Saturday

May 28, 2016
Total # Posts: 1,159

**Physics**

A transverse wave traveling in a string takes 1.40 s to move 13.2 m. The mass of a 8.50 m piece of the string is 1.60 kg. What is the tension in the string?
*May 25, 2016*

**Physics**

The string is 0.95 m long with tension 8.00 N. The total mass of the string is 12.34 g. Find the period of the oscillation.
*May 25, 2016*

**my son's math help please**

Aaron baked two identical cakes.He cut one into 9 equal slices and the other into 18 equal slices.Which is greater 2/3 of the 9 slice cake or 1/3 of the 18 slice cake?
*May 24, 2016*

**Physics**

The difference in temperature between summer and winter causes the length of a pendulum in a clock to change by one part in 27000. If the period of the pendulum is 1 s, what time-difference error will this make in one hour?
*May 19, 2016*

**Help my son's math**

Tyvm sue
*May 18, 2016*

**Help my son's math**

You are given a choice of having 3/4 of an hour of free time 2/3 of an hour of free time on Friday afternoon.Which option would you choose.
*May 18, 2016*

**algebra 2b**

A simple random sample of 50 adults was surveyed, and it was found that the mean amount of time that they spend surfing the Internet per day is 54.2 minutes, with a standard deviation of 14.0 minutes. What is the 99% confidence interval (z-score = 2.58) for the number of ...
*May 17, 2016*

**help my son's math**

Dan baked enough peach pies for each of his 20 friends to have 1/8 of a pie. How many pies did he bake.
*May 9, 2016*

**Help my son's math**

Thank u very much
*May 4, 2016*

**Help my son's math**

A TRAIN IS TRAVELING AT A RATE OF 76KM EACH HOUR . ESTIMATED THE TIME IT WILL TAKE THE TRAIN TO TRAVEL 399KM??
*May 4, 2016*

**Physics Please Help!**

A small metal ball with a mass of m = 78.9 g is attached to a string of length l = 1.76 m. It is held at an angle of = 44.5° with respect to the vertical. The ball is then released. When the rope is vertical, the ball collides head-on and perfectly elastically with an ...
*May 3, 2016*

**Physics**

Two children are playing a game in which they try to hit a small box on the floor with a marble fired from a spring-loaded gun that is mounted on a table. (Image included with problem) The target box is 2.44 m horizontally from the edge of the table. Bobby compresses the ...
*May 3, 2016*

**Physics**

Consider an archery bow as behaving like a spring with a spring constant of 493 N/m. If an archer pulls the bowstring back for a distance of 42 cm, what is the elastic potential energy of the "loaded" bow? If the mass of the arrow is 39 grams, what is its speed as it...
*May 3, 2016*

**Physics**

Consider an archery bow as behaving like a spring with a spring constant of 493 N/m. If an archer pulls the bowstring back for a distance of 42 cm, what is the elastic potential energy of the "loaded" bow? If the mass of the arrow is 39 grams, what is its speed as it...
*May 3, 2016*

**Physics**

By how much will a 1.52 kg object stretch a spring that is suspended vertically if the spring constant is 135 N/m? The object is pulled straight down by an additional distance of 25.4 cm and released from rest. Find the speed with which the object passes through its original ...
*May 3, 2016*

**Physics**

Use the following information to calculate the speed of a ball in a pinball machine at a specific location. The ball is launched by using a spring (k = 700 N/m) compressed by 8.5 cm. Consider the starting position of the ball to be its location when the spring is compressed. ...
*May 3, 2016*

**Physics**

A bullet (m = 0.0250 kg) is fired with a speed of 94.00 m/s and hits a block (M = 2.20 kg) supported by two light strings as shown, stopping quickly. Find the height to which the block rises. Find the angle (in degrees) through which the block rises, if the strings are 0.200 ...
*May 3, 2016*

**Physics**

A small metal ball with a mass of m = 78.9 g is attached to a string of length l = 1.76 m. It is held at an angle of = 44.5° with respect to the vertical. The ball is then released. When the rope is vertical, the ball collides head-on and perfectly elastically with an ...
*May 3, 2016*

**Physics**

The target box is 2.44 m horizontally from the edge of the table. Bobby compresses the spring 1.42 cm, but the center of the marble falls 84.0 cm short of the center of the box. How far should Rhoda compress the spring to score a direct hit?
*May 3, 2016*

**Physics**

A fighter jet is traveling at 200 m/s following the arc of a vertical circle of radius R. At the top of its path, the pilot experiences “weightlessness.” What is the value of R?
*May 2, 2016*

**Calculus**

Sketch the region enclosed by the curves given below. Decide whether to integrate with respect to x or y. Then find the area of the region. y=4cos(x),y=4−8x/π. I thought it was the integral of 4cos(x)- the integral of 4- 8x/π on the interval 0 to π/2. This...
*April 27, 2016*

**Chemistry**

Which of the following is a stronger lewis base: cyanide ion or dicarbide ion? I'm assuming it is the dicarbide ion as it is more negatively charged and a compound consisting of 2 carbons is larger and therefore more likely to lose electrons than something consisting of ...
*April 22, 2016*

**Physics**

In the Biomedical and Physical Sciences building at MSU there are 135 steps from the ground floor to the sixth floor. Each step is 16.0 cm tall. It takes 5 minutes and 40 seconds for a person with a mass of 63.9 kg to walk all the way up. How much work did the person do? What ...
*April 19, 2016*

**Physics**

In the Biomedical and Physical Sciences building at MSU there are 135 steps from the ground floor to the sixth floor. Each step is 16.0 cm tall. It takes 5 minutes and 40 seconds for a person with a mass of 63.9 kg to walk all the way up. How much work did the person do? What ...
*April 19, 2016*

**Chemistry**

What is the molar solubility of Mg(OH)2 in a solution containing 0,10 M NH3 ? Ksp Mg(OH)2 = 1.2x10^-11 Kp NH3 = 1.8x10^-5
*April 18, 2016*

**Chemistry**

What is the molar solubility of Mg(OH)2 in a solução containing 0,10 M NH3 ? Ksp Mg(OH)2 = 1.2x10^-11 Kp NH3 = 1.8x10^-5
*April 18, 2016*

**Physics**

A car is moving such that its kinetic energy is 6.20×105 J. The car accelerates and the engine does 2.90×105 J of work to accelerate the car. What is the final kinetic energy of the car? Ignore energy lost to friction. (Your answer must be accurate to at least 1%. ...
*April 15, 2016*

**Physics**

A man pulls a crate of mass 61.0 kg across a level floor. He pulls with a force of 186.0 N at an angle of 22.0° above the horizontal. When the crate is moving, the frictional force between the floor and the crate has a magnitude of 120.0 N. If the crate starts from rest, ...
*April 14, 2016*

**Physics**

A car (m = 610.0 kg) accelerates uniformly from rest up an inclined road which rises uniformly, to a height, h = 49.0 m. Find the average power the engine must deliver to reach a speed of 24.7 m/s at the top of the hill in 20.5 s(NEGLECT frictional losses: air and rolling, ...)
*April 14, 2016*

**Chemisty**

An ideal gas with an initial volume of 96L, temperature of 277K, and 7.3mol is permitted to come to a second state with a volume of 450mL and a temperature of 203C. Show the calculation for the final number of moles of gas in the system. (P1)(V1)/(n1)(T1)=(P2)(V2)/(n2)(T2) (P1...
*April 10, 2016*

**Math**

A 1963 Chevy Bel Air a classic car today, cost $2400 new in mid 1963. How much would that be in 2012 dollars?
*April 8, 2016*

**Physics**

Two golf carts are driving towards each other. The first has a mass of 390 kg and is driving east at 20 m/s. The second has a mass of 500 kg and is driving west at 8 m/s. When the two collide their bumpers lock and are stuck together, what is the final speed of the connected ...
*April 7, 2016*

**Physics**

A man is in a boat out away from shore. The mass of the man and the boat is 188 kg. The boat is not moving. The man throws and anchor with a mass of 22 kg straight out from the boat with a speed of 13.8 m/s. What is the resulting speed of the boat?
*April 7, 2016*

**Biology**

I'm doing a research paper on Plectaster decanus, the Mosaic Sea Star and I'm looking for certain information on its diet. There is little information on the internet about this species so I was wondering what is the general diet of a southern Australian sea star? Also...
*April 5, 2016*

**Chemistry**

Okay so this was my next step 0.765 mol CaCO3 x 1 mol CO2/2 mol HI = 0.3825mol CO2. At STP, 1 mol=22.4L so (22.4)(0.3825mol)= 8.568 L CO2 Does that look right?
*March 28, 2016*

**Chemistry**

Given the reaction 2HI (aq) + CaCO3(s) = CaI2(aq)+CO2(g)+H2O(l) What volume of of CO2 can be produced from 255mL of 3.0M HI and 75.2g of CaCO3 at STP? 75.2g CaCO3/100.09g/mol CaCO3 =.751mol CaCO3 (3M)(.255L)=.765 mol HI
*March 28, 2016*

**Chemistry**

Correction!! Cr2O7^2-(aq)+ 6F^-(aq)+14H+ = 2Cr^3+(aq)+3F2(aq)+7H2O(l) Is what I get, I put electrons on the wrong side for F to F2.
*March 15, 2016*

**Chemistry**

Well thank you very much for the site, it helps! I've worked out the problem myself, please tell me if this looks okay? Cr2O7{2-} +F-=Cr{3+}+F2 6e^- + Cr2O7^3- + 14H^+ = 2Cr^3+ + 7H2O 2F^- = F2 +4e^- Then I multiplied the top by 2 and the bottom by 3 to get a GCF for the ...
*March 15, 2016*

**Chemistry**

Use the method of half reactions to balance the oxidation half reaction in acid solution as well as provide the oxidized and reduced reactants. Cr2O7 {2-} (aq) + F{-} (aq) = Cr {3+} (aq) + F2(aq) Charges are in { }
*March 15, 2016*

**Physics**

Many people mistakenly believe that the astronauts that orbit the Earth are "above gravity". Calculate g for space-shuttle territory, 206 kilometers above the Earth's surface. Earth's mass is 6e24 kg, and its radius is 6.38e6 m (6380 km). Your answer is what ...
*March 9, 2016*

**Physics**

The mass of a certain neutron star is 3.4e+30 kg(around 1.5 solar masses) and its radius is 8400 m. What is the acceleration of gravity at the surface of this condensed, burned-out star? (Note on scientific notation: 3e+30 means 310^30.)
*March 9, 2016*

**Physics**

Find the change in the force of gravity between two planets when the distance between them is decreased by a factor of 4.7
*March 9, 2016*

**Chemistry**

Thanks Bob! Curious where .90 comes from? .0009molX1000mL? .5/6= .083M
*March 8, 2016*

**Chemistry**

Calculate the molarity of 3 drops (0.15mL) of a 0.5M Na3PO4 solution after adding 15 drops (.75mL) of water. (Presume drops are the same size, one drop = 0.05mL)((Presume volumes are additive)) So far I've figured .15g Na3PO4/163.94g/mol Na3PO4 = .0009moles .75g H20/18.015...
*March 8, 2016*

**AP Physics**

Two speakers, one directly behind the other, are each generating a 406-Hz sound wave. What is the smallest separation distance between the speakers that will produce destructive interference at a listener standing in front of them? Take the speed of sound to be 344 m/s.
*March 8, 2016*

**Biology**

I have a research article about the early advancement of laying times for Flycatchers, a bird species through Europe and Asia. My variables are: - Annual temperature recordings in each study site - The species, flycatcher - Clutch size of the flycatchers - The location of each...
*March 7, 2016*

**Finite**

Mike deposit $50 per week in account that pays 5% interest compounded weekly. how much will he have in the account at the end of 4years?
*March 7, 2016*

**Chemistry**

A solution is prepared by adding 45.0g of Na2SO4*6H2O to pure water to make 150mL of solution. What are molar concentrations of these ions in the resulting solution? Sodium Ion? Sulfate Ion? Phosphate Ion? I've determined the solution is 1.2M 45/250.16g/mol Na2SO4*6H2O = ....
*March 4, 2016*

**Math**

A rectangular park has an area of 6 square miles. The width of the property is 3/8 the length of the property. What is the width of the property? 6/1 x 3/8 = 18/8 = 2 and 2/8 = 2 and 1/4. 2 and 1/4 is my answer but in my test I got that wrong.
*March 3, 2016*

**physics**

A string under a tension of 43.0 N is used to whirl a rock in a horizontal circle of radius 2.25 m at a speed of 20.0 m/s on a frictionless surface as shown in the figure below. As the string is pulled in, the speed of the rock increases. When the string on the table is 1.00 m...
*March 2, 2016*

**Chemistry**

Show the calculation for the limiting reagent when 0.853g of sodium sulfate (95% pure) react with 1.707g of barium hydroxide octahydrate (87% pure) to produce a precipitate of barium sulfate. I've determined the equation is Na2SO4+Ba(OH)2*8H2O=BaSO4+2NaOH However, that is ...
*March 1, 2016*

**Chemistry**

what is the oxidation number of Chlorine in KCIO4???
*February 26, 2016*

**Physics**

A small object with a mass of m = 615 g is whirled at the end of a rope in a vertical circle with a radius of r = 123 cm. When it is at the location shown, (mid-height), its speed is v = 5.60 m/s. Determine the tension in the rope. Calculate the magnitude of the total force ...
*February 26, 2016*

**Physics**

A test tube in a centrifuge is pivoted so that it swings out horizontally as the machine builds up speed. If the bottom of the tube is 160.0 mm from the central spin axis, and if the machine hits 40500 rev/min, what would be the centripetal force exerted on a giant amoeba of ...
*February 26, 2016*

**Chemistry**

Consider the following reaction: CO2 (g) + H2 (g) CO (g) + H2O (g) Calculate the value of the equilibrium constant, Kc, for the above system, if 0.1908 moles of CO2, 0.0908 moles of H2, 0.0092 moles of CO, and 0.0092 moles of H2O vapour were present in a 2.00 L reaction vessel...
*February 25, 2016*

**Chemistry**

5. Consider the following reaction: CO2 (g) + H2 (g) CO (g) + H2O (g) Calculate the value of the equilibrium constant, Kc, for the above system, if 0.1908 moles of CO2, 0.0908 moles of H2, 0.0092 moles of CO, and 0.0092 moles of H2O vapour were present in a 2.00 L reaction ...
*February 25, 2016*

**Chemistry**

Calculate the pH of a NaOH solution of concentration 0.5M (Kw = 1.0 x 10-14 mol2dm-6 at 25oC)
*February 25, 2016*

**Chemistry**

2. Does a precipitate of silver chloride form when 200.0 mL of 1.0 x 10-4 M AgNO3 (aq) and 900.0 mL of 1.0 x 10-6 M KCl (aq) are mixed at 25oC?[ Ksp AgCl @ 25oC = 1.6 x 10-10]
*February 25, 2016*

**Math**

the sum of two numbers is 27. one number is 3 more than the other number. write and solve a system of equations to find the two numbers. i understand the first equation but i dont know the other one.
*February 18, 2016*

**Math**

Jackie makes patterns. She makes each pattern with 5 counters. she makes 13 patterns. How many counters does she need? Show your working.
*February 18, 2016*

**Cal 2**

Find the volume of the solid obtained by rotating the region bounded by the given curves about the specified axis. y=1/x^3,y=0,x=4,x=7. About the y-axis. Volume =
*February 12, 2016*

**Social Studies**

Why do we celebrate black history month?
*February 11, 2016*

**math**

Thanks!
*February 9, 2016*

**math **

Problem: Lexington, and Elizabethtown, Kentucky are 79 miles apart. If the distance on the map is 2 1/2 inches, find the scale of the map. do i make a ratio for inches to miles? is it 2.5x inches = 79 miles?
*February 9, 2016*

**pre-calclus **

State the amplitude, period, phase shift, and vertical shift of the function y= -3 (1/2x- 2/3 pi)-4
*February 7, 2016*

**Chemistry**

The molarity of concentrated HCl purchased for laboratory use is approximately 12.1 M. How many milliliters of this reagent should be diluted to 1.000 L to make 0.100 M HCl?
*January 19, 2016*

**dynamics**

(a) A rocket is travelling out of the earth’s atmosphere. During flight it burns fuel at a rate of 80kg/s producing a constant thrust of 500kN which drives the rocket in a vertical trajectory. It has a mass of 3500Kg when it reaches a speed of 1220m/s. At this point in ...
*December 29, 2015*

**Statistics**

ln a box of 200 computer chips 30 of them are defective. lf 3 chips are chosen at random with replacement, what is the probability that at least one of them is defective?
*December 15, 2015*

**chemistry**

the number of moles in 12.04x10^23 molecules of Oxygen
*December 12, 2015*

**Walk two moons**

What is the meaning of the fourth message in your own words?
*December 9, 2015*

**health**

What are the ten building blocks for total health
*December 8, 2015*

**chemistry**

Stoichiometrics: a 36 grams sample of calcium hydroxide is allowed to react with 40.5 grams of phosphoric acid according to the following reaction. 3Ca(OH)2 + 2H3PO4 = Ca3(PO4)2 + 6H2O how many grams of calcium phosphate are produced? how many moles of Calcium phosphate are ...
*December 5, 2015*

**chemistry**

a 36 grams sample of calcium hydroxide is allowed to react with 40.5 grams of phosphoric acid according to the following reaction. how many grams of calcium phosphate are produced? how many moles of calcium phosphate are produced? how many moles of excess reagent remain? if 43...
*December 5, 2015*

**chemistry**

a 36 grams sample of calcium hydroxide is allowed to react with 40.5 grams of phosphoric acid according to the following reaction.
*December 5, 2015*

**Chemistry **

Calculate the final temperature in degrees Fahrenheit of 1.25 liters of gas X at 85 degrees Celsius and 2700 mm/Hg, if the pressure is changed to 2.35 atmospheres and the volume is increased to 2500ml
*December 4, 2015*

**Chemistry**

if 16.5 liters of gas X is at 398 torr and -90.5 degrees celsius, what would be the volume of this same gas if the pressure is changed to 3.1 atmospheres and the temperature is changed to 399K
*December 4, 2015*

**Physics**

A stone is aimed at a cliff of height h with an initial speed of v = 36.0 m/s directed 75.0° above the horizontal, as shown in the Figure below by the arrow. The stone strikes at A, 6.25 s after launching. What is the height of the cliff?
*December 3, 2015*

**Chemistry**

50g*1mol/26.04g*2molh20/1molC2H2*18.02g/1molh20 69.20g H20 needed to make 50g c2h2
*December 1, 2015*

**physics**

So in projectile problems horizontal a=0 so the velocity is constant. So finding x and y components for initial velocity X: 172.5m/s*cos30=149.4m/s Y: 172.5m/s*sin30=86.25m/s The max height is at the apex of the projectile, so use vertical velocity in Vfy =Viy+at---> -vi/a=...
*December 1, 2015*

**physics**

A projectile is fired at 30.0° above the horizontal. Its initial speed is equal to 172.5 m/s. Assume that the free-fall acceleration is constant throughout and that the effects of the air can be ignored. What is the maximum height reached by the projectile? At what time ...
*December 1, 2015*

**Physics**

A person who is 1.1 m tall throws a ball with a speed of 5.2 m/s at an angle of 56 degrees above the horizontal. What are the x and y components of the velocity (in m/s) of the ball the instant before it strikes the ground? The acceleration due to gravity is 10 m/s2
*December 1, 2015*

**Physics**

The launching speed of a certain projectile is 6.8 times the speed it has at its maximum height. Calculate the elevation angle at launching.
*December 1, 2015*

**Physics**

A catapult on a cliff launches a large round rock towards a ship on the ocean below. The rock leaves the catapult from a height H = 32.0 m above sea level, directed at an angle theta = 46.9° above the horizontal, and with a speed v = 29.6 m/s. Assuming that air friction ...
*December 1, 2015*

**Science**

Well I'm not sure if you need it in MKS system or not but here is the conversion 66km/hr*1hr/60min*1min/60sec*1000m/1km =18.06m/s or .01806km/s Since the car is stopping its final velocity =0 Use the equation Vf=Vi+a*t (Where vf is final velocity vi is initial velocity a ...
*December 1, 2015*

**physics**

Hmm, I may be overlooking something here, unless the mass is irrelevant, but I drew Y0=0 V0=8.1m/s VF=0m/s( because the jumper reached Yf stops and comes back down toward earth) and a=9.8m/s^2 so you're looking for Y final position I used Vf^2=V0^2+2a(Yf-Y0) since vf=0 and...
*December 1, 2015*

**PHYSICS**

So this gives you the mass and force of m1, use Newton's second law (F=m*a) to get the acceleration.... 33.0/4.5kg=7.33 m/s^2 I drew this situation as [m1]----[m2] since the applied force was to the right the --- tension force becomes limp and should =0 [m1]>~~_[m2] it...
*December 1, 2015*

**math**

A: FUNCTION Q1. (a) The function C (x) = 25x + 80,000 express the total cost C (x) (in K£) of manufacturing x units of a product. If the maximum number of units which can be produced equals 20,000, state the restricted domain and range for this function. (b) An analysis ...
*December 1, 2015*

**math**

Well50k-27k=23k So since 8.5%interest is on Corp bonds 27000*.085=2,295 23,000*.068=1,564 3,859$ is the most he makes from interest Since it says maximum income look at the maximum amount he count spend on the higher interest rate then subtract from the total he wants to spend...
*December 1, 2015*

**Chemistry**

pH=Pka+log[A-]/[HA] Pka=-log 1.8x10-5 +log (.025/.053) Divide the concentrations out and take the log of it and add it to the negative log of 1.8x10-5 You can tell HC2H3O2 is the acid because Ka is the constant for the acid, while Kb would be constant for the base. I don't...
*December 1, 2015*

**biology**

Which of the following organelles is common to both prokaryotic and eukaryotic cells? Cytoskeleton Nucleus Nucleolus
*November 30, 2015*

**algebra**

A wire is 264 ft in length is to be cut into two pieces, one to form a rectangle whose length is four less than twice the width, and the other to form a square whose side is equal to the sum of the width and the length of the rectangle. how long is the shorter piece of wire
*November 29, 2015*

**c programming**

Write a program to read from a file called "input.txt" information about 5 workers. Each line would contain two values respectively, an employee ID and the employee's monthly salary. Assume that the data from the input file is stored in a format as shows in this ...
*November 26, 2015*

**Calculus**

Let f(x)=5x^(9/5)−45x^(4/5). Find the largest open interval(s) where f(x) increases.
*November 23, 2015*

**Math**

Let f(x) be a function such that f′(x)=x(ln|x|)^2. Find the open interval(s) in which f(x) is concave down . In interval notation, f(x) is concave down in ___________
*November 23, 2015*

**Algebra**

James walked 212 miles in 23 of an hour. What was his average speed, in miles per hour?
*November 21, 2015*

**conversions**

How to calculate the square meters of a roll that is 30500 LF x 117" x 75 gauge
*November 20, 2015*

**Physics**

A thin spherical shell of silver has an inner radius of 8.74 x 10-2 m when the temperature is 29.4 °C. The shell is heated to 145 °C. Find the change in the interior volume of the shell.
*November 15, 2015*

**Physics**

A copper (shear modulus 4.2 x 1010 N/m2) cube, 0.324 m on a side, is subjected to two shearing forces, each of magnitude F = 6.93 x 10 5 N (see the drawing). Find the angle (in degrees), which is one measure of how the shape of the block has been altered by shear deformation.
*November 14, 2015*

**Grammar check**

Hello, can you please check my answer. Which of the following sentences is written in the subjunctive mood? A. If the sun is shining, then I will wear sandals. B. It was the weekend, so she slept until noon. C. My health teacher recommends that I eat five servings of ...
*November 11, 2015*

**Math**

A marketing research firm wishes to determine if the residents of Caldwell, Idaho, would be interested in a new downtown restaurant. The firm selects a simple random sample of 120 phone numbers from the Caldwell phone book and calls each household. Only 62 of those called are ...
*November 9, 2015*