# dave

Popular questions and responses by dave-
## math

Fido weighs 26 pounds more than Fifi. Fifi weighs 12 pounds less than Rover. If the sum of their weights is 71, how much does Fifi weigh?

*asked on February 4, 2017* -
## statistics

A random sample of size 36 is taken from a population with mean 50 and standard deviation 5. Find P( < 51.5).

*asked on July 6, 2012* -
## spanish

Answer the questions negatively, using the imperfect tense. Make sure to include the direct object pronoun when needed. Follow the model. Modelo ¿Juega Daniel al fútbol? No, pero antes lo jugaba. ¿Hablas por teléfono? No hablaba ¿Fue a la playa

*asked on March 31, 2011* -
## Chemistry

Suppose you titrated a sample of sulfuric acid (diprotic acid) with a 0.250 M solution of NaOH. Given the data in the table below, what is the concentration of the sulfuric acid solution?

*asked on December 6, 2016* -
## Social Studies

1. Which of the following apply to fascism? Select all that apply. A rooted in militarism B extreme nationalism C respect for minorities D blind loyalty to the state I think its A,B, and c ----------------------------------- 2. Which of the following best

*asked on February 26, 2017* -
## Math

Find the 999th derivative of cos x. I got sin x.

*asked on October 20, 2016* -
## General Chemistry

A student dissolved 4.00 g of Co(NO3)2 in enough water to make 100. mL of stock solution. He took 4.00 mL of the stock solution and then diluted it with water to give 275. mL of a final solution. How many grams of NO3- ion are there in the final solution?

*asked on October 12, 2010* -
## Chemistry

Calculate the equilibrium constant for the following reaction at room temperature, 25 ∘C: N2(g)+O2(g)→2NO(g)

*asked on June 21, 2013* -
## physics

A uniform pole 7m long and weighing 10kg is supported by a boy 2m from one end and a man 3m from the other end.At what point must a 20kg weight be attached so that the man would support thrice as much weight as the boy?

*asked on June 21, 2018* -
## Math

a geometric progression has a third term of 20 and a sum to infinity which is three times the first term. find the first term

*asked on May 12, 2016* -
## Calculus

Gloria would like to construct a box with volume of exactly 45ft^3 using only metal and wood. The metal costs $15/ft^2 and the wood costs $6/ft^2. If the wood is to go on the sides, the metal is to go on the top and bottom, and if the length of the base is

*asked on November 4, 2015* -
## American History

Which statement best describes the Monroe Doctrine? A. The United States welcomed European involvement in all issues in North America. B. The United States welcomed any European involvement in South America. C. The United States pledged to involve itself

*asked on April 3, 2015* -
## Physics

The initial kinetic energy imparted to a 0.1 kg bullet is 1036 J. The acceleration of gravity is 9.81 m/s2 . Neglecting air resistance, find the range of this projectile when it is fired at an angle such that the range equals the maximum height attained.

*asked on February 27, 2011* -
## Science

Which of these statements regarding enzymes is FALSE?

*asked on February 26, 2007* -
## Physics

A glass bottle full of mercury has a mass 500g. 35°C, 243g of mercury are expelled. Calculate the mass of f mercury remaining in the | bottle. (Cubic expansivity. of mercury . is 1.8×x10^-4 K^(-1), linear . expansivity .of glass is 8.0×10^(-4)k^(-1)

*asked on December 28, 2019* -
## Physics

A dike in Holland springs a leak through a hole of area 0.80 cm2 at a depth of 1.2 m below the water surface. How much force must a boy apply to the hole with his thumb to stop the leak?

*asked on October 6, 2016* -
## Chemistry-Solubility Product

Why does effervescence when the Group 2 anion precipitate is acidified imply the presence of (CO3)2- ?

*asked on April 12, 2009* -
## Math/Statistics

The mean starting salary for graduates in the spring of 2004 was $36,280. Assume that the distribution of starting salaries follows the normal distribution with a standard deviation of $3,300. What percent of the graduates have starting salaries between

*asked on November 29, 2010* -
## Economics

If Mary takes money from her savings account and buys a T-bond from Jody with that money, it's: A. An expansionary fiscal policy. B. An example of contractionary monetary policy. C. An example of expansionary monetary policy D. An example of neutral

*asked on June 24, 2007* -
## Trignometry

Use the appropriate reciprocal identity to find the approximate value of sin θ for the given value of csc θ. Use a calculator. csc θ = 2.15750581

*asked on September 8, 2017* -
## physics

Identify the force that propels a rocket. 1)The rocket is propelled by the reaction force of the exhaust gasses bouncing off the air molecules outside the rocket. 2)The rocket is propelled because the action force of the rocket on the exhaust gases is

*asked on October 18, 2016* -
## Biochem

If .1ml of serum, 5ml of reagent and 4.9ml of distilled water are mixed together what is the dilution of the serum in the final solution

*asked on March 23, 2014* -
## trig

how do i set this problem up? Find tan (s + t) given that sin s = 1/4, with s in quadrant 2, and sin t = -1/2, with t in quadrant 4.

*asked on May 2, 2010* -
## physics help!!!

In February 1955, a paratrooper fell 365 m from an airplane without being able to open his chute but happened to land in snow, suffering only minor injuries. Assume that his speed at impact was 60 m/s (terminal speed), that his mass (including gear) was 90

*asked on March 26, 2010* -
## Finance

At what rate must $500 be compounded for it to grow to 1079.46 in 10 years? 8 percent? i think

*asked on November 12, 2009* -
## physics

A rugby player runs with the ball directly toward his opponent's goal, along the positive direction of an x axis. He can legally pass the ball to a teammate as long as the ball's velocity relative to the field does not have a positive x component. Suppose

*asked on September 28, 2009* -
## physics/chem

(a) What equal positive charges (in Coulombs) would have to be placed on two celestial objects with masses 9.40 x 1027 and 1.99 x 1022 kg to neutralize their gravitational attraction? (b) What mass of hydrogen would be needed to provide the positive charge

*asked on March 31, 2008* -
## Economics

Will the aggregate quantity of goods and services demanded become more sensitive or less sensitive to changes in the price level if an economy becomes closed (that is, as foreign trade disappears)? In terms of the AD/AS diagram, will the AD curve become

*asked on June 18, 2007* -
## chemistry

For the reaction 2Na(s)+Cl2(g)→2NaCl(s)2Na(s)+Cl2(g)→2NaCl(s), how many grams of NaCl could be produced from 20 L of Cl2Cl2 (at STP)?

*asked on March 3, 2017* -
## Calculus

Use Simpson's rule with n = 4 to approximate. Keep at least 2 decimal places accuracy. Integrate: (cos(x))/(x) x=1 to 5

*asked on May 3, 2016* -
## Physical Science

The main difference between the internal combustion engine and the diesel engine is that the diesel engine A. does not have a crankshaft. B. does not utilize pistons. C. has no connecting rods. D. has no ignition system. pretty sure its d

*asked on February 27, 2015* -
## Math - Business Stats. PLS HELP!

help pls!!! thank u in advance, i appreciate it greatly Alex, Alicia, and Juan fill orders in a fast-food restaurant. Alex incorrectly fills 20% of the orders he takes. Alicia incorrectly fills 12% of the orders she takes. Juan incorrectly fills 5% of the

*asked on October 10, 2014* -
## chem

A 6.75-g sample of gold (specific heat capacity = 0.130 J/g °C) is heated using 55.8 J of energy. If the original temperature of the gold is 25.0°C, what is its final temperature?

*asked on March 14, 2013* -
## physics

A ball is released from a hot air balloon moving downward with a velocity of -10.0 meters/second and a height of 1,000 meters. How long did it take the ball to reach the surface of Earth? Given: g = -9.8 meters/second2.

*asked on July 10, 2012* -
## physics

hi, reading over momentum notes and i just want to clarify a few things. if i had a system containing a cart that was moving (cart 1) and then a cart that was stationary (cart2)would there be any net external force acting on the system between the initial

*asked on November 13, 2011* -
## chemistry

The heat of vaporization of a substance is 2900 J/g at its boiling point of 313C. How much of this substance can be vaporized if 58700 J of energy are available?

*asked on January 17, 2011* -
## Trigonometry

You observe a plane approaching overhead and assume that its speed is 700 miles per hour. The angle of elevation of the plane is 16° at one time and 58° one minute later. Approximate the altitude of the plane

*asked on November 22, 2010* -
## Physics Help Please!

If the price of electrical enegy is $0.10 per kilowatt *hour, find the cost of using electrical energy to heat the water in a 12.0m * 9.00m * 1.5m swimming pool from 15 degrees C to 27 degrees C. So the change in temperature is 285.15 , the volume is

*asked on April 6, 2010* -
## Computers

Show what the final output of this function will be. The answer will be in the form x * Z - y Private Function F(x as Int, y As Int, z as Int) If (y = 1) then Return 2 Else Return x * Z - y + F(x-1,y-1, z) End If End Function

*asked on August 27, 2009* -
## physics/chem

Calculate the number of coulombs of positive charge in 261 cm3 of (neutral) water. (Hint: A hydrogen atom contains one proton; an oxygen atom contains eight protons.)

*asked on March 31, 2008* -
## calculus : related rates

a balloon rises at a rate of 3 meters per second from a point on the ground 30 meters from an observer. find the rate of change of the angle of elevation of the balloon from the observer when the balloon is 30 meters above the ground... so i drew a small

*asked on November 5, 2007* -
## Economics

Which of the following statements would come from someone classified as unemployed? A. I'm not working. I had three interviews this week, and I'm trying to find a job. B. I haven't had a job in a year, and I stopped looking for a job nine months ago. C.

*asked on June 13, 2007* -
## Chemistry

ELement A has a valence electronic structure of ns2np1. Element B has the valence electronic structure of ns2np5. Write a formula for the compound that would be formed from elements A and B. Element A has three electrons to lose to make the last shell

*asked on April 19, 2007* -
## Science

During the process of photosynthesis, solar energy is converted into: a. chemical energy. b. heat energy. c. thermal energy. d. mechanical energy. e. nuclear energy. a

*asked on February 26, 2007* -
## Math

"Cab companies often charge a flat fee for picking someone up and then charge an additional fee per mile driven. Pick a U.S. city and research the rates of two different cab companies in that city. Find companies that charge different amounts per mile and

*asked on November 13, 2017* -
## Algebra

Given that $x^n - \frac1{x^n}$ is expressible as a polynomial in $x - \frac1x$ with real coefficients only if $n$ is an odd positive integer, find $P(z)$ so that $P\left(x-\frac1x\right) = x^5 - \frac1{x^5}.$

*asked on June 5, 2017* -
## Chemistry

Nitrogen monoxide reacts with chlorine gas according to the reaction: 2NO (g) + Cl2 (g) â‡” 2NOCl (g) Kp = 0.27 at 700 K A reaction mixture initially contains equal partial pressures of NO and Cl2 . At equilibrium, the partial pressure of NOCl is 115

*asked on April 4, 2017* -
## physics

Identify the force that propels a rocket. 1)The rocket is propelled by the reaction force of the exhaust gasses bouncing off the air molecules outside the rocket. 2)The rocket is propelled because the action force of the rocket on the exhaust gases is

*asked on October 18, 2016* -
## Chemistry

What set of hybrid orbitals is used by Xe in XeO3F2? dsp2 d2sp3 sp3 dsp3 d2sp

*asked on March 2, 2016* -
## Math

Lim sin(60-x)/2cosx-1 x approaches 60

*asked on January 2, 2016* -
## math

Consider the equation f(x)= -2 sqrt(X+3). List in order the transformations applied to the parent function.

*asked on October 9, 2015* -
## World History

Regarding Indonesia, which of the following statements is false? A. Indonesia was formerly the British East Indies. B. The first head of Indonesia was Sukarno. C. The first leader of Indonesia was Suharto. D. Indonesia was formerly the Netherlands East

*asked on March 10, 2015* -
## Electricity and Electronics

A complete circuit contains two parallel-connected devices and a generator for providing the electromotive force. The resistance of the first device is 12 ohms, the resistance of the second device is 4 ohms, and the voltage developed by the generator is 40

*asked on February 24, 2015* -
## Physics

The force required to stretch a spring varies directly with the amount the spring is stretched. A force of 29 pounds is needed to stretch a spring 39 inches. How much force is required to stretch the spring 27 inches? Answer in units of lb

*asked on December 6, 2014* -
## O-Chem

Draw the mechanism of the reaction of (E)-stilbene with Br2.

*asked on November 13, 2014* -
## Precal

The point (r,theta) in polar coordinates is (7,5) in rectangular coordinates. What is the point (2r, theta + pi/2) in rectangular coordinates? So I tried this problem and got r = sqrt(74). But while finding the value of theta, I got it equal to cot(5/7)

*asked on August 9, 2014* -
## Chemistry

2CH3CH2CH2OH(l)+9O2(g)→6CO2(g)+8H2O(g) I have to find the delta G delta G of CH3CH2CH2OH(l)=−360.5 KJ/Mol delta G of O2(g)=0 KJ/Mol delta G of CO2(g)=−394.4 KJ/Mol delta G of H20(g)=−228.6 KJ/Mol I keep getting -3426.2 KJ/Mol but its not correct.

*asked on June 21, 2013* -
## I NEED MATH HELP

$24,000 is invested for 3 years with an APR of 2% and daily compounding. Balance in the account after 3. years is $ ___

*asked on January 27, 2013* -
## Math

A piece of aluminum with an unknown mass ios at 85c and is placed in a 2.00 liters of water at 25.0c. The final temperature becomes 33c. What is the mass of aluminum?

*asked on November 8, 2012* -
## Prob and Stats

The Roper Organization conducted identical surveys 5 years apart. One question asked of women was Are most men basically kind, gentle, and thoughtful? The earlier survey revealed that, of the 3,000 women surveyed, 2,010 said that they were. The later

*asked on September 5, 2011* -
## College math

What is the probability without replacement of drawing at least one ten (52 card deck)?

*asked on May 2, 2011* -
## Math

What is the sum of the measures of the interior angles of an 11-side polygon?

*asked on January 12, 2011* -
## math

a baseball team buys 15 bats for $405. aluminum bats cost $25 and wooden bats cost $30. how many of each type did they buy? Please show work

*asked on November 6, 2010* -
## Chemistry

A 2.50 gram sample of bronze was dissolved in sulfuric acid. The copper in the sample reacted with sulfuric acid to form copper sulfate. Cu (s) +2 H2SO4 (aq) -> CuSO4 (aq) +2 H2O (l) The copper sulfate formed in this reaction was mixed with I to form

*asked on October 31, 2010* -
## algebra

While shopping, Jill spent six times as much as Nan. If they spent a total of $112, how much did each person spend?

*asked on October 24, 2010* -
## Psychology

• Find a peer reviewed article which discusses the effects of optimism on physical and psychological health. • Write a 1400 to 1600-word paper summarizing the article and stating your opinion on the validity of the study or studies.

*asked on August 19, 2010* -
## SCIENCE 1

The van der waals equation incorporates corrections to the ideal gas in order to account for the properties of real gases one of the correcctions accounts for A.attractions between molecules B.the quantum behavior of molecules C.that average kinetic energy

*asked on May 11, 2010* -
## economics

if production displays economies of scale, the long run average cost curve is: a) upward sloping b) above the short run average total cost curve C0 below the long run marginal cost curve d) downward sloping

*asked on October 5, 2009* -
## math

The acceleration of a particle at a time t moving along the x-axis is give by: a(t) = 4e^(2t). At the instant when t=0, the particle is at the point x=2, moving with velocity v(t)=-2. Find the position of the particle at t=1/2 if you could show me how to

*asked on February 23, 2009* -
## physics/chem

n Fig. 21-41, three identical conducting spheres initially have the following charges: sphere A, 7Q; sphere B, -8Q; and sphere C, 0. Spheres A and B are fixed in place, with a center-to-center separation that is much larger than the spheres. Two

*asked on March 31, 2008* -
## math

how do you find the reference angle of csc,sec, cot? for example: csc theta= 2 times square root of 3 / 2

*asked on February 4, 2008* -
## Purchasing Power of Income/ Economy

We use the _________ to determine the purchasing power of income. A. Interest rate. B. Real GDP. C. CPI. D. GDP. E. None of the above. Check this site for your answer. http://www.bls.gov/cpi/

*asked on June 14, 2007* -
## History

Could someone please find me a website that has great information on Business enterprise in America so I can make a timeline on it. Specific dates that I need are 1906, 1913, 1914 , 1930, 1939. I would greatly appreciate it. This site seems to have the

*asked on April 29, 2007* -
## Algebra II

Our current assignment is to find the LCM, Least Common Multiple of two polynomials. I think I'm doing it right but I'm not quite sure. For the first question: 2t^2+t-3, 2t^2+5t+3 I have 2t^2+t+3 as the LCM. Is this correct or can somebody step me through

*asked on February 15, 2007* -
## AP Chemistry

(a) What is the pH of a 2.0 molar solution of acetic acid. Ka of acetic acid = 1.8 x 10¯5 (b) A buffer solution is prepared by adding 0.10 liter of 2.0 molar acetic acid solution to 0.1 liter of a 1.0 molar sodium hydroxide solution. Compute the hydrogen

*asked on February 13, 2007* -
## Math

1. Let T = {a, b, c, d}. a. Find an example of a relation of this set that is transitive, but neither reflexive nor symmetric. b. Find an example of a relation on this set that is both transitive and symmetric, but not reflexive.

*asked on April 24, 2020* -
## Chemistry

What intermolecular forces exist in dichloromethane, n-pentanol, and toluene besides London Dispersion Forces?

*asked on April 9, 2020* -
## Maths

The height h, in metres, of a ball thrown from a cliff can be modelled by the function with the rule h(t) = 20+15t-5t^2, where t less than/equal to 0 is the time measured in seconds. a) find the initial height of the ball b) find the time at which the ball

*asked on March 11, 2020* -
## math

: Find the value of x in the figure.

*asked on June 11, 2019* -
## Math

A is partly constant and partly varies as b when A is equal to 15 B was 2 when is equal to A 45 is B equal to 8

*asked on March 9, 2019* -
## Calculus AB/BC

What's the purpose of finding derivatives? I don't understand why you would need to find a derivative, which is the tangent of the slope of a point on a graph, to find something like "How far did Bob fall". Confusing. Please help. Thank you!

*asked on November 2, 2017* -
## Math

Solve the indefinite integral of 1/sqrt(x^2+2x+5). I solved it all out by completing the square and then trig sub and then drawing a triangle to go back to x variable and got: ln |(sqrt(x^2+2x+5)/2 + (X+1)/2 ) | but the book answer is: ln |(sqrt(x^2+2x+5)

*asked on October 10, 2017* -
## Math

Solve the indefinite integral of 1/sqrt(x^2+2x+5). I solved it all out by completing the square and then trig sub and then drawing a triangle to go back to x variable and got: ln |(sqrt(x^2+2x+5)/2 + (X+1)/2 ) | but the book answer is: ln |(sqrt(x^2+2x+5)

*asked on October 10, 2017* -
## Math

Evaluate the integral from [sqrt(pi/2), sqrt(pi)] of x^3*cos(x^2) by first making a substitution and then using integration by parts. I let u = x^2 and du= 2x dx but then it doesn't equal that in the equation?

*asked on September 29, 2017* -
## Chemistry

A 10.0000 g block of aluminum is heated and placed in a stream of oxygen gas, resulting in the formation of aluminum oxide on the surface of the block. The block is cooled and weighed and found to have a mass of 11.6471 g. The block is then placed in a

*asked on September 26, 2017* -
## Math

Evaluate the integral of (x^3 + x^4*tanx) from [-pi/4, pi/4] How do we know which one to let equal to u in order to start this whole process? The answer in the book is 0.

*asked on September 13, 2017* -
## Ed Tech

To edit the text in a smartart graphic, what must be done first ?

*asked on August 29, 2017* -
## math

a rectangular plate 120 ft long and 80 ft wide is submerged vertically with the longer edge in the surface of the water find the force on one side of the plate

*asked on May 16, 2017* -
## mechanics

a rectangular plate 120 ft long and 80 ft wide is submerged vertically with the longer edge in the surface of the water find the force on one side of the plate

*asked on May 16, 2017* -
## Calculus

The region enclosed by the graph e^(x/2), y=1, and x=ln(3) is revolved around the x-axis. Find the volume of the solid generated. I don't understand if we have to use the washer method or the disk method for this one because when I drew it out on a graph

*asked on March 1, 2017* -
## Social studies

Which of the following factors was most responsible for an unequal distribution of wealth? A There was an increase in business profits. B Wages were not keeping pace with profits of business owners. C Wages were not keeping pace with profits of business

*asked on February 23, 2017* -
## Physics

Which of the following is an element? H2O Hydrogen Carbon dioxide A supernova

*asked on October 7, 2016* -
## physics

The contestants at a cycling race travel around a 0.5km radius track. The peloton travels 33 laps in 1 hour to complete the race. What is the total angular distance they have traveled? On the first lap, they start from rest and after traveling ½ the

*asked on June 30, 2016* -
## Math

A pharmaceutical salesperson receives a monthly salary of $2500 plus a commission of 7 percent of sales. Write a linear equation for the salesperson monthly wage in terms of monthly sales.

*asked on June 7, 2016* -
## chem

Determine the mass of oxygen in a 7.2-g sample of Al2(SO4)3

*asked on April 18, 2016* -
## Math

Can somebody show or explain this to me: Change 6 2/3% to fraction and .6 1/3 to a decimal or fraction.

*asked on February 13, 2016* -
## Physics

A watertight car is submerged under water. What force is required to open a door of area 1.12 m2 if the average depth of water at the door is 1.50 m?

*asked on December 8, 2015* -
## math

5 inches is what fraction of a foot? A. 1/3 B. 1/2 C. 5/12 D.5/24 my answer is C. is it correct?

*asked on October 27, 2015* -
## Math

Find the area of a triangle with base of 15 m and altitude of 12 m

*asked on August 6, 2015* -
## Physics (optics)

A ray of light traveling in air strikes the midpoint of one face of an equiangular glass prism (n = 1.74) at an angle of exactly 30.0â—¦ Trace the path of the light ray through the glass and find the angle of incidence of the ray at the bottom of the

*asked on May 12, 2015*