Questions Asked on
May 30, 2011

Chemistry
IF 80mg of a radioactive element decays to 10mg in 30 minutes, the halflife of this element is a.10 min b.20 min c.30 min d.40 min the answer is a.10 min but i would like to know why, please help.
asked by Jazmin 
physics
a car, moving at 100 mi/hr, passes a stationary police car whose siren has a frequency of 500 Hz. what is the frequency change heard by observer in the moving car as he passes the police car? the velocity of sound in air is 343 m/s. ( 1 mi= 1.609 km).
asked by OMAR 
Math
A box has a volume of 7500 cm3 and a surface area of 2600 cm2. What are length, width, and height of the box?
asked by Sweet girl 
Chemistry
Phosphoric acid reacts with magnesium hydroxide to produce magnesium phosphate and water via the following reaction:H3PO4 + Mg(OH)2 > Mg3(PO4)2 + H2O.Balance the equation, then enter the coefficients
asked by Christy 
Life orientation
Discuss ways in which xenophobia impacts on the community
asked by Happiness 
chemistry
water and ammonia have different molar heats of vaporization. the best interpretation at the molecular level is that water molecules
asked by joan 
maths
if sinA+cosA=1/5, then a value of tanA/2 satisfies which of the equation? a. 2x^2x1 b.x^22x3=0 c.2x^25x3=0 d. 2x^37x^2+2x+3=0
asked by shreya 
trig
If cos(t)=(7/8) where pi
asked by Char 
chemistry
Given the following data at 298K, calculate delta S for : 2Ag2O(s) > 4Ag(s) +O2(g) deltaS(J/mol.K)121.3 42.6 205.2
asked by Amy 
Sciene
A Compound has 40 g of calcium and 160 g of bromine. What is the mass ratio of calcium to bromine in the compound?
asked by Shakema 
Chemistry
Calculate the molar entropy of vaporization for liquid hydrogen iodide at its boiling point 34.55 degrees celcius. HI(l) HI(g) deltaHvap = 19.76 kJ/mol
asked by Amy 
physics
A softball of mass 0.220 kg that is moving with a speed of 4.0 m/s (in the positive direction) collides headon and elastically with another ball initially at rest. Afterward the incoming softball bounces backward with a speed of 1.8 m/s. a) Calculate the
asked by Nick 
statistics
10.15 A psychologist theorized that people can hear better when the have just eaten a large meal. Six individuals were randomly assigned to eat either a large meal or a small meal. After eating the meal, their hearing was tested. The hearing ability scores
asked by joe 
Chemistry 1
You carefully weigh out 17.00g of CaCo3 powder and add it to 68.85g of HCl solution. You notice bubbles as a reaction takes place. You then weigh the resulting solution and find that it has a mass of 78.88g . The relevant equation is CaCo3(s)+ 2HCl(aq)>
asked by Christy 
trig
how much force is necessary to stop a 2500 pound car from rolling down a 40degree slope
asked by Anonymous 
Physics
An object is placed 30mm in front of a lens. An image of the object is located 90mm behind the lens. a) Is the lens converging or diverging? explain. b) What is the focal length of the lens? c) Draw a diagram with lens at x=0, locate the image. d) Is the
asked by Harly 
chemistry
A sample of argon gas occupies a volume of 295ml at 36 C. What volume will the gas occupy at 55 assuming constant pressure?
asked by Anonymous 
math
You are given the probability of event E. Find the odds in favor of event E and the odds against event E. a. 1/8 b. 2/5
asked by Nicholas 
algebra
Yolanda's yogurt house offers 3 different kinds of yogurt and 13 different kinds of toppings. How many different yogurt and topping combinations are possible?
asked by Sabrina 
economics
4. What source of economic growth is reflected in the economy by an increase in productivity without an increase in land, labor, or capital? A. technological progress B. foreign trade C. population growth D. savings and investments
asked by Codey 
Trigonometry
verify the identity: 1 (cos^2x)/(1sinx)= sinx
asked by Sean 
chemistry
Given the following data at 298K, calculate delta S for : 2Ag2O(s) > 4Ag(s) +O2(g) deltaS(J/mol.K)121.3 42.6 205.2
asked by Amy 
Empirical Probability
Explain how empirical probability can be used to determine whether a die is “loaded” (not a fair die).
asked by Melanie 
Math
In a geometric series, t1=12 and S3=372. What is the greatest possible value for t5? Justify your answer.
asked by Carol 
Form a polynomial f(x) from coefficient and it's 0
Form a polynomial, f(x), with real coefficients having the given degree and zeros. Degree: 4; zeros: 6i and 7i I completely don't know what to do with this problem... if someone can solve and give a good explanation, I'd appreciate it. Thanks.
asked by Armando 
pre algebra
The perimeter of a triangle is 24 cm. One side is 2 cm longer than the shortest side. The longest side is 2 cm less than twice the length of the shortest side. Find the length of each side of the triangle. write equation and solve.
asked by Sammi 
physics
a cyclist travels a distance of 4km from p to q and moves a distance of 3km at right angle to pq .find his resulted displacement graphically
asked by gunjan 
physics
suppose a particular atom has only two allowable electron orbits. how many different wavelength photons (spectral lines) would result from all electron transitions in this atom? 1. three 2. four 3. None of these 4. one 5. two please help..
asked by rista 
algebra
How many ways can the offices of president, vicepresident, treasurer, secretary, parliamentarian, and representative be filled from a class of 30 students?
asked by Sabrina 
math
Lighting hit a tree threeeighths of the distance up the trunk from the ground and broke the tree so that its top landed 40 feet from the base of the trunk. How tall was the originally tree?
asked by Katherine 
math
37. A person deposited $500 in a savings account that pays 5% annual interest that is compounded yearly. At the end of 10 years, how much money will be in the savings account?
asked by Anonymous 
algebra
how to write 6000 in scientific notation without exponents
asked by A B 
Trigonometry
Verify the Identity: (1cosx)(1+cosx)=sin^2x
asked by Sean 
spanish
What does " Que estudias tu" mean in spanish?
asked by Chase 
physics
a 1500 kg car travelling at 16.7 m/s to the south collides with a 6300 kg truck that is initially at rest at a stop light. the car and the truck sticks togetherand moves together after the collision. what is the final velocity of the twovehicle mass?
asked by OMAR 
accounting..please help
can you help me please for this solving problem below... problem: A, B and C shared the profit of Rs. 9,00,000 in the ratio of 2:2:1 without providing for interest on B’s loan, B granted a loan of Rs. 4,00,000 in the beginning of accounting year. Where
asked by jessie 
life orientation
name two institutions in south africa that are involved in supporting or giving redress to these water pollution disasters.explain how these organizations are involved in providing a safe and healthy environment.
asked by noko 
Math
What is the solution to the system? x+y+z=8 xyz=6 2x3y+2z=1
asked by Kay 
ALGEBRA2
What is the value of k in the equation 6X^2 plus KX10 equals (3X plus 2)(2X5)
asked by ALE 
Trigonometry
(1+ tan^2x)/(secx)
asked by Abigail 
Algebra 2
1. A rectangle has an area of x3 + x2 – 7x + 2 square meters and a width of x – 2 meters. Find its length.
asked by Sheryl 
history
During and after the Revolution, why did the emancipation of slaves proceed very slowly in the northern states?
asked by Anonymous 
Statistics
if 25% of all students asked say they spend too much time on homework, and 12 students are selected at random, what is the expected number of students who say they spend too much time on homework?
asked by Mo 
physics
a sound wave has frequency of 631 Hz in air and a wavelength of 0.54m. what is the temperature of the air? assuming the velocity of sound at 0 degree celcius is 334 m/s. answer in units of celcius.
asked by OMAR 
physics
Two forces,F1 and F2, act at a point. F1 has a magnitude of 8.00 N and is directed at an angle of 56.0 degrees above the negative x axis in the second quadrant. F2 has a magnitude of 5.00 N and is directed at an angle of 52.9 degrees below the negative x
asked by physics please describe process 
Trigonometry
sin x= 1
asked by Abigail 
Math
Solving systems of equations with three variables? What is the solution to the system? 1] x+y+z=3 2] 3yz=4 3] 2xy2z=5
asked by Kori 
Algebra II
What is the solution to the system? 2x+y=9 x2z=3 2y+3z=15
asked by Kori 
Dividing Polynomials
I do NOT get this, please help: (11x^2+2x^3+14+17x)/(2x+5)
asked by Sheryl 
Math
A design on a balloon is 2 cm wide when the balloon holds 47 cm^3. How much must the balloon hold for the design to be 6 cm wide? I'm confused about how to solve this. Could someone please show me the steps?
asked by Annie 
physics
A reciprocating compressor is a device that compresses air by a backandforth straightline motion, like a piston in a cylinder. Consider a reciprocating compressor running at 150 rpm. During a compression stroke, 1.30 mol of air is compressed. The
asked by Joseph 
english
find adverb in "This is one of the most democratic way to buy art. Online galleries can exhibit the work of hundred of artists specializing in many different genres including figurative, abstract, landscape , still life, sculpture and so on. This gives you
asked by kara 
to Damon
Sorry had to adress this to you as you're the only tutor online right now, and I really need help. My teacher looked at my answers. And she said she still wants me to add more information, so Im having some troubles. Here is a Louis Riel Summation to the
asked by Emma 
trig
prove as an identity 1/1+sin(x) + 1/1sin(x)
asked by mel 
math
35. A person hired a firm to build a CB radio tower. The firm charges $100 for labor for the first 10 feet. After that, the cost of the labor for each succeeding 10 feet is $25 more than the preceding 10 feet. That is, the next 10 feet will cost $125, the
asked by Anonymous 
english
what does this mean: His [Claudius'] primary role in the play is to spawn Hamlet's confusion and anger, and his subsequent search for truth and life's meaning. What do they mean by spawn? isnt dat fish eggs?
asked by Viola 
substance
How alcoholism is a human factor that may cause ill health ,accidents,crises or disasters
asked by Anonymous 
English
Can you please check these two sentences, please? Thank you 1) Nature ceased to be considered as a philosophical entity (concept?). It came to be felt as a real living being (real and living being) and to be described as it actually was. 2) The Romantics
asked by Henry1 
fin534
In order to expand its business, Auto Parts Distributing, Inc., is considering the purchase of four pickup trucks at a total cost of $180,000. The company expects to keep these trucks for four years, then sell them. The company expects these trucks to
asked by jan 
Trigonometry
solve: tan x/2= sqrt3/ 3
asked by Randolph 
math
true or false? the function f1 (x)x/9 is the inverse function of f(x)=9x
asked by Altagracia 
Physics
Acceleration due to gravity is 9.81 m/s/s. What is the weight (in Newtons) of a 97.96 kg mass?
asked by Ed 
Psychology
There are five major perspectives of psychology used to explain a human behavior and mental processes. These five perspectives that I am referring to are Neuroscience, Psychodynamic, Behavioral, Cognitive and Humanistic The instruction that I have in my
asked by Sharon 
Trigonometry
verify the identity: 1cos^2x/1sinx= sinx
asked by Peter 
physics
A rectangular loop with sides l and w are inside of a region with constant magnetic field B is pulled to exit the region with velocity v. a) find the magnitude of the net induced emf on the loop b) find the direction of the current induced on the loop
asked by MichaelangeloZ 
Math
what is PSU's (penn state university)"annual scholarship" i have to fill out the yearly tuition & the room and board amount which all equals to $36,144. I need the annual scholarship amount but idk where to find that information...
asked by surfsupmel 
maths
Help please. Solve the following equation. 9x+1=13+7x
asked by susan 
Algebra 2
the demand for a new video game is given by the function p(x)= x^2 + 5x +75. Correspondingly, the supply function for the same game is given by p(x) = 7x9, where p represents the price per video in dollars and x represents the number of video games sold
asked by someone 
Trigonometry
If tan theta= 3 and Pi
asked by Adam 
Trigonometry
2cos[xpi/8]sqrt2=0 Pi=3.141592654
asked by Adam 
find real and complex 0
Find the real and complex zeros of the following function. Please show all of your work. f(x) = x^3 + 2x^2  6x + 8
asked by Armando 
Trigonometry
2cos^2theta3costheta+1=0 inerval [0,2Pi)
asked by Adam 
us history
doing a final review crossword and i cant figure these two out 1. Planned_____; creating products that would wear out over a given period of time ( _ _ _ _ _ _ n _ _ _ _ _ _) 13 letters 2. a clear indication of nationwide voter support ( _ a _ _ _ _ e) 7
asked by logan 
science
if removed from the life cycle, which of the following would have the greatest impact on the productivity of lawns. 1. robins 2. moles 3. toadstools 4. dandelions 5. microrganisms i think 4 b/c of the seedd that are easily blown away in the wind to
asked by John 
Science
0.05 M KOH?
asked by Ah 
EnglishNovel
I am looking for a novel that's set in the 19801999 in Zimbabwe. Any recommendation is appreciated.
asked by May 
Math
Hi Ihave the solution and all thE steps for this question.:.but I am still having a hard time understanding it :( could somebody please help me walk through all the steps to this question? 1) assume that an average television costs $425 now and that the
asked by Dawn 
Pre Algebra
Four numbers are drawn from random tiles numbereed 0 through 9. What are the odds of drawing numbers 1 through four in any order?
asked by Katelyn 
Chemistry
which of the following 10 g samples will decay the most in 28 days? a.P32 b.Kr85 c.Fr220 I131 the answer is c.Fr220 but i want to know why, please help
asked by Jazmin 
maths
what will come in blank y*y*y*_____________p times=________
asked by aekansh 
chemistry
What are the steps to determine how much Nitrogen Gas can be produced from 32.5 grams of Sodium Nitrate?
asked by Dax 
Math
A square and four congruent rectangles are arranged in a larger square. The smaller square and each of the rectangles have the same perimeter.Determine the ratio of the length of a side of the larger square to the length of side of the smaller square.
asked by Eric 
Algebra 2
Add. Write your answer in standard form.(4e^5e^2)+(e^5+6e^21)
asked by A.Albert 
Geometry
one of the ancient store pyramids in egypt has a square base that measures 145m on each side. the height is 108m. What is the volume of the pyramid?
asked by Anonymous 
math
Can one cake be split into portions of 1/3; 3/9; and 8/15 or why not?
asked by sam 
math
Can one cake be split into portions of 1/3; 3/9; and 8/15? why or why not?
asked by sam 
management
what is the four elements of financial management.
asked by sam 
Trigonometry
verify the identity: (1cosx)(1+cosx)= sin^2 x
asked by Randolph 
precalculus
find the derivative of y=(3x+1)^2 y= square root 13x^25x+8
asked by gmp 
physics
A net force of 265 N will accelerate how much mass at 0.5 m/s/s?
asked by Ed 
Algebra 2
Whar number must be added to both sides of the equation to solve it by completeing the square? 3x^2+15x=9 (1)225 (2)25 (3)6.25 (4)5
asked by Callie 
english
The report was thorough.It saved the department several hundred dollars
asked by Anonymous 
Algebra
Find an equation of the line L that passes though the point (2,4) and satisfies the condition. L passes through the point (3, 7/2)
asked by Robo 
physics
what would be the distance from the image to the mirror if the imge form the object to the mirror is 20cm and the focal length is 10 cm
asked by Kelli Kenyon 
Math
Express as a single term in simplest form: 5/2 radical 12
asked by Rob 
Trigonometry
Use Heron's formula: a=46 b= 52 c= 67
asked by Peter 
Trigonometry
Solve: 2 cos[xð/8]sqrt2=0
asked by Sammy 
Trigonometry
Solve: 2cos^2 theta  3cos theta+ 1= 0 interval [0, 2ð)
asked by Abigail 
Trigonometry
Solve triangle ABC: B= 60 degrees, C= 90 degrees a= 4 feet
asked by Adam 
English
Could you please check these sentences, please? I'm not sure about the rephrase. 1)In the first stanza the poet remembers wondering aimlessly and alone in the countryside. All at once he was amazed by the sight of a crowd of daffodils dancing ad fluttering
asked by Henry1 
physics
What work is done when 6.0 C is moved through an electric potential difference of 1.5 V?
asked by Anonymous 
maths
i have fopur questions like this but don't undersand them. thanks Rearrange the formula a=(7/b+1)4 to make b the subject
asked by Beth 
English
Is it a mistake to write "Nature ceased to be consideres "as" a real living being?" I included a few more sentences. Thank you. 1) In the fourth stanza the poet suggests that in order to hear the voice of nature we should be in a state of inner emptiness
asked by Henry1 
MAT/116
I was just wandering if this was correct? 1. Your company is planning to spend no less than $80,000 and no more than $100,000 on a landscaping project, which will be used as a promotional park that promotes your toaster manufacturing company. Write an
asked by Vic 
maths
(400t300)(400t300)+(200t100)(200t100) complete the square showing all steps
asked by simon 
Legal
What are some possible defences for the tort of negligence? Australian.
asked by Em 
trig
Ok, so im brand new at trigonometry. If i have a right triangle with an acute angle of 30° an opposite side of 4 and a hypotenuse of x how do ii find x
asked by maya 
Science
PRessure is measured in Pascals (Pa). What combination of units is the same as a Pascal? and When you exert a force on a fluid in a closed container, does the pressure increase, decrease or remain constant? I think it will increase, but I'm not totally
asked by Erika 
math
multiply then simplify by factoring. if possible √2 √6 =
asked by nichole 
solving systems of equations with 3 variables
What is the solution to the system? x2y=1 x3y+z=0 2x2z=18
asked by Kori 
life orientation
how cancer impact on the teenagers
asked by noko 
Mathematics
Hi, I don't like asking for help .. can someone check my work please ? In a biometric system under testing there are 500 users. 200 were legitimate users (authorised), and 300 were not ( unauthorised) At one threshold the system: Shut out 10 individual
asked by Fred 
science
a person has a hert attack and her condition is stablised but due to inflamatiom in the lung she could not breath so a machine helps her to breath and now the lung inflamation is healing .Will she be able to breath on her own once the machine is cut off?
asked by xavier 
Math
The capital letter F can be formed by connecting the points (0,4)(5,4) (5,2)(2,2) (2,0) (4,0) (4,2) (2,2) (2,7) nad (0,7), in this order. Determine the slope of a line that passes through the origin and divides the letter F into two regions of equal
asked by Theo 
com
Can you please identify the adverbs and adjectives in the following paragraph. Having credit cards could get some people into serious debt. I had a credit card at one time. I learned the hard way about using credit cards. I was using it for anything and
asked by Tina 
Spanish
15. _____ le duelen mucho las piernas. a. Ernesto b. A los muchachos c. A Pablo d. El joven D?
asked by mysterychicken 
Trigonometry
verify the identity: (sin^3xcos^3x)/(sinxcosx)=1+sinxcosx
asked by Randolph 
Math
I don't know how to do this math 7n + 2 = 4n + 17
asked by Anonymous 
English
I forgot to include the following sentences. When I describe Wordsworth' conception of poetry, shall I use the present or the past? 1) Wordsworth believed poetry should deal with everyday situations or incidents and with ordinary people living in the
asked by Henry1 
Englishlord of the flies
Give five present day examples of similar characteristics or situations present in the novel lord of the flies.
asked by Kendra 
Life Orientation
Institutions/community organizations that are involved in supporting or giving redress to substance abuse.
asked by Sekgala LD 
Algebra
Simplify. 2/3(4x/2x^21)+3(3/3x1)
asked by Robo 
whole number
When stacking bags of dog food, the heaviest items should be placed at the bottom. Starting at the bottom, in what order should bags of dog food weighing 25 pounds, 20 pounds, 30 pounds, and 28 pounds be stacked?
asked by carol 
math
the area of a circle inscribed in the triangle formed by the line with equation x+y=1 and the two coordinate axes can be written in the form pi(a+b(sqr.c)/d) compute the value of a+b+c+d
asked by Theo 
Trigonometry
If tan theta= 3 and ð
asked by Sammy 
Trigonometry
Solve triangle SSA: A= 78 degrees, a= 30 b= 61
asked by Adam 
maths
how can i slove 5x2(x5)=15
asked by elizabeth 
US History
What does historical context mean?
asked by Anonymous 
psychology
1) What were some of the irrational beliefs and attitudes that the characters displayed?
asked by fay 
Trigonometry
Solve SSA: B=12.1 degrees b= 15 a= 23.9
asked by Sean 
Trigonometry
Solve SSA: A= 78 degrees a= 30 b= 61
asked by Sean 
Research
hi Are there any good image searches or databases? Preferably databases. IE, not google please. Thankyou
asked by Em 
Life oriantation
Human problem impacts on the community.
asked by Khumbulani 
math
use the distributive property to multiply then if possible simplify the resulting expression √3 (√3 √21)
asked by nichole 
Math
Find m
asked by ashley 
adding rational expressions
2/3x+4 + 6/x+2
asked by Sheryl 
adding rational expressions
2/5x + 1/9
asked by Jesse 
adding rational expressions
8 + x4/x+3
asked by Jesse 
math
perform the indicated operation 4√45 6√125=
asked by nichole 
math
the launch window for a weather satellite is represented by the inequality t360 < 20 where t minutes is the time from the start of the countdown to the launch. If the countdown starts at 01:00, at what times can the satellite be launched?
asked by hh. 
4 grade math
how do you write the number 12,346,823 in expanded form
asked by valeria 
heart
were is the heart found in the human body
asked by Anonymous 
math
if i had a 66 in bim and my teacher puts a 100 in the grade book what will be mi grade
asked by shabria cross 
space
A water tower has to be equidistant from three communities. The communities are at positions (25, 20), (5, 40) and (15, 30). Find the coordinates of the point where the water tower should be built.
asked by Anonymous 
Math
A pyramid is inscribed in a cube whose volume is 52pi cm^3. The volume of a sphere is equal tpo the volume of this pyramid. Find the volume of a second cube whose edge is equal to the radius of the sphere.
asked by Eli 
spanish
What does " Que estudias tu" mean in spanish?
asked by Chase 
financial management
what are the four elements of financial management and how can i summerize them?
asked by brianaae 
calculus
I need help with this calculus problem. H(S)=S/(1+S) If F 1/2, 1/2 & (a+1)? I can't figure out what this mean /?
asked by Tammy 
psychology
What are some of the basic steps in developing a training program in an organization? In training, what are needs assessments and how are they used?
asked by Holly 
Calculus
Evaluate the definite integral from [0,4] 4x^2 dx, by using its definition as a limit of approximating sums. First, I solve analytically so I know the answer I am trying to reach: 4/3 * x^3 over [0,4] = 4/3 * 4^3 = 256/3 Now, by approximating sums, I can
asked by Sean 
where do you place the comas
The oil from Eucalyptus trees which are native to Australia is known for its medicinal properties
asked by Anonymous 
physics
With a focal length of 10 cm, and D zero is 20, 15, 25, and 5, what is the D one
asked by Kelli Kenyon 
check
How do I right a check for 1,400 dollars?
asked by SARah 
algebra
Anthony's family plants 15 trees each weekend. If t is the total number of trees planted and w is the number of weeks, what is the expression for the total number of trees, t, planted after w weeks.
asked by Fred 
Math
A cylindrical tank with radius 6 in. and length 12 in. is placed on its lateral face with bases perpendicular to the ground and then filled with water to a height of 9 in. When the cylinder is rotated to sit on one of its bases, the height of the water
asked by Alex 
math
I can't figure this out this problem.. estimate 20% of 131 by using 10%
asked by sierra 
Reducing fractions
how do i reduce 8/28
asked by Frankie 
Life orientation
Derasice the style disease / behaviour and explain 5 (or more ) factors that contribute to the disease
asked by Lucky selamolela 
world history
In what year did citystates become common in greece
asked by maria 
trig
y = sin (3x2pi)
asked by mike 
Science
What are five ways that humans make an impact on the climate?
asked by Jarzo 
math
What do they mean when they say given angle and given side of a triangle???? I don't get this
asked by Traveling Girl 
science
can energy be lost or does it transfer somewhere else? I thought energy can be lost but i'm just checking.
asked by Anonymous 
geometry
one of the ancient stone pyraminds in egypt has a square base that measure 145m on each side. The hight is 108m. What is the volume of the pyramid?
asked by Anonymous 
Trigonometry
Solve SSA: B= 12.1 degrees b= 16 a= 23.9
asked by Peter 
Trigonometry
Solvetriangle ABC: a= 12.2 c= 7.8 B= 63.5 degrees
asked by Adam 
eng
I want to konw how harry potter support violence. I REALLY MEANT THIS ANSWER.
asked by ami