# Posts by laura

Total # Posts: 1,250

**math**

Find the indicated term of the geometric sequence.

**Physics (I have a test tomorrow) **

What power is required to accelerates a 1980kg car from 30km/h to 70km/h against a constant force of resistance of 750N over a distance of 85m. Thank you for your help!

**Physics **

A tow truck pulls a car from rest onto a level road. The tow truck exerts a horizontal force of 1500 N on the car. The frictional force on the car is 810 N. Calculate the work done by each of the following forces on the car as the car moves forward 12 m: (a) the force of the ...

**Physics (I have a test tmrw) **

The half-life of Strontium-90 is 28 a. If 60 g of this isotope is currently in a sample of soil, estimate the amount in the same sample 84 a later. So I did a=60g(1/2)^84/28 But I don't know if thats correct. Thank for your help!

**chemistry **

some pollutants in natural waters such as heavy metal and organic compounds would be classified as having low solubility.what are some origins of pollutants in natural waters? if some are low solubility compounds, why are these a problem? Hello, I just don't understand ...

**chemistry (I have a test tomorrow) **

4 Ag + 2 H2S + O2 = 2 Ag2S + 2 H2O a) What mass if silver sulfide is formed from the reaction of 0.120g of silver? b) What mass of hydrogen sulfide is needed in the same process? So I understand a, and I found the answer to be 0.138g. For b the text book says the answer is 0....

**Math**

Sean spent 1/5 of his money in the shop and 7/10 IN another what fraction of his money is left

**Calculus II**

I need to find if the summation of (n^4)/(n^10 + 1) is convergent or divergent from n=1 to infinity. I tried splitting it up into two sums, one being 1/n^6, which would be convergent because p=6>1, and then the other being n^4, but I'm not sure how to know if this is ...

**Physics **

A 240 kg roller coaster car Rolls over the crest of the roller coaster with a speed of 2.2m/s.if it falls through a vertical height of 12m down the tracks to the bottom of a trough, how fast will it be travelling? So here's what I did but I don't think it's right: ...

**Physics **

A 55kg arrow is fired vertically upward at a speed of 42m/s. It rises upwards, then drops and lands on the ground. If it lodges itself 12cm in the ground, determine the average force that the ground exerts on the arrow This is what I've done but I don't think it's ...

**Financial maths year 9**

Sophie borrowed $2000 at a simple interest rate of 15% for 3 years to repay the loan and has $900 in interest. If Sophie's interest was calculated at the same rate on the balance owing, how much would she have owed after 6 months if she repaid $40 per month? Give your ...

**Maths**

How many weeks will it take for 50 000 to earn 1500 in interest if the rate is 6% p.a.

**Laws of Physics**

A block and tackle has a velocity of 6 and it is being used to raise a mass of 68 newtons through 3 meters. The efficiency is 60% Calculate the amount of energy needed to lift the mass through 3 meters and calculate the amount of energy that was put into the system and the ...

**Math**

An investment is initially worth $11,100. Write a formula for the function V(t) representing the value of this investment after t years in each of the following situations: A) The value decreases by $889 per year. B) The value increases by $899 per year.

**Chemistry**

You add 3.5 L of an HCl solution of unknown concentration to 2.0 L of 0.5 M HCl and 4.5 L of water. The final concentration of HCl was 1.5 M. What was the unknown concentration of the initial HCl solution?

**math**

a bag of chips weigh eight ounces how many bags of chips weigh 12 pounds

**applied calculus **

From a height of 25 meters a ball is thrown vertically upwards at a velocity of 5 meters per second. a.What time in seconds will the ball reach its maximum height? b.What is its maximum height? c.When will the ball strike the ground? d.What will be the ballâ€™s...

**Math**

At what point of the curve y= x^4 is the normal line parallel to 2x + y = 3? Find the equation of the normal line.

**Pre Calc**

The Department of Foreign Languages of a liberal arts college conducted a survey of its recent graduates to determine the foreign language courses they had taken while undergraduates at the college. Of the 500 graduate 207 had at least one year of Spanish. 171 had at least one...

**Pre Calc**

Evaluate the quantity. 4 · P(4, 4) · C(9, 5)

**Pre calc**

Find the point of intersection of the pair of straight lines. 2x + 4y = 19 ?3x + 3y = 3

**pre calc**

Find the point of intersection of the pair of straight lines. y = ?5x ? 4 ?y = 6x + 3

**Physics Equilibrium**

A table is supported against a wall forming an angle with the vertical. The coefficient of static friction between the table and the floor is (?e). The frictional force of the wall on the board may be neglected. Find an expression for the maximum value that the angle can take ...

**Math Help**

Given the functions of f(x)=(x-3)/(x9), g(x)=9x+3, find (gof)(x).

**Chemistry**

How do orbitals on individual atoms interact and change when covalent bonds form in molecules?

**math algebra**

The amount A, of 70 grams of a certain radioactive material remaining after t years can be found by the equation A=70(0.62)^t. When will 10 grams remain?

**math algebra**

the product of two consecutive even numbers is 440. What is the sum of the numbers?

**Math Logs**

logbase4(x+5)=3+logbase4(x-2) Tried so many times please help!

**math algebra**

The lengths of the three sides of a right triangle are given by three consecutive even integers. Find the lengths of the tree sides.

**physics**

a simple pendulum of lengh l,the mass of whose bob is m,is observed to have a speed v0 when the cord makes an angle theta0(0<theta<pi/2).In terms of g and the foregoing given quantities,determinate the least value v2 that v0 could have if the cord is to achieve a ...

**physics**

a simple pendulum of lengh l,the mass of whose bob is m,is obseved to have a speed v when the cord makes an angle with the vertical.Determine the least value v2 that v could have if the cord is to achieve a horizontal position during the motion

**inverses**

its the inverse of A(X) = 7x^2

**inverses**

You have 700 sq ft of plywood to make the stage floor. Use A^-1(x) to find the dimensions of both the runway and the main part of the stage. main stage is a rectangle and runway is a square. length of the main stage is 3x o f the runway, the width of the main stage is 2x the ...

**runways and inverses!**

what does that mean? thats the question. i need to find the dimensions of both the runwway and the main part of the stage

**runways and inverses!**

You have 700 sq ft of plywood to make the stage floor. Use A^-1(x) to find the dimensions of both the runway and the main part of the stage. main stage is a rectangle and runway is a square. length of the main stage is 3x o f the runway, the width of the main stage is 2x the ...

**math**

your school is putting on a prom fashion show, and you are in charge of building a platform to serve as a stage. Main stage is a rectangle and the runways is a square. the length of the main stage is three times the length of the runway and the width of the main stage is two ...

**Algebra**

Christy drove at an average speed of 55 mi/h from her home in San Francisco to visit her sister in Tucson. She stayed in Tucson 10 hours, and on the trip back averaged 35 mi/h. She returned home 50 hours after leaving. How many miles is San Francisco from Tucson? a) Write an ...

**math**

according to arrow impossibility theorem ,it is possible for voting method to satisfy every fairness criteria that the texbook discussed?

**math algebra**

if f(x) = x+1/x^2-9 and g(x) =x/x-3, find a) domain of f(x) b) domain of g (x) c) (f+g) (x) d) the domain of (f+g) (x)

**math**

A group of people were asked if they had run a red light in the last year. 433 responded "yes", and 424 responded "no". Find the probability that if a person is chosen at random, they have run a red light in the last year.

**math**

each letter represents a different number find the value of p,o and f that will make this puzzle true. pop+of=opp

**stats**

The coding department of Community Physician’s Clinic is interested in purchasing a software program that will edit claims before they are sent to the Billing Office. The license fee for the software is $60,000 per year. The software is expected to reduce the number of ...

**stats**

In September, the hospital had three coders who coded 1,500 inpatient records, and 22 of the records failed the quality screens. a. What is the average number of records coded by each coder? b. What was the average number of records coded each working ...

**Physics**

Commercial airplanes are sometimes towed out of the passenger loading area by a tractor. The 1800 kg tractor exerts a force of 1.75 104 N backward on the pavement, and the system experiences forces resisting motion that total 2400 N. (a) If the acceleration is 0.250 m/s2, what...

**College Algebra**

compute the cost to remove 25% of the air pollutants

**chemistry**

How can values of heats of formation found in tables be used to calculate heats of reactions? I am having a really hard time understanding this.

**chemistry**

How much energy is required to make H2O(g) from H2O(l)? Basically this deals with bond energies and heats of formation. But I'm not sure how to find it

**Math**

Let C=f(q)=450+0.2q give the cost in dollars to manufacture q kg of a chemical. a) Which of the following statement(s) correctly explain the meaning of f^(−1)(C) b)Find a formula for f^(−1)(C)=

**Chemistry**

Five year old Andrew weighs 45 lbs and requires insulin. His doctor has prescribed 0.150 units of insulin/kg body weight/hr while he is in the hospital. The insulin bottle you have possesses a concentration of 20.0 units/15.0 ml and all must be given. Give all answers to three...

**Math**

False because 0 does not equal 2. If it was just zero is less than 2 it would be true.

**chemistry**

is this statement true? More heat is needed for vaporization of a liquid compared with melting a solid of the same substance.

**chemistry**

If you transfer 5 J of energy to 1 g water and to 1 g ethanol, each starting at the same temperature which would have a higher temperature at the end? Water or ethanol? or will they have the same temperature at the end?

**Math**

Rewrite the expression 2logx−3log(x^2+1)+4log(x−1) as a single logarithm logA. Then the function

**Math**

Solve for x 8⋅4^2x−4=53

**Math**

The cost (in dollars) of producing x air conditioners is C=g(x)=560+40x. Find a formula for the inverse function g−1(C).

**Chemistry help please!**

Why does a clear, saturated solution of PbI2 form a yellow precipitate when a small amount of KI is added to the solution? A. KI is insoluble in PbI2. B. PbI2 is always insoluble in water. C. Adding KI is like adding I-, which drives the reaction toward the formation of I-. D...

**Chemistry please help!**

What happens to the following reaction at equilibrium if the pressure is decreased? 2H2(g) + O2(g) 2H2O(g) A. The equilibrium shifts left because Q > K. B. The equilibrium shifts right because Q < K. C. The equilibrium shifts left because Q < K. D. The equilibrium ...

**Chemistry**

pH indicators change color at their _____. The pH at which the color change happens for a particular indicator molecule depends on its: A. pKa; concentration. B. pKa; Ka or Kb. C. equivalence point; Ka or Kb. D. equivalence point; concentration. Is the correct answer A?

**Chemistry**

Given the reaction: Cu2+(aq) + S2-(aq) CuS(s) What will happen (a) if CuSO4(aq) is added? And (b) if Na2SO4(aq) is added? A. (a) Nothing; (b) Less product will form B. (a) Less product will form; (b) Nothing C. (a) Nothing; (b) More product will form D. (a) More product will ...

**Chemistry**

At a high temperature, the equilibrium constant for the decomposition of hydrogen iodide is 65.0. If the initial concentration of HI is 1.60 M, what is the concentration of hydrogen at equilibrium? 2Hl(g) H2(g) + I2(g) A. 1.42 M B. 0.753 M C. 0.240 M D. 0.802 M I think that ...

**Chemistry**

The pH of your swimming pool is found to be 6.89. What is the concentration of H+ ions in the pool? A. 7.76 × 106 M B. 0.84 M C. 1.29 × 10-7 M D. 1.29 × 107 M

**Chemistry**

Which of the following pairs would make a good buffer? A. H2C2O4 and HC2O4- B. HNO3 and NO3- C. NaOH and NaCl D. HCl and NaOH Would it be C? I think I remember learning about these in a lesson about buffers, hence why my instinct is to go with C...

**Chemistry**

A solution has [OH-] = 3.5 × 10-6. Based on that, what must be true about this solution? A. It is an acidic solution. B. It is a strong base. C. It is a strong acid. D. It is a basic solution.

**Chemistry**

When are more products of a reaction available initially than at equilibrium? A. K = 0 B. Q < K C. Q = K D. Q > K

**English**

The subject,verb and object in " great people endure criticism without resentment"

**Chem2**

The vapor pressure of water (at 50.0 o C) is lowered by 17.0 torr when 36.1 g of an unknown non-electrolyte is added to 65.56 g water. Determine the molecular weight of the unknown. Density solution = 1.05 g/mL Vapor pressure H2O @ 50oC = 92.5 torr

**math homework help**

write the equation of the ellipse that has its centre at the origin with focus (0,4) and vertex at (0,7)

**math**

solve the system of equations algebraically for real values of x and y { x+y=16 x^2+y^2=128 a. (6,6) b. (8,6) c. (9,8) d. (8,8) e. no solution

**math**

find the equation of the hyperbola with vertices (4,0), (-4,0) and focus (7,0)

**math**

any sound from one focus of an ellipse reflects off the ellipse directly back to the other focus. This property explains whispering galleries such as Statuary Hall in Washington DC. Imagine a whispering gallery in the shape of a semi-ellipse. The distance between F and F is 28...

**math help please?!**

Find all (a) minors and (b) cofactors of the matrix [ -3 2 -8 ] 3 -2 6 -1 3 -6

**math help please?!**

Solve the system by Gauss - Jordan elimination. { 1/3 x + 3/4 y - 2/3 z = -8 x + 1/2 y + 1/3 z = 18 1/6 x = 1/8 y - z = -24 a. (−6, 8, −24) b. (−6, −8, −24) c. (0, 8, −24) d. (6,8,24) e. (6, −8, 24)

**math help please?!**

An object moving vertically is at the given heights at the specified times. Find the position equation s = 12 at^2 + v (small o) t + s (small o) for the object. At t = 1 second, s = 161 feet At t = 2 seconds, s = 98 feet At t = 3 seconds, s = 3 feet a. s=−8t^2−t&#...

**math**

Find A - B A = [ 3 7 8 ] B = [ 2 2 6 ] 7 9 3 6 7 8 7 9 9 5 8 6

**math**

Find A + B A = [ 5 5 7 ] B = 4 9 7 3 8 6 9 2 6

**math**

Solve the system by Gauss - Jordan elimination. { 1/3 x + 3/4 y - 2/3 z = -8 x + 1/2 y + 1/3 z = 18 1/6 x = 1/8 y - z = -24 a. (−6, 8, −24) b. (−6, −8, −24) c. (0, 8, −24) d. (6,8,24) e. (6, −8, 24)

**math**

Find values of x and y, if any, that will make the matrices equal. [ x y ] = [ 3 5 ] 1 9 1 9 a. x=-3,y=-5 b. x=5,y=3 c. x=-3,y=5 d. x=3,y=5 e. no solution

**math**

An airplane flying into a headwind travels the 1650-mile flying distance between two cities in 3 hours and 18 minutes. On the return flight, the distance is traveled in 3 hours. Find the airspeed of the plane and the speed of the wind, assuming that both remain constant.

**chem**

What will be the result of a reaction if its enthalpy change is positive, its entropy change is negative and Gibbs free energy is positive? A. Never spontaneous B. Nonspontaneous, if the temperature is low C. Spontaneous, if the temperature is high D. Always spontaneous

**Math**

The answer options I get are either a. 0, pi/3 b. 0, pi/6, pi/3, pi/2 which one would you say suits best?

**Math**

In the interval 0 'less than or equal to' x 'less than or equal to' pi find the values that satisfy the equation cos 2x - sin x = 0

**Math**

Tony visits the local fair and sees one if therides, the ferris wheel. The ferris wheel has a diameter of 50 feet and is on a platform of 4 feet. if it takes 12 seconds to make one full revolution, what is the equation of the height of a person on the ferris wheel at any time...

**Math**

Thank you. Can you explain to me the difference between ( and [ ?

**Math**

Let f(x)= 2x - 1, g(x)= 3x - 2. Find the domain of the function,(f + g)(x)

**Math**

Find the M is the midpoint of the line segment PQ, what is the coordinates of point Q? P (4, 5), M (-2, -3)

**math**

find the trigonometric form of the complex number - (square root) 3 + i

**math**

find the trigonometric form of -12-12(square root)3i a. 24(cos2pi/3 + isin 2pi/3) b. 24(cos4pi/3 + isin 4pi/3) c. 12(cos 4pi/3 + isin 4pi/3) d. 12(cos12pi/3 + isin 2pi/3) e. 12(squareroot) 2 (cos4pi/3 + isin 4pi/3)

**math**

find the standard form of the complex number shown below 9(cos 11pi/6 + isin 11pi/6) a. 2/9 - 2(squareroot)3/9 i b. -4(squareroot)3/9 + 4/9 i c. 9/2 - 9(squareroot)3/2 i d. 9(squareroot)3/2 - 9/2 i e. -9(squareroot)3/4 - 9/4 i

**Physics**

A cube of side L is place in a uniform electric field E = 3200 N/C. What is the net flux through the cube. Assume the electric field lines are parallel with the edges of the cube. Make sure you know why this is the answer. I know its not perpendicular or at an angle So if it...

**statistics**

A coin is biased so that the probability of obtaining a head is 2/3. The coin is tossed four times. Find the probability of obtaining exactly two heads.

**Language A**

How about the third one?? And sorry about that

**Language A**

Selecting 1: There's good news and bad news about grizzly bears in the American West. The good news? Their numbers have been increasing in recent years. In 1975, grizzlies made the threatened-species list under the federal Endangered Species Act. The bad news? Some ...

**Language A**

1: There's good news and bad news about grizzly bears in the American West. The good news? Their numbers have been increasing in recent years. In 1975, grizzlies made the threatened-species list under the federal Endangered Species Act. The bad news? Some politicians want ...

**Language A**

how does the author of selection 1 express his or her point of view differently than the author of selection two? author of selection one agrees with abandoning federal protection of grizzly bears author of selection one believes that the increase in grizzly bear population ...

**Civics**

Thank you :)

**Civics**

Beginning in 1995, most countries in the European Union started to switch to a common currency. The values of different European currencies were linked to the euro. Countries in the European Union could then trade without converting currency. Why would adopting a common ...

**algebra**

294 round to ten

**algebra**

is that the answer

**algebra**

A house has increased in value by 38% since it was purchased. If the current value is $483,000 , what was the value when it was purchased?

**Calculus**

I figured out the answers.