Saturday

July 4, 2015

July 4, 2015

Total # Posts: 98

**math derivatives**

An architect is designing a rectangular building in which the front wall costs twice as much per linear metre as the other 3 walls. The building is to cover 1350 m2. What dimensions must it have so that the costs of the walls is a minimum? write a formula using derivatives
*June 6, 2015*

**Derivatives Instantaneous rate of change**

The electric field E at a distance r from a point field is E =K/r^2 where k is a constant. Find an expression for the instantaneous rate of change of the electric field with respect to r.
*June 3, 2015*

**Math natural logarithms**

The efficiency e of a gasoline engine as a function of its compression ratio r is given by e =1− r^(1−γ) , where γ is a constant. Find γ for e = 0.55 and r = 7.5
*May 16, 2015*

**math**

Assume the brakes of an automobile produce a constant deceleration of k ft/sec^2. Determine what k must be to bring an automobile traveling 60 mph to a rest in a distance of 100 ft from the point where breaks are applied? With the same k, how far would a car traveling 30mph ...
*April 15, 2015*

**science**

If a car has a constant acceleration of 4 m/s², starting from rest, how far has it travelled by the time it reaches the speed of 40 m/s?
*March 28, 2015*

**math**

thanks the weebsite is fun
*January 22, 2015*

**math**

how is GCF and LCM different? im in 4th grade and i tried to understand but my mum said shes not sure so please i need help
*January 22, 2015*

**math**

find the exact value cos (-5 pi/ 12)
*January 22, 2015*

**Physics**

At time t = 0, a projectile is launched from ground level. At t = 2.00 s, it is displaced d = 53 m horizontally and h = 54 m vertically above the launch point. What are the (a) horizontal and (b) vertical components of the initial velocity of the projectile? (c) At the instant...
*January 6, 2015*

**math**

Dear Roberta, the answer should be D recall the identity (a-b)^2 = a^2 - 2ab + b^2 Hope it helps Wishing you the best of luck barry
*July 13, 2014*

**math**

Dear Roberta, the answer is D (1/2)(10t) =50,000 (10t) =50,000 /(1/2) 10t= 100000 t = 10000 Hope it helps! Wishing you the best of luck Barry
*July 13, 2014*

**math**

Dear Roberta, Let the number of people be y 100 + 20y = 25 + 25 y 75 = 5y y = 15 So the answer should be B Hope it helps! Wishing you the best of luck, Barry
*July 13, 2014*

**Alegbra**

Dear sharon, 840 x 0.02 = 16.8(decimal number) 16(integer) Hope it helps! wishing you the best of luck Barry
*July 13, 2014*

**Math**

Hi! the question is ¡Ô(4x+1) + ¡Ô(x+1) = 2 Square both sides (¡Ô(4x+1) + ¡Ô(x+1))^2 = 2^2 still remember the identity (a+b)^2 = a^2 + 2ab + b^2 let ¡Ô(4x+1) be a ¡Ô(x+1) be b as a^2 + 2ab + b^2 we can ...
*July 12, 2014*

**Alegbra**

Dear sharon, the first equation y = -7x - 9 slope= -7 y-intercept= -9 the second equation -3y = 21x + 7 y = -7x -(7/3) slope= -7 y-intercept= -(7/3) To determine whether the two lines are perpendicular slope of equation 1 X slope of equation 2 must be -1. But in this case, ...
*July 11, 2014*

**math**

Dear Kyle, the equation of circle let (h,k) be the center of the circle let the radius be r then the equation of circle will be (x-h)^2 + (y-k)^2 = r^2 so according to your equation of circle given the center point= (-5,7)
*July 10, 2014*

**math**

Dear Kyle, Sub (a,3) into the equation 5x + y = 8 5a + 3 = 8 5a = 5 a = 1 Hope it helps! wishing you the best of luck, Barry
*July 10, 2014*

**chem/math**

Dear Ann, 3.88 = 3.74 + log (x/0.1) 0.14 = log (x/0.1) 10^(0.14) = x/0.1 x = 1.38 x 0.1 x= 0.138 These are the calculation steps. I suppose the answer is 0.138 instead of 0.137. Ann,do you mind showing your calculation steps so I can know what is your mistakes during the ...
*July 8, 2014*

**algebra**

Dear Marcus, The answer is 1/(2x^9y^3) since [-10x13y^12]^0 = 1 as there is a rule <y^0 = 1> And the denominator cannot be further simply Hope it helps!
*July 6, 2014*

**Math**

Dear High, The amount that you are going to get =1000 x (1+(0.08/4))^(4x7) =1741.024 For the interest that you are going to get= 1741.024-1000 = 741.024
*July 4, 2014*

**chemistry**

Dear shashank, The chemical formula of FeSo4.7H2O = 55.8+ 32.1+ 16x4 + 7x18 = 277.9 The percentage of water of crystallization= = (7x18)/ 277.9 x 100% = 45.34%
*June 30, 2014*

**Chemistry**

Dear akhmal, mol of sucrose used= 1/(12x12 + 22 + 11X16) = 2.92x10^-3 as 1 mole of sucrose will produce 12 moles of Co2 mol of CO2 produced= (2.92x10^-3)X 12 = 0.035 grams of CO2 produced = 0.035 X (12+32) = 1.54g as 1 mole of sucrose will react with 12 moles of o2 mole of O2 ...
*June 22, 2014*

**chem**

Dear marie, I guess there is no AlO3 existing So do you actually mean aluminium oxide (Al2O3) The balanced equation is 3OH- + AL3+ -------> Al(OH)3 mol of aluminium oxide needed= 98.1 as 1 mole of aluminium oxide required 3 moles of sodium hydroxide to react with mol of ...
*June 22, 2014*

**math**

I= PRT Simple interest = 280 Nigerian naira X 2.5 X 0.03 = 21 Nigerian naira
*June 22, 2014*

**rates**

The amount of petrol required for each Km = 18/90 =0.2L The amount of petrol needed for 200km =0.2x200 =40L
*June 21, 2014*

**maths**

The largest share is 650x(6/13) = 300
*June 21, 2014*

**Chemistry**

Dear Sally, as I have replied you before, I am not sure whether you have checked HCL(aq) + NAOH(aq)---- NACL(s)+ H20(l) Number of moles in the NAOH(aq)= 40/(23+16+1) =1 as 1 mole of HCL will react with 1 mole of the Naoh solution number of mole of HCL required= 1 Still ...
*June 19, 2014*

**Chemistry**

Dear Sally, Here is the balanced equation HCL(aq) + NAOH(aq)---- NACL(s)+ H20(l) Number of moles in the NAOH(aq)= 40/(23+16+1) =1 as 1 mole of HCL will react with 1 mole of the Naoh solution number of mole of HCL required= 1 Still remember that there is a equation mol= g/molar...
*June 19, 2014*

**chemistry**

Dear hifsa still remember there is a formula Molarity= mol/dm cube so ........ 0.5= mole/ (1.25/1000) number of mole= 6.25x10^-4
*June 19, 2014*

**Chemistry**

Dear Brett, molar mass of the HNO3= 1+14+16x3 =63 number of moles of the HNO3 produced in the reaction = 7.5/63 = 0.119 According to the equation provided 3 moles of NO2 will produce 2 moles of HNO3 Thus,number of moles of NO2 required= 0.119/2x3 = 0.179 mass of N02 required= ...
*June 17, 2014*

**Chemisty**

Dear Veronica, number of moles of HNO3 used= 0.602x(23.4/1000) = 0.014 number of mol of Cu used= 0.014/8x3 =5.28255x10^-3 mass of the Cu involved in the reaction = 5.28255x10^-3 x 63.5 = 0.33544g %by mass of Cu = 0.33544/0.411 x 100% = 81.6%
*June 17, 2014*

**Chemistry**

Dear Abdulhafiz the no of mole of the 50ml of ph3 solution= (1x10^-3)x (50/1000) = 5x10^-5 the number of moles in the 50ml of ph5 solution= (1x10^-5) x (50/1000) = 5x10^-7 Total no of moles in the solution = 5x10^-5 + 5x10^-7 = 5.05x10^-5 The molarity of the new soltion = (5....
*June 17, 2014*

**Chemestry**

how to balence an equasion
*June 1, 2014*

**MATH ✿łāCheckłą✿**

3/ (6+5+4+3) = 1/6
*May 4, 2014*

**add maths**

Dear Mandy, Here is the solution log2 0.45 = log2 (9/20) = log2 9 - log2 20 = 2log2 3 - log2 (4x5) = 2h- (log2 4 + log2 5) = 2h-(2+k) = 2h-2-k Hope this helps
*May 3, 2014*

**biology**

I have to do a lab report on the effect of metal ions on enzyme activity One of the questions asked the sources of error and one asked the methods used I got stuck, can you pls help
*April 16, 2014*

**Algebra**

each side of the new area of the garden = 13 since 13x13 = 169 (side x side = area of square) so 13-9 =4m Therefore, 4m should be the answer
*April 4, 2014*

**PreCal**

log(base 3) x*(x-80)=4 3^4 = x(x-80) 81 = x^2 - 80 quadratic equation x= -1(rejected) or 81 x= 81 log properties used= log(base a)b=k a^k=b hope it helps :)
*April 4, 2014*

**PreCal**

log(1/4) = (3x+5)log8 log0.25/log8 = 3x+5 -2/3 = 3x+5 x= -17/9
*April 4, 2014*

**Probability**

1/13
*February 23, 2014*

**Math**

4x4+4x4+4-4x4=?
*June 1, 2013*

**Eng B**

Beyond tone a poet's attitude toward his or her subject reveals to us a poem's? A. theme B. subject C. diction D. structure I think it's A. Literature-Help me Ms. Sue - Ms. Sue, Thursday, July 3, 2014 at 8:35pm I agree. this person must have been really happy! You ...
*May 4, 2013*

**Math**

A manufacturer of soft-drinks advertises that their orange soda as "naturally flavored," although it contains only 5% orange juice. A new federal regulation stipulates that to be called "natural" a drink must contain at least 10% fruit juice. How much pure ...
*January 31, 2013*

**Math**

A pot contains 6 liters of brine at a concentration of 120g/l. How many liters of the water should be boiled off so that concentration of the brine is 200g/l.
*January 31, 2013*

**math**

I have a diagram of an occupied building space within a larger building represented by 49 equal squares but no linear measures for the sides. The space is 120,000 sq ft. how can i estimate the lengths and widths of the floor space with just this information?
*December 13, 2012*

**math-urgent please help**

Newton’s Law of Cooling states that the temperature of a heated object decreases exponentially over time toward the temperature of the surrounding medium. The temperature u of a heated object at a given time t can be modeled by the following function: u(t)=T+(u-T)e^kt K&...
*December 4, 2012*

**math**

you have an unfortunate brush with the law and you are required to spend some time in the penitentiary. (Naturally you have brought your math 30 course notes with you for a bit of light bedtime reading. You also hope to enlighten your fellow inmates with your mathematical ...
*December 4, 2012*

**algebra**

-4x-5=6+3x
*November 5, 2012*

**math**

simplify this expression (3xy)^2(2x^2z)^3
*November 5, 2012*

**Math**

A piece plywood 24 inches wide is cut into strips 2 and a half inches wide, how many strips of this with can be cut. Please help,7th grade.
*October 5, 2012*

**Physics**

A ball was thrown straight up at 26.2 m/s then caught at the same place it was released. How many seconds was it in the air?
*October 4, 2012*

**Physics**

A brick dropped from a roof hits the ground 4.14 seconds later. How high (in m) was the roof?
*October 4, 2012*

**chemistry**

ethanol is a common laboratory solvent and has a density of 0.789 g/ml what is the mass in grams of 139 mL of ethanol
*September 3, 2012*

**math**

is 6.31 equal to 0.631
*March 26, 2012*

**Physics**

A prism, made of glass of refractive index 1.50, has two plane faces at an angle 33 to each other. A ray of light enters the glass from one side perpendicular to that face and emerges through the other. Part A: As the ray enters the glass, what is its angle of incidence ? Give...
*March 17, 2012*

**Physics**

Laser light with a wavelength = 665 illuminates a pair of slits at normal incidence. What slit separation will produce first-order maxima (i.e. m=1) at angles of 8 from the incident (or straight through) direction? Remember, 1 nm = m. Express your answer using two significant ...
*March 17, 2012*

**Physics**

A submerged scuba diver looks up towards the calm water of a lake and notes that the Sun appears to be 20 from the vertical. The diver's friend, standing on the shore of the lake, is also looking at the Sun. At what angle from the vertical does the diver's friend see ...
*March 17, 2012*

**Physics**

I don't know how to calculate it, that's why I was looking for help
*March 17, 2012*

**Physics**

A large fish tank is filled with water (of refractive index 1.33). One side of the tank is made of a parallel-sided piece of glass. A ray of light strikes the glass from the outside at an angle of incidence of 48. Estimate the angle through which this ray is deviated as it ...
*March 17, 2012*

**math**

how to solve the set of system equations 6x - y - 2 = 0 dan 3x - 2y + 5 = 0
*March 4, 2012*

**math- algebra**

If the principal P = $900, the rate r = 4 1/2, and time t = 1 year, find the following: What is the amount of interest? What is the future value?
*July 31, 2011*

**business**

2. Think of a risk response plan that you have in your personal life, such as automobile, homeowner’s, or renter’s insurance. What were some of the decision criteria that influenced your decision about how much coverage to purchase? How does your decision-making ...
*July 1, 2011*

**business**

1. What kind of risk analysis would you use when purchasing a house or a personal vehicle? Describe this analysis. How does this process assist you in making your decision? Do you believe the process is efficient and achieves the results you desire? How might you improve your ...
*July 1, 2011*

**Finding gradient at a given point**

44x + 11 :)
*February 27, 2011*

**Math**

6.34 x 10 to the fifth power
*December 2, 2010*

**Physics**

5000 / (72*144) pounds /inch^2 does this help baz my friend?
*November 6, 2010*

**Physics**

How much pressure is exerted by a 5000 pound moving vehicle vehicle (hehicle is 6' x 12')?
*November 6, 2010*

**spanish**

How would I complete this question? hago mi tarea en la_______
*August 31, 2010*

**1st grade**

if yo have three words friend, things & might which word has the long i sound and which word can you get by adding a sound to in? a tin,b hid c find
*March 29, 2010*

**Grammar**

Which sounds better my brother knows more about technology than me or I
*March 19, 2010*

**math**

for people each bought two bottles of vermont maple syrup. each person plans to share their bottle with three friends. how much does each person get?
*February 18, 2010*

**grammar**

The dock is on Fish Lane. CAPITALIZE the proper nouns in the sentence.
*December 8, 2009*

**grammar**

trying to Capitalize the proper nouns in the sentence
*December 8, 2009*

**garmma**

She and mom got to the Dock late.
*December 8, 2009*

**physic**

WAIT!!!!! i did h-r instead of h+r... therefore rework the steps with h+re instead of h-re..... sorry
*December 4, 2009*

**physic**

which it's not at all... if you start with g=GMe/re^2 then the difference in the two gravitys would be: (GMe/re^2)-(GMe/(h-re)^2=.007 to get like sides here, start by factoring out a GME... leaving you with GMe(1/re^2 - 1/(h-re)^2)=.007 divide both sides by GMe and you ...
*December 4, 2009*

**physic**

Actually, to do it the way he did would be wrong all together, because you would have to foil the (1+h/re)^2... you would have to multiply bothe sides by (1+h/re)^2 first... giving you: GMe-GMe=.007(1+h/re)^2 Obviously, GMe-GMe would give you zero... creating a quadractic ...
*December 4, 2009*

**literature**

"The best in this kind are but shadows" is
*December 1, 2009*

**Physics121**

What are the three longest wavelengths for standing sound waves in a 124-cm-long tube that is (a) open at both ends and (b) open at one end, closed at the other?
*November 7, 2009*

**1st grade**

She and mon got to the Dock late.
*June 16, 2009*

**Accounting**

Horse Country Living publishes a monthly magazine for which a 12-month subscription costs $30. All subscriptions require payment of the full $30 in advance. On August 1, 2008, the balance in the Subscriptions Received in Advance account was $40,500. During the month of August...
*March 31, 2009*

**Writing**

How can we answer this question in that section 1 and2
*March 21, 2009*

**human life**

WHOSE LIFE IS IMPORTANT?
*January 17, 2009*

**Business English**

Sorry if I spelled your name wrong. If you do not care it would be some good news joceyln
*November 21, 2008*

**Business English**

Wow. You have a lot of posts for your question Jocelyn
*November 21, 2008*

**Business English**

Hi hi hi hi
*November 21, 2008*

**Business English**

If I am annoying then tell me to stop. To tell me to stop you have to search my name in the right box that says search. P.s. it's right above the member login. Then click my name and annoy me to tell me to stop!
*November 21, 2008*

**Business English**

If I am annoying then tell me to stop. To tell me to stop you have to search my name in the right box that says search. P.s. it's right above the member login. Then click my name and annoy me to tell me to stop!
*November 21, 2008*

**Business English**

Bye Bye Bye Bye
*November 21, 2008*

**Business English**

Hi Hi Hi Hi
*November 21, 2008*

**Finance**

I dont have a formula for this question: Purchasing Power= 1280.08 (Nov.1/07) Purchasing Power= 1000.00 (Nov.1/97) What is the annual rate of inflation? I think it can be solved 1280.08/1000 -1 but Im not sure??
*November 7, 2008*

**English**

What is the rhyme scheme, meter, and stanza form for the poem "The Lamb" by William Blake? The Lamb Little Lamb, who made thee? Dost thou know who made thee? Gave thee life, and bid thee feed By the stream and o'er the mead; Gave thee clothing of delight, Softest...
*September 14, 2008*

**Physics / Astronomy**

Here is my question: Consider the bending of light by the gravitation of the Sun as described by Newtonian physics. Light of frequency f passes at a distance d from the center of the Sun, which has a mass M. Show that the bending angle of the light is proportional to M/d. I&#...
*May 28, 2008*

**Statistics**

a) .0225 b) =1-P(x=0)=.0445 c) I do not know.
*October 3, 2007*

**english**

what are the pros and cons of joining "netville 2" a computer company that came to your neighbourhood. We will be happy to critique your thinking on this. thanks im having trouble thinking of cons. The only thing i have for cons are: hidden fees and isolation and i ...
*April 21, 2007*

**physics**

A bat flying in a cave emits a sound and receives its echo 0.5 s later. How far away is the cave wall? I answered this below. If you cant find it, search on bat flying in the search window above.
*November 5, 2006*

**physics**

A skipper on a boat notices wave crests passing his anchor chain every 9 s. He estimates the distance between wave crests to be 15 m. He also correctly estimates the speed of the waves. What is this speed? Wavelenght* frequency= wave speed remember that frequency here is 1wave...
*November 5, 2006*

**physics**

A car crashes into a wall at 20 m/s and is brought to rest in 0.1 s. Calculate the average force exerted on a 75 kg test dummy by the seat belt. Force*time= change in momentum mv solve for force.
*September 27, 2006*

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