1. Physics

Hot air balloons float in the air because of the difference in density between cold and hot air. In this problem, you will estimate the minimum temperature the gas inside the balloon needs to be, for it to take off. To do this, use the following variables

2. stats

A company with a large fleet of cars hopes to keep gasoline costs down and sets a goal of attaining a fleet average of at least 26 miles per gallon. To see if the goal is being met they check the gasoline usage for 50 company trips chosen at random,

3. algebra 2

In the formula A(t) = A0ekt, A is the amount of radioactive material remaining from an initial amount A0 at a given time t, and k is a negative constant determined by the nature of the material. An artifact is discovered at a certain site. If it has 72% of

4. trig

An airplane has an airspeed of 450 km/hr bearing N45E. The wind velocity is 30 km/hr in the direction N30W. What is the ground speed and what is its direction?. I have gotten this far: A= 450cos(45), 450sin(45) = (318.20, 318.20) W= 30cos(120), 30sin(120)

the crucible is not fired, as the procedure suggests, but had retained some impurities from previous use(or it could be oily smudges from fingers). the mass of the "dirty" crucible is recorded. however the impurities are burned off in the experiment. how

6. chemistry

What is the percent yield for the reaction PCl3(g) + Cl2(g) --> PCl5(g) if 119.3 g of PCl5 are formed when 61.3 g of Cl2 react with excess PCl3? I don't understand how to set this up?

7. Chemistry

a sample of gas of unknown pressure occupies 0.766 L at the temperture of 298k the same sample of gas is than tested under known conditions and has the pressure of 32.6kPa and occupies 0.664 L at 303 k. What is the original pressure of gas

8. Physics

A string with a linear density of 0.035 kg/m and a mass of 0.014 kg is clamped at both ends. Under what tension in the string will it have a fundamental frequency of 100 Hz? The correct answer is 270N but I don't know how to get there. Here are some of the

9. Science

a sample of Ca3(PO4)2 contains 3.1g phosphorus then the weight of Ca in the sample is ?

10. Physics

During launches, rockets often discard unneeded parts. A certain rocket starts from rest on the launch pad and accelerates upward at a steady 3.50 m/s^2. When it is 255 m above the launch pad, it discards a used fuel canister by simply disconnecting it.

11. physics

Two charged dust particles exert a force of 5.3 x 10^-2 N on each other. What will be the force if they are moved so they are only one-ninth as far apart?

12. PHYSICS

A student is running at her top speed of 4.6 m/s to catch a bus, which is stopped at the bus stop. When the student is still a distance 38.9 m from the bus, it starts to pull away, moving with a constant acceleration of 0.177 m/s^2. A) For how much time

13. Math

If 3000 dollars is invested in a bank account at an interest rate of 6 per cent per year, find the amount in the bank after 12 years if interest is compounded annually Find the amount in the bank after 12 years if interest is compounded quaterly Find the

15. PHYSICS!!

A car's engine can accelerate a car from rest to 30 m/s in 6 s. if the car's mass is 1300 kg, what is the power of the engine? can someone give me the answer because i just want to verify it with my own? thank you!

You are in a meeting with an international executive at his office. A colleague comes in to talk to him during your appointment and he accepts two phone calls. This probably means that: a.)he thinks you are less important than the other callers. b.)he is

17. physics

two forces whose magnitude are in the ratio 3:5 give a resultant equal to 35 newton if the angle between them is 60 degrees find the magnitude if the resultant

18. physics

a body travels half of its total path in the last second of its free fall from rest.what is the duration of fall?

19. physics

A ray of light enters the top of a glass of water at an angle of 36 degrees with the vertical. What is the angle between the refracted ray and vertical? The answer is 26 degrees but I keep getting 22 degrees. I used snell's law: n1sinθ1=n2sinθ2 for n1 I

20. che

1.0M FeCl3(H2O)6 IN 2M HCl + 2.0M FeCl2(H2O)4 WHAT ARE THE MAIN CHEMICAL REACTION...

21. chemistry

calculate the molar mass of an unknown whose mass was 0.846 g, and occupied a volume of 354 cm3 at a pressure of 752 torr and a temperature of 100 degrees celcius. I came up with .0114 moles, I want to know if this is correct.

22. Math 116

1.Write an equation of the line containing the given points and parallel to the given line (3,8); x+5y=3 2. Write an equation of the line containing the given points and parallel to the given line (-3,6); 5x=9y+2 3. Write an equation of the line containing

23. chemistry

Doing review for an exam and I can't find how to do this problem in my notes. 2 SO2 + 2 Cl2 -----> 2 SOCl2 + O2 from a previous problem I solved: rate=k[SO2]^2[Cl2] k = 467.666666... or in sig. figs 467 Energy reaction: T= 25 C The activation energy (Ea)

24. algebra 2

Find the inverse of the function. f(x) = e^-x + 5 f(x) = 10^x + 2

25. Chemistry

Question: A sample of Freon-12 (CF2Cl2) occupies 2.261 x 101 L at 337 K and 2.917 x 102 kPa. Find its volume (in L) at standard temperature and pressure (STP). Equation: p1v1/t1=p2v2/t2 My Work: (2.917 x 102 kPa)(2.261x101 L)/337K = (101.3 kpa)( x )/273 k

26. chemistry

Why are standard solutions of reductants less often used for titrations than solutions of oxidants?

27. Math

Sam gets deposits a total of \$3500 every three months to the bank which earns a 6.5% p/a. After five years how much will he have in his account? Ren wants to buy a new car that costs \$26255, so, he would deposit money into his savings account with an

28. math

A pair of dice is rolled and the sum of the dice is found. What is the probability of rolling a 7?

29. trig

During a 12-hour period, the tides in one area of the Bay of Fundy cause the water level to rise to 6 m above average sea level and to fall 6 m below average sea level. The depth of the water at low tide is 2 m as measured against a pier. a.) Suppose the

30. Math 116

1.Write an equation of the line containing the given points and parallel to the given line (3,8); x+5y=3 2. Write an equation of the line containing the given points and parallel to the given line (-3,6); 5x=9y+2 3. Write an equation of the line containing

31. American Gov

The major function of Congress: A)is to check the president B)is to inform the people C)is to enact legislation D)is to check the Supreme Court Is C the correct answer?

32. Pre-Calculus

Given that SIN Theta = -1/sqrt(10) and theta is in quadrant 4, find sin2theta and cos2theta. I'm not sure how to properly square the -1/sqrt10 and keep an exact answer other than decimal. Otherwise, my final answer is 1.632455533

33. Science

How much heat is absorbed by a persons hand if 100 grams of steam at 100°C is first converted to liquid water at 100°C and then cooled to normal body temperature?

34. psychology

What is the proper in-text citation for this source that has this many authors. Is this correct= In-text(Papalia, Olds, Wendkos, Feldman, Duskin, 2008, p. 34) References: Papalia, D.E. Olds, Wendkoss S., Feldman, Duskin R. (2008) A Child's world: Infancy

35. chemistry

for the reaction to generate 2‐phosphoglycerate (2PG) from 3‐phosphoglycerate (3PG, ΔG = 0.83 kJ/mol; ΔGo’ = 4.4 kJ/mol. (R = 8.31 x 10‐3 kJ•K‐1•mol‐1) a)What is the ratio of 3PG:2PG in cells at 37C? I got 5.52 as answer for this part but

36. Chemistry

Which of the following solution has greater density? 1. 100ml of saturated aqueous solution of Lif. (Ksp(Lif)=1.84*10^-3). 2. 100ml of saturated aqueous solution of Hg2F2. (Ksp(Hg2F2)=3*10^-6). (We can assume that adding the dissolved doesn't change the

37. chemistry

In beta decay, why does the atomic number increase by 1?

38. physics

a stone is thrown vertically upward with an initial velocity u from the top of tower, reaches the ground with a velocity 3u. what is the height of tower?

39. algebra 2

Rewrite the expression as the sum and/or difference of logarithms, without using exponents. Simplify if possible. Log of 7(p to the 5th root q to the 9th root) / t²

40. comp100

You have been hired as a consultant by your neighbor to help her with her computer. You notice that she has a screen full of icons which appear to be Word documents, Excel Spreadsheets and other graphic files. How would you help her organize her data i.e.

41. chemistry

500ml of a 1M solution of NaCl contains how many (Na+) ions. Can you show me how to get it

42. Java Programming

Don't know how to start.. Can anyone help me? For this program you are to create a two class application - a driver and a principal class - that reads in text interactively from the keyboard, and then reports on two aspects of the entered text. First it

43. Chemistry

Question: What mass of water, in grams, would have to be decomposed to produce 17.6 L of molecular oxygen at STP? Work: n=PV/RT x=(1 atm)(17.6 L)/(0.0821)(273 k) x = 1.27348295454546 1.27348295454546 x 2 = 2.54696590909092 Grams= Moles x 18.0 Grams =

44. Chemistry

Since the oxidation number of Chromium is +3, and the oxidation number of Silicon is -4. Why is the chemical formula for Chromium III Silicide Cr3Si2? Can somebody please explain to me please???????THANKS A LOT!!!

45. Integration by parts

integrate (e^x-x)^2 dx

46. physics

a car accelerates from rest at a constant rate 'a' for some time. after which it decelerates at a constant rate'b' and comes to rest. if the total time elapsed is t second, evaluate 1) the maximum velocity reached and 2) the total distance travelled.

47. physics

a car accelerates from rest at a constant rate 'a' for some time. after which it decelerates at a constant rate'b' and comes to rest. if the total time elapsed is t second, evaluate 1) the maximum velocity reached and 2) the total distance travelled. the

48. english 101

Some would argue that women are better friends than men. Those people might mention things like women are mothers and my mom is my best friend. Although this is true one must remember that men have all the necessary components to be women. With that being

49. chemistry

the molarity of a solution containing 40 grams of NaOH in 100 ml of solution is

50. geometry

one interior angle of a pentagon has a measure of 120 degree. the other four interior angles are congruent to each other. What is the measure of one of the four congruent angles?

51. trig

Given that SIN Theta = -1/sqrt(10) and theta is in quadrant 4, find sin2theta and cos2theta. I'm not sure how to properly square the -1/sqrt10 and keep an exact answer other than decimal. Otherwise, my final answer is Sin2Theta = -.7255970691 and cos2theta

52. Chemistry

A solution contains 153g Na3PO4 and 415g H2O. What is the percentage concentration of Na3PO4 in this solution

53. chemistry

if a sample of alloy containing magnesium and metal that doesn't react wtih hydrochloric acid are reacted, how much heat would be evolved from a 5 gram sample that is 30% magnesium?

54. chemistery

For the reaction to generate 2‐phosphoglycerate (2PG) from 3‐phosphoglycerate (3PG, ΔG = 0.83 kJ/mol; ΔGo’ = 4.4 kJ/mol. (R = 8.31 x 10‐3 kJ•K‐1•mol‐1) a)What is the ratio of 3PG:2PG in cells at 37C? b)Considering your result, is the

55. american history

among instances of corparate malfeasance in the early twenty first century, the scandal was the most shocking and economically damaging for employees and shareholders.

56. Chemistry

What mass of water, in grams, would have to be decomposed to produce 13.3 L of molecular oxygen at STP? How do I go about doing this problem?

57. Chemistry

If 17.14 grams of nitric acid are reacted with a large amount of aluminum metal, what volume of of hydrogen gas would be produced at STP? What would be the balanced equation for this problem?

58. to kill a mockingbird

what is the moment where boo radley and miss maudie BRING at reaction from Scout?? i Don't get the questions !!do we have to explain the moment when scout reacts toward to Boo radley and miss maudie? can i answer it like this: the moment where Boo radley

59. Math

what does this derivative mean? (d/dx)(d/dt)(x^2t + t^2x - 2x^3)

60. MATH

ok so I'm learning to solve problems like cos(x)=2 and sin(x)=5 I've wrapped my head around the process required to do so and I must say my brain is like @_@ mosh right now. Whenever I ask this question I never get a direct answer. I understand it's

61. Math

Mr smith flight took off at Vancouver at local time 1335. The flight was bounded for Sydney via hongkong. After 16.5h flight, mr smith reached hongkong at 1505 local time on the same day. The plane took off again after 2h 20min. The plane landed in sydney

62. Grammar

I need to know how to in-text citations using websites, is there any one that could explain this to me in plain english? All the websites I have found have confused me even more. Thank you.

63. chemistry

Why do Alkali Metals & Alkaline Earth Metals have so much difference in their properties?

64. Physics

A person in a kayak starts paddling, and it accelerates from 0 to 0.498 m/s in a distance of 0.554m. If the combined mass of the person and the kayak is 62.6, what is the magnitude of the net force acting on the kayak?

65. psy 220

The text summarizes positive psychology as being aware that humans are both creatures and creators of their personal and social worlds. What does this statement mean to you? Do you agree that humans are creatures as well as creators of their personal and

66. Math: Parabola, Vertex

Find the vertex of the parabola associated with the quadratic function. f(x)= -1/7x^2 - 2/11x + 1/121 (h,k)= What is the vertex of this quadratic function?

67. American Gov

The highest priority for most members of congress: A)ensuring that the constitutional system of checks and balances works properly. B)supporting his or her party's legislative platform C)getting reelected D)gaining a reputation among other members of

68. English

My assignment calls for a review of a movie or television show that tells us about the society in which we live. It must address the big-picture issues, not just the quality of the work. Could you tell me what you think about what I have written? Any

69. Chemistry

Three acids,HCl, H2SO4 and H3PO4 are all 6M in concentration. what are their normalities

70. Math

You invest \$25 in an account earning 7.5% interest per year. After how many years is it worth \$42.50?

71. math

pls. explain why there is no real number è that satisfies ither sinè=2 or cos è=2.

72. statistic

Identify the level of measurement for the following? 1)What state/country were you born? 2)What is the temperature outside rigth now? 3)Rank all of the courses you are currently.The class you look most forward to taking will be rank one ,next two ,and so

73. critique my essay

Hybrid English course is good but it has also bad sides. If a student is looking for flexible time and busy of work hybrid class is your choice. I enjoyed this class and my writing has improved. I found out what are my bad habits in writing, and I also

74. Calc 3

intersect x^2+y^2=36-8x^2-8y^2

75. Math

(a) translate the argument into symbolic form and (b) determine if the argument is valid or invalid. You may compare the argument to a standard form or use a truth table. If Nicholas Thompson teaches this course, then I will get a passing grade. I did not

76. Math

Write each of the following in the indicated base. (a) 1021three to base ten. (b) 534 to base twelve (c) MCMLXII to base ten

77. Physics

The force of gravity on a 2.0 kg rock is twice as great as on a 1 kg rock. Why doesnt the heavier rock fall faster?

(2x-7))6x+9)

79. Chemistry

If 16.01 grams of sulfuric acid are reacted with a large amount of aluminum metal, what volume of hydrogen gas would be produced at STP? What is the balanced equation?

80. american history

when postwar expansion slowed in the 1950's an economic stimulus was provied by

81. lotto 5/90

The first 5 numbers at random in week 1 is 86-47-33-67-61 and last 5 numbers the same week 1 is 14-80-61-43-82 The first 5 numbers in week 2 73-55-18-2-26 The last 5 numbers the same week 2 64-29-83-86-11 The first 5 numbers in week 3 27-66-8-7-69 The last

82. child psychology

I need help with an example of cognitive perspective

83. chemistary

experment to determine the PH in different samples need in our daily life. CBSE 9 class its holiday homework plzz tel

84. CHEMISTRY

Analyze the properties of a sodium atom and a sodium ion. What are the differences in mass, stability, and reactivity that are caused due to the differences between the sodium atom and sodium ion?

85. english

This is the first paragraph of my essay, how does it look? Imagine being 6’3” in the eighth grade and everyone in the school making comments about your height. There are definitely advantages and disadvantages to being tall. My best friend’s mother

86. Chemistry

How can a mixture of ammonium chloride,KCl,lead(2)chloride could be separated in the laboratory

87. government

Campaign spending tends to be greatly more important: A)For republican candidates B)For democratic candidates C)For challengers and non-incumbents rather than incumbents. Is the answer C?

88. algebra 21

Solve the equation. If necessary, round to thousandths. 3^(2x + 1) = 27

89. physics

two velocities each 5 ms-1 are inclined to each other at 60 degrees find the resultant

90. concude refuting paragraph

i don't know what to do on this one. my teacher told that i need to get the readers attention again back to my thesis which is girls are better friends than men. here's the paragraph. However, some people think that men are better in handling friendships.

91. insurance

by signing an "assignment of benefits" statement , a patient is?

92. Chemistry

60 grams of NaOH, a solid, will dissolve in 40 grams of H2O.what is the solute and solvent for this solution

93. Chemistry

How many grams of NaCl are neeeded to make 100ml of a 2M solution of NaCl

94. American History

In Jefferson's view, George Washington's action in addressing the Whiskey Rebellion

95. The Age of Discovery To The American Experiment

The first stirrings of the first Great Awakening took place in

96. POLITITICAL SCIENCE

CAN YOU PLEASE SHOW ME AN EXAMPLE OF HOW TO WRITE AN ESSAY FROM A MOVIE USING A.P.A. FORMAT?

97. Chemistry

300 ml of a 0.5NKOH solution, how can it be neutralized

98. Social Studies

The Supreme Court usually only accepts a writ of certiorari when: A. they have a light case load and can take a few extra cases. B. there is a significant point of law to consider. C. two members of the Court feel it is important to hear a particular case.

99. Social Studies

Individual rights were included in the constitution because: A. Conflicts between individuals and the government remained unsolved. B. The people demanded a listing of rights C. The distinction between civil rights and civil liberties had to be made. D.

100. Social Studies

The Due Process Clause guarantees that: A. the National Government will not interfere with Constitutional rights. B. states are not bound to their state constitutions in matters of individual rights. C. states will not deny people any basic or essential

101. pre-algebra

jack brought 3 items that cost 25 dollars each, and five items that cost 40 dollars each. what was the total cost, including 5% sales tax?

102. Math-geometry

(a) translate the argument into symbolic form and (b) determine if the argument is valid or invalid. You may compare the argument to a standard form or use a truth table. If Nicholas Thompson teaches this course, then I will get a passing grade. I did not

103. Chemestry form two

Balance chemical equations to show the reactions that occur when apice of sodium metal is ex posed to atmosphere

104. chemistry

the density of water is 1gm/ml. what is the molarity of 1 drop of water?

105. algebra

Please help f(x) = 3x² + 2 x= 3 my question, do I start by solving x² first then multiply by 3 and adding 2 f(3= 3 * 9 + 2 = 29 or do I multiply first 3*3 =9² +2 = 83 I'm pretty sure we resolve the exponents first but need some help

106. Cal

Find the volume of the solid formed by rotating the region enclosed by y=(e^(2x))+4,y=0,x-0,x=0.4. I tried doing this but got really confused. Really appreciate it if you guys help.Tnks

107. algebra 2

Solve the equation. Give an exact solution. ln(3x - 2) = ln 2 - ln(x - 1)

108. arithmetic

List the terms that complete a possible pattern in each of the following and state whether the pattern is arithmetic, geometric, or neither: (a) 38, 33, 28, 23, 18, … (b) 640, 320, 160, 80, … (e) 1, ___, ___, ___ 25, 36, 49

109. Chemistry

At STP, 461 mL of a gas have a mass of 1.88 g. What is the molar mass of the gas?

110. accounting

Discuss EVA concept, how is EVA determined, Describe how the company can increase EVA, Dicuss why and how EVA relates to financial ratio analysis

111. trig

Verify that each trigonometric equation is an identity tan^2+1/sec Î± =sec Î±

112. science

If u use 4 g of calcium carbonate in excess acid,instead of 2 g.They find that the rate of the reaction increases.why the rate increases?

114. math

how about if the raduis of right circular cone is given and the surface area is given what is the formula? help please?

115. PHYSICS

A 54.0-cm diameter disk rotates with a constant angular acceleration of 2.0 rad/s2. It starts from rest at t = 0, and a line drawn from the center of the disk to a point P on the rim of the disk makes an angle of 57.3° with the positive x-axis at this

116. algebra/trignometry

Verify that each trigonometric equation is an identity tan^2+1/sec Î± =sec Î±

117. math

xsquared-4y squared when x=-16 y=17

118. pre algreba

7-3 (x-5) thxs

119. math

solve the system in interval [o,2π): y=sin^2(x)+cos^2(x) or x+π=cos^-1(y)

120. statistics

This is what my teacher gave us I guess he want us to figture out the question. cost/mile 0.08 normal distribution means=.08 standard deviation=0.2 Car life 5 uniform distribution( minmun=2, max=8 annual milage =900 triangular distribution(min=3700 most

121. chemistry

60 grams of ethyl alcohol, and 40 grams of H2O form a solution, what are the solute and the solvent

122. Chemistry

What is the molarity of a solution containing 40 grams of NaOH in 100 ml of soution

123. Behavioral Science

what is the most divisive issue that is fueling the controversy over Affirmative Action

124. American History

In 1700, which of the following colonies had the largest slave population relative to its overall population?

125. English

Can you please help me express the following concepts in English? Check the word choice, please. 1) My mother wanted to make a great pianist of me. She always reminds me of my inability to play the piano. 2) The English language is made up of a collection

126. Math-geometry

Construct a truth table for (p ^ q) ↔ ~p

127. chemistry

the temperature of a 20.0g sample of a metal(specific heat .03 J/g-C) is raised by 20C. How much heat has been absorbed by the metal?

128. chemistry

what is the substance in a solution that gets dissolved

129. Chemistry

Question: What is the maximum number of liters of HNO3(g) that can be made from 14.88 L of H2O(g) and 10.66 L of NO2(g) at STP? 3 NO2(g) + H2O(g) ==> 2 HNO3(g) + NO(g) I have no idea how to do this. Please help if you can.

130. pre algreba

7-3 (x-5) thxs

131. algebra 2

Solve the equation. If necessary, round to thousandths. 3^(2x + 1) = 27

132. Physics

How does an object's speed affect its aerodynamics?

133. Physics

As a rocket accelerates upward, its thrust remains constant but its acceleration increases. what is the cause of this?