Saturday
December 3, 2016

Posts by kevin

Total # Posts: 1,205

Math
You do not have enough 6-inch beads to make the rope, so you will use 10-inch beads instead. Write and solve an inequality that represents the number of 10-inch beads that you can use.
December 2, 2016

physics
A spring gun shoots out a plastic ball at speed v0. If the ball's speed is increased by a factor of 2, what distance must the spring have been compressed?
November 18, 2016

Math
How many volleyball games would Rana have to schedule if there were 10 teams in the league and each team played each other twice?
November 9, 2016

pre-calculus
Assume that the number of bacteria follows an exponential growth model: P(t)=P0ekt . The count in the bacteria culture was 900 after 20 minutes and 1600 after 30 minutes. (a) What was the initial size of the culture? (b) Find the population after 80 minutes. (c) How many ...
November 7, 2016

Physics (Mechanics)
A student of mass M = 62 kg takes a ride in a frictionless loop-the-loop at an amusement park. The radius of the loop-the-loop is R = 19 m. The normal force by the track on the student at the top of the loop-the-loop is N1 = 100 N Find the speed of M at the top of the loop. ...
October 26, 2016

Physics (Mechanics)
A 905 kg car moves in a circle of radius 13.1 meters in a flat parking lot. If the car can travel at 9.1 m/s without slipping, what is the force of friction between each tire and the parking lot? What is the coefficient of friction between each tire and the lot? (Remember ...
October 26, 2016

Physics
You push a 1kg block against a spring with spring constant k = 100 Nmon a horizontal table top. The spring is compressed to 0.2m away from its relaxed length, and then the block is released. If the horizontal table top has a coefficient of kinetic friction of 0.2, how much ...
October 23, 2016

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

math
deez nuts
March 14, 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

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