# q

Most popular questions and responses by q
1. ## Physics

A refrigerator has a coefficient of performance of 4.0. When removing 2.4x10^4 J from inside the refrigerator, how much energy is sent into the environment?

A rectangular piece of paper with perimeter 100 cm is to be rolled to form a cylindrical tube. Find the dimensions of the paper that will produce a tube with maximum volume. I have made it up to getting an equation for V(w).

For an outdoor concert, a ticket price of \$30 typically attracts 5000 people. For each \$1 increase in the ticket price, 100 fewer people will attend. The revenue, R, is the product of the number of people attending and the price per ticket. a) Let x

4. ## Calculus

There are 50 apple trees in an orchard, and each tree produces an average of 200 apples each year. For each additional tree planted within the orchard, the average number of apples produced drops by 5. What is the optimal number of trees to plant in the

5. ## English.

Please check my answers? Letter of Recommendation Mary O'Dell PLTW Program Willow High School 1400 Old Tamah Road Irmo, SC 29067 April 11, 2007 Subject: Letter of Recommendation for Mr. Chris Moses To Whom It May Concern: Chris studied under my supervision

6. ## physics

In attempting to jump up a waterfall, a salmon leaves the water 2.0 m from the base of the waterfall. With what minimum speed must it leave the water in order just to make it up a waterfall 1.6 m high?

7. ## AP Chemistry

The Ksp of Ni(CN)2 is 3.0 × 10−23. What is the molar solubility of Ni(CN)2 in a 0.065 M KCN solution? Answer in units of mol/L. I found that the normal molar solubility is 1.957x10^-8, but I don't know how the KCN solution affects it. Sig figs aren't

8. ## Math

water flows over a dam at a rate of 500 gallons per minute write a function rule relating the amount of water a that flow over the dam to the number of minutes m that have passed what are the initial value and rate of change

9. ## chemistry

How would you do this question: A student dissolved 5.0 g of vitamin C in 250 mL of water. The molar mass of ascorbic acid is 176 g/mol, and its Ka is 8.0 × 10−5. Calculate the pH of the solution. Note: Abbreviate the formula of ascorbic acid to HAsc.

10. ## Math 3rd

Tim tracked the change in outside temperature one afternoon. He recorded a temp of 85.4 f at noon. The Temperature then rose 3.85 f over the next 4 hours. At 5:00 Tim recorded the temperature of 89.25 f how did the temperature change betwn 4:00pm and

11. ## MATH157

SUPPOSE YOU BUY 1 TICKET FOR \$1 OUT OF A LOTTERY OF 3000 TICKETS. IF THE PRIZE FOR THE ONE WINNING TICKET IS TO BE \$500, WHAT ARE YOUR EXPECTED WINNINGS?

12. ## math

simplify (8*10^7)(7*10^4) i think it's 5.6*10^10 simplify (3*10^6)(8*10^-4) i think it's 2.4*10^3 Astronomers measure large distances in light-years. One light-year 5.88*10^12 mi Star is 9.8*10^1 light years from Earth in scientific notation how many miles

13. ## science

Egg-laying land animals have evolved to produce eggs with tough shells to ensure that A .external fertilization can take place. B.the egg and sperm can fuse C.parental care is unnecessary*** D. the developing embryo does no dry out

14. ## chemistry

i need help solving this Benzoic acid is a weak, monoprotic acid (Ka = 6.3 × 10−5). Calculate the pH and the percent dissociation of each of the following solutions of benzoic acid. Then use Le Châtelier’s principle to explain the trend in percent

15. ## AP Chemistry

Calculate ΔHrxn for the following reaction: C(s)+H2O(g)→CO(g)+H2(g) Use the following reactions and given ΔH values: C(s)+O2(g)→CO2(g), ΔH= -393.5 kJ 2CO(g)+O2(g)→2CO2(g), ΔH= -566.0 kJ 2H2(g)+O2(g)→2H2O(g), ΔH= -483.6 kJ

16. ## Physic

A space station that does not rotate cannot simulate gravity for its occupants. A)True B)False From within a rotating reference frame, the centrifugal force simulates gravity. A)True B)False On a rotating station, a person at the center of the station, in

17. ## chemistry

Determine the number of representative particles in each of the following and identify the representative particle. a. 13.0 mol Ag b. 23.7 mol H20 c. 0.178 mol NaCl

18. ## chemistry

how many grams of CaCl2 would be dissolved in 1.9 liters of a 0.2 molarity solution of CaCl2?

19. ## algebra

If Jenny's car uses less gas per mile driven than Sandra's truck, how does the graph representing the rate of change of Sandra's truck compare to the graph representing the rate of change of Jenny's car?

20. ## chemistry

Determine the number of moles of sulfate ions present in 1.20 mol iron(III) sulfate (Fe2(SO4)3).

21. ## life science

Explanation of why the process of mitosis and meiosis are both important to a living organism. When would an organism need to undergo the process of mitosis? When would an organism need to undergo the process of meiosis? What would happen if meiosis did

22. ## Chemistry

Consider this equilibrium N2(g) + H2(g) NH3(g) +94 kJ The equilibrium law exoression for the balanced chemical equationwould be A. [N2][H2]/[NH3] B. [NH3]/[H2][N2] C. [NH3]2/[H2][N2] D. [NH3]2/[H2]3[N2] E. 2[NH3]2/3[H2]3[N2]

23. ## chemistry

Calculate the amount of heat absorbed when 58 g of steam at 117◦C are completely converted to ice at −32.5◦C. Specific Heat: H2O(s) = 2.09 J/g◦C H2O(l) = 4.18 J/g◦C H2O(g) = 2.03 J/g◦C Heat of Fusion = 334 J/g Heat of Vaporization = 2260 J/g

24. ## Calculus

Find a positive number such that the sum of the square of the number and its reciprocal is a minimum.

25. ## Calculus

Evaluate the surface integral. the double integral of (x^2 + y^2 + z^2)dS over Region S. S is the part of the cylinder that lies between the planes z = 0 and z = 5, together with its top and bottom disks Can anyone help?

26. ## english

What is the author referring to in this reading passage? Thus early had that one guest,--the only guest who is certain, at one time or another, to find his way into every human dwelling, --thus early had _______ stepped across the threshold of the House of

27. ## chemistry

A jogger runs at an average speed of 5.9 mi/h. If she starts a run at 11:15 am, what time is it after she covers 4.75 x 104ft?

28. ## Calculus

Linda has \$9000 to invest. She invested x dollars in an account that earned 3% simple interest and the remainder of the money in an account that earned 2.6% simple interest. In one year, both accounts together earned \$250 interest. How much was invested in

29. ## chemistry

A sample of silver chromate (Ag2CrO4) has a mass of 29.0 g. (a) How many Ag+ ions are present? (b)What is the mass in grams of one formula unit of silver chromate? (c) How many CrO42- ions are present?

30. ## physics

A 47.0 g golf ball is driven from the tee with an initial speed of 54.0 m/s and rises to a height of 23.2 m. (a) Neglect air resistance and determine the kinetic energy of the ball at its highest point. What is its speed when it is 9.0 m below its highest

31. ## help with solving

x^2+(x-2)^2 = (2x-6)^2 solve for x. thanks so much. Please keep in mind that tutors here won't simply do your work for you. I'm sure you'll get a better response if you show your work as far as you can get, so tutors will know where you get stuck. =) it

32. ## math

a football player attempts a field goal from a distance of 52 yards. The ball reaches a maxium height of 9 yrds and lands 8 yards behind the uprights. If the uprights are 3 yards high. algebraically determine if the field goal was successful

33. ## Physics

A refrigerator does 18kJ of work while moving 115 kJ of thermal enegy from inside the refrigerator. What is its coefficient of performance?

34. ## Science

I need to know how to compare mouthwash and toothpaste...what to compare?.. compare bacteria samples in salaiva.

35. ## PHYS

You throw a bowling ball o the empire state building(381m high) 10m/s down- ward. How long does it take to get to the bottom?

36. ## engineering mechanics

A person A is trying to keep his balance while on a sled B that is sliding down an icy incline. Let mA = 78kg and mB = 25 kg be the masses of A and B, respectively. In addition, let the static and kinetic friction coefficients between A and B be μs = 0.4

37. ## maths

if 3x + 8 =20 - 3x, what is x

38. ## geometry

if 3x + 8 =20 - 3x, what is x

39. ## math

5x-3y=11 4x-7y=18

40. ## algebra

i need help finding the base. this is the equation i got after work it out halfway. 42/h+h+sqroot(42/h)^2+h^2=20 ft how can i find B & H. How should i go about. Thanks. Isnt the sqrt of (42/h)^2 just 42/h ? Then, multipy both sides of the equation by h,

41. ## algebra

solve for x (24+2x)(10+2x) - 240 = 152 First multiply. 24(10) = ___ 2x (2x) = ____ Now subtract 240. Can you finish the problem from here? dont i need to put this in equatic equation to solve for x. cause i need to find the width of a small rectangle

42. ## Algebra

110 student went to the lake for a boat ride. there were 8 both (each would safely hold the same number of student), and all but 14 students could go for a ride. those remaining 14 students had to wait until first students finished their ride before they

43. ## Algebra II

From 1990-1994 the mail order sales of health products can be modeled by S= 10t^3+115t^2+25t+2505 where S is the sales (in millions) and t the number of years since 1990. In what year were about \$3885 million health products sold.

44. ## Math

2x√3x*2√x i was wondering how to simplify this

45. ## Complex Math

Compute all possible values of e^i

46. ## physical

David's clock ticks once for every two of Phil's clock ticks. How fast is Phil moving by David?

47. ## physical

Franky claims he has a mass of 65kg. He is sitting on a spherical bouy that oats just barely submerged under water. When he gets o it rises halfway out of the water. What must the radius R in centimeters of the sphere be for him to be telling the truth?

48. ## Quick Math Question

How do I add time? If a person worked 4 1/2 hours on Monday, 4 1/2 hours on Tuesday and 2 hours on Wednesday, does that add up to 12 hours? If not, how much more time would the person need to work the next day to equal 12 hours?

49. ## american government

What is the difference between civil liberties and natural rights?

50. ## Math

2x(√3x^2)*2√x how would you simplify this?

51. ## multivariable calculus

Studying for a test, and saw this: Find the center of mass of the hemisphere x^2 + y^2 + z^2 = a^2; z>=0 if it has constant density. Any ideas?

52. ## Math

For a class C corporation in Louisiana, the amount of state income tax S is deductible on the federal return and the amount of federal income tax F is deductible on the state return. With \$200,000 taxable income and a 30% federal tax rate, the federal tax

53. ## Chemistry

which of the following statement are true for all electric cells? I. electrons flow from the anode to the cathode II. reduction occurs at the anode III. oxidation occurs at the cathode IV. oxidation occurs at the anode V. reduction occurs at the cathode A.

54. ## accounting

Derm Travel Agency accepted a four-month, 9% interest rate, 52.000 note from one otits customers on May 1, 2008. The entire balance is payable at the notes maturity. Prepare the May 31 adjusting journal entry related to this note. Do I debit cash and

55. ## Chemistry

why different detergents have different price?on what physical properties are their qualities based?

56. ## math

The sales representative informs you that there are two floor plans available, and that there are a total of 56 houses available. Use x to represent floor plan #1 and y to represent floor plan #2. Write an equation that illustrates the situation. The sales

57. ## Life Science

How did Mendel’s approach to answering scientific questions differ from that of his contemporaries? Thank you for using the Jiskha Homework Help Forum. You might want to see the answer just posted for Diana.

58. ## Life science

are humans subject to the same pressure of natural selction as other organism Humans show signs of natural selection occuring, according to these studies. http://www.news.cornell.edu/stories/Oct05/Bustamante.kr.html (Broken Link Removed)

1. ## calculus

posted on January 30, 2019
2. ## Social Studies

14. A "(in the former Soviet Union) the policy or practice of more **open** consultative government and wider dissemination of information, initiated by leader Mikhail Gorbachev from 1985." 15. B "(in the former Soviet Union) the policy or practice of

posted on January 24, 2019
3. ## Edtech

q

posted on December 13, 2018
4. ## Science

-)_(- is correct tysm

posted on October 23, 2018
5. ## Astronomy

Wrong

posted on September 27, 2018
6. ## Science

Bruh is correct! Thanks!! Answers: 1. A 2. D 3. B 4. B 5. A

posted on September 26, 2018
7. ## Social Studies

posted on September 21, 2018

oof

posted on September 18, 2018
9. ## Math

150

posted on February 28, 2018
10. ## statistics

3799

posted on February 22, 2018
11. ## Chemistry

The phase fraction is calculated using the 'Lever Rule'. I can't figure out how to do it, but it involves using this formula- X = (c-b)/(a-b) Where a, b, and c are distances between x-coordinates at various phase boundaries. But the phase diagram in this

posted on December 3, 2017
12. ## Chemistry

Ghh

posted on December 1, 2017
13. ## MATH HELP

no its wrong

posted on September 11, 2017
14. ## chemistry

q

posted on March 23, 2017
15. ## Chemistry

posted on March 21, 2017
16. ## SCGC

!@#\$%^&

posted on January 23, 2017

Aboringjob

posted on December 6, 2016
18. ## Improving writing assignment

I have noticed that in the last three months, the performance and qualities of work has been compact due to workloads unbalanced, since Jessica Hilo our executive manager has been on medical leave for last four months. Her responsibilities have been shared

posted on June 3, 2016
19. ## math

123145

posted on December 7, 2015
20. ## social studies

what colonies French find as a result of the northwest passage way.

posted on November 17, 2015
21. ## Soc Stud

so its c

posted on October 21, 2015
22. ## Maths Probability

Anyone got right answer for c = ?

posted on May 25, 2015
23. ## Probability

Is that the right answer for c?

posted on May 25, 2015
24. ## probability

Let N be the numbers of passengers that show up. So p=0.9 and E[N]=0.9n and σ=(n*0.1*0.9)^1/2=0.3*n^1/2. Using Moivre-Laplace we have P(N≥300.5)≈0.01 Next you should use CLT, solving quadratic equation and find value of n

posted on April 29, 2015
25. ## Probability

Jacob, can you explain how did you get these answers? I want understand this problem

posted on April 15, 2015
26. ## English.

Thanks?

posted on March 12, 2015
27. ## AP Chemistry

I got it! The initial concentration of CN- would be 0.065 M rather than 0 M.

posted on January 20, 2015
28. ## AP Chemistry

The Ksp of Ni(CN)2 is 3.0 × 10−23. What is the molar solubility of Ni(CN)2 in a 0.065 M KCN solution? Answer in units of mol/L. I found that the normal molar solubility is 1.957x10^-8, but I don't know how the KCN solution affects it. Sig figs aren't

posted on January 20, 2015
29. ## physics

shut up

posted on December 8, 2014
30. ## PHYSICS

a

posted on November 5, 2014

thx!

posted on March 25, 2014
32. ## math

You receive an invoice for \$565.00 with terms 3/10, net 30. If you pay it immediately, how much will you pay?

posted on November 20, 2013
33. ## chemistry

Answer is 1480g Do the math. Someone already gave the formula. The cm cancels out after multiplying. Note: you have to cube the 5.5cm

posted on September 1, 2013
34. ## math

What?

posted on May 9, 2013
35. ## Quick Math Question

okay thx

posted on March 28, 2013
36. ## Auditing

qtfq

posted on April 4, 2012
37. ## social studies

Without our two great political parties cutting across economic and geographic interests, democracy as we know it could never have been made to function." The author of this statement probably meant to suggest that

posted on June 13, 2011
38. ## spelling

well what is it? i don't get it :'(

posted on May 5, 2011
39. ## Math

a.Set table as x,chair as y 90x+40y

posted on March 20, 2011
40. ## chinese

tian cai

posted on March 20, 2011
41. ## math

6 minutes

posted on March 7, 2011