is required to neutralize 10.0mL of 0.128M H2SO4? I got 26.6mL

**algebra**

4x^3-6.68E-7x^2+1.67E-8x-1.04E-10 = 0

**Math**

4x^3-6.68E-7x^2+1.67E-8x-1.04E-10 = 0

**Chemistry**

I posted this last night, A 0.500L vessel initially contains 0.0125 mol of H2S2 . Find the equilibrium concentrations of H2 and S2. Kc = 1.67 x 10^-7 2 H2S <--> 2 H2 + S2 I have come up with this equation so far, but I am lost now because I don’t even know if this ...

**Chemistry**

How many grams of pure H2SO4 can be obtained from 250 grams of iron ore if the ore is 82% FeS2? The reactions involved are given below: 4FeS2 + 11 O2 --> 2 Fe2O3 + 8 SO2 (95% efficient) 2SO2 + O2 --> 2SO3 (90% efficient) SO3 + H2O --> H2SO4 (90% efficient)

**Chemistry**

I got this equation but now I am lost 1.67x10^-7 = ((4x^2)(x)) / (0.000625-4x^2)

**Chemistry**

A 0.500L vessel initially contains 0.0125 mol of H2S2 . Find the equilibrium concentrations of H2 and S2. Kc = 1.67 x 10^-7 2 H2S <--> 2 H2 + S2

**Chemistry**

I posted this question before and the answer is suppose to be 6.8 L but I keep getting 6.12 L dinitrogen pentoxide n2o5 decomposes by a first-order decomposition in chloroform solvent to yield NO2 and O2. The rate constant at 45°C is 6.2 x 10^-4 mins^-1. Calculate the ...

**Chemistry**

I keep getting 6.12 and the answer is suppose to be 6.8

**Chemistry**

dinitrogen pentoxide n2o5 decomposes by a first-order decomposition in chloroform solvent to yield NO2 and O2. The rate constant at 45°C is 6.2 x 10^-4 mins^-1. Calculate the volume of O2 obtained from the reaction of 1.00 mol N2O5 at 45°C and 770 mmHg after 20.0 hours...

**Chemistry**

Or this balanced equation actually N2O5 = 2 NO2 + 1/2 O2

**Chemistry**

dinitrogen pentoxide n2o5 decomposes by a first-order decomposition in chloroform solvent to yield NO2 and O2. The rate constant at 45°C is 6.2 x 10^-4 mins^-1. Calculate the volume of O2 obtained from the reaction of 1.00 mol N2O5 at 45°C and 770 mmHg after 20.0 hours...

**Chemistry**

Nevermind I got the answer myself!

**Chemistry**

The potassium salt of benzoic acid, potassium benzoate, KC7H5O2, can be made by the action of potassium permanganate on toluene, C7H8. C7H8 + 2 KMnO4 --> 2MnO2 + KOH + H2O If the yield of potassium benzoate cannot be realistically be expected to be more than 71%, what is ...