Friday

October 21, 2016
Total # Posts: 1,196

**Physics (Mechanics)**

Two blocks with equal masses m1 = m2 3.2 kg are connected via a pulley as shown in the above figure. Take the coefficent of kinetic friction to be 0.3 and the angle of the incline to be 40 degrees. Find the acceleration given that (Note: enter a negative value if the ...

*October 17, 2016*

**Physics (Mechanics)**

A block of mass m1 hangs vertically and is attached by a string to a block of mass m2 on a frictionless slope inclined at angle theta to the horizontal, as shown above. If m1 = 2.5 kg, it accelerates at -0.108 m/s2. If m1 = 0.8 kg, it accelerates at 2.888 m/s2. Determine the ...

*October 17, 2016*

**Mechanics**

Two blocks with equal masses m1 = m2 3.2 kg are connected via a pulley as shown in the above figure. Take the coefficent of kinetic friction to be 0.3 and the angle of the incline to be 40 degrees. Find the acceleration given that (Note: enter a negative value if the ...

*October 14, 2016*

**Mechanics**

A block of mass m1 hangs vertically and is attached by a string to a block of mass m2 on a frictionless slope inclined at angle theta to the horizontal, as shown above. If m1 = 2.5 kg, it accelerates at -0.108 m/s2. If m1 = 0.8 kg, it accelerates at 2.888 m/s2. Determine the ...

*October 14, 2016*

**geometry**

The measure of the supplement of an angle is three times the measure of the complement. Solve for the angle. I just want to find the equation but I do not understand it. I know that the angle is 40 degrees. Please teach me how to find the equation

*October 13, 2016*

**Statistics **

23 children born. What is the probability that 22 are boys & 1 is a girl?

*September 28, 2016*

**Math**

A cotton reel has a diameter of 3cm. 91 metres of cotton goes around it. How many times does the cotton go around the reel? And give your answer to the nearest ten

*September 28, 2016*

**Math**

John painted 1/2 of a pole white and 3/8 of it green. What is the fraction he painted?

*September 21, 2016*

**english**

I agree with Anonymous, in a portion of the story it reads " Luckily for her one of the talibs guarding the shack came to warn his superiors that we were refusing to leave until she returned. After hesitating for a moment, they pushed outside." In other words if the ...

*September 16, 2016*

**math**

A cylindrical tin of diameter 9cm and height 224cm is half filled with water.Find the volume of water in the tin.

*September 8, 2016*

**Calculus **

If θ is an acute angle and tan(θ)=5/12, then sin(θ)=??

*August 28, 2016*

**PHYSICS**

I agree that torque=I*ang_acc. But torque is not equal to 3g*radius but tension*radius. Do you agree with me bobpursley? Thanks.

*August 24, 2016*

**Physics**

please help me 1)In the movie The avengers, Captain America sees an alien speeder incoming. The speeder passes directly overhead at 3.65m. If he throws his shield straight up with a speed of 7.40 m/s from a height of 1.55 m above the ground (a) will the shied reach the speeder...

*August 24, 2016*

**Physics**

Totally confused on this question, Please help. 1)In the movie The avengers, Captain America sees an alien speeder incoming. The speeder passes directly overhead at 3.65m. If he throws his shield straight up with a speed of 7.40 m/s from a height of 1.55 m above the ground (a...

*August 24, 2016*

**PHYSICS/SCIENCE**

How much heat must be removed from 5.0g of water at 10°C to become ice at 0°C ?

*August 13, 2016*

**Physics/Science**

How much heat must be removed from 15.0g of water at 10°C to become ice at 0°C?

*August 13, 2016*

**physics**

an arrow is shot vertically upward 2 seconds later it is at a height of 42m with what velocity was the arrow shot, how long is the arrow in flight altogether

*August 1, 2016*

**physics**

a person in a hot air balloon ascending vertically at a constant rate of 12m/s drops a rock over the side when the balloon is 40m above the ground, what is the velocity of the rock just before it hits the ground, how long will it take the rock to reach the ground

*August 1, 2016*

**Chemistry**

if the solubilty of AgC2H3O2 is 5.0 x10^-2mol/L. What is the Ksp?

*July 29, 2016*

**physics**

a rock is dropped from a height of 20m above the ground when it hits the ground it leaves a hole 10cm deep with what speed does the rock hit the ground, and what is the magnitude of the rock's deceleration after it hits the ground

*July 28, 2016*

**Chemistry Grade 12**

If the concentration of I^-1 is found to be 2.4 x 10^-3 mol/L in a saturated solution of PbI2. What is the Ksp of PbI2?

*July 28, 2016*

**Chemistry Grade 12**

If the concentration of CN1- is found to be 1.4 × 10-6 mol/L in a saturated solution of AgCN, what is the Ksp of AgCN?

*July 27, 2016*

**Algebra/Calculus**

If x + y = xy = 3, what is x^3 + y^3? I have tried solving this using algebra alone, but my teacher told me to use complex numbers, and I don't know how to start. Can someone please guide me to the solution to this problem? Thanks Kevin

*July 11, 2016*

**Math**

5/8 of the students in my class were boys. When 6 girls joined the class, the number of boys equaled the number of girls. How many students were in my class then? "What's the formula for this problem?"

*July 3, 2016*

**Chemistry**

How many liters of 0.85 M HCl solution would react completely with 3.5 moles Ca(OH)2?

*June 20, 2016*

**Calculus**

which of the following is equivalent to integral (a,b) k*f(x)+C)dx where k and C are constants k integral (a,b)(f(x)+C)dx ***** intergral (a,b)kdx + intergral (a,b)f(x)dx+ intergral (a,b) Cdx k integral (a,b)f(x)+ integral (a,b) Cdx integral (a,b) kdx * integral (a,b) f(x) dx...

*June 3, 2016*

**Calculus**

Find F'(x) for F(x)= integral[from 1 to x] of cos(t^3)dt

*June 3, 2016*

**Calculus**

lim (x--> infinidy) x^2/ln(x)= -1 0 1 e does not exist

*June 3, 2016*

**Calculus**

Which of the following grows faster than e^x as x--> infinity x^4 ln(x) e^-x 3^x .5e^x

*June 3, 2016*

**help my son's math**

Sofia had 20 comic book and gave some of them to Heather.She uses a calculator to figure out that she gave away 0.15 of her comic book.How many comic book did she give to Heather!

*June 1, 2016*

**help my son's math**

Sofia had 20 comic book and gave some of them to Heather.She uses a calculator to figure out that she gave away 0.15 of her comic book.How many comic book did she give to Heather!

*May 31, 2016*

**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 don't 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-calculus **

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*