Posts by Alan

Total # Posts: 383

Chemistry
N-type silicon (Si) has been produced by doping with phosphorus (P). The charge-carrier population based on electrical conductivity measurments is determined to be 3.091*10^17 carriers/cm3 at room temperature. 1. Calculate the doping level of P (how much P has been added to ...

Chemistry
A glass of composition 85% SiO2 - 15% K2O is to be surface strengthened by ion exchange. To this end, two identical specimens approximately the size and shape of credit cards are soaked for the same amount of time at 850∘C. Sample A is soaked in NaCl and sample B is ...

Chemistry
Consider the heterogeneous equilibrium process shown below. C(s) + CO2(g) 2 CO(g) At 700.°C, the total pressure of the system is found to be 3.87 atm. If the equilibrium constant KP is 1.52, calculate the equilibrium partial pressures of CO2 and CO.

Algebra
What is x when 6(x+4)+4(x+5)=74

Algebra
What is x when 6(x+4)+4(x+5)=74

Algebra
Subtract. [2x/(x^2-y^2)]-[7/(y-x)] Thank you! :)

math
Lin-Yee is helping to set up a health clinic in Inuvik by collecting and shipping medical supplies from Calgary. She has found these shipping rates online: • regular rate: $2.10/lb • ship 101 to 500 lb, get a 20% discount • ship over 500 lb, get a 40% discount A...

math
A male moose is 2.6 m tall and 3.2 m long, with antlers that are 1.2 m across. An artist wants to carve scale models of the moose. She uses a scale factor of 1/30. a) What are the dimensions of the carvings to the nearest centimetre? b) How many carvings can she make using ...

math
The butcher shop sells a 3 lb package of chicken legs for $9.57. The supermarket sells chicken legs for $7.68/kg. Determine the price per kilogram that each store charges. Which store has the lower price per kilogram?

Pre-Calculus
A jet leaves an airport on a bearing of N 77* W and travels for 243 mi. It then turns and continues on a bearing of S 13* W for 104 mi. Find how far the jet is from the airport to 3 decimal places.

physics
Vf=Vi+at Vf=? Vi=19 m/s a=1.8 m/s^2 t=6.8 Vf is what are we are trying to find. So, Vf=(19 m/s)+(1.8 m/s^2)x(6.8s) Vf= 31.24 m/s But because of significant figures, our final answer would be 31 m/s.

math
Are those negative signs or subtraction signs? Just follow BEDMAS, Brackets, exponents, division, multiplication, addition subtraction. Do all those in that order and you should get the right number. It does not matter if you do Multiplication or divsion first.

math
how do i put 3.00x10 to the 8th into a calculator

Algebra
how do you use a table to find a solution to 4m - 5 = 11

algebra
Evaluate the following expression. 7^0

compound interest
If I invest $30000 at 10% compound interest for eighteen years how much will i get

geometry
A cone is created from a paper circle with a 90° sector cut from it. The paper along the remaining circumference of the circle is the base of the cone. Find the radius of the base of the cone. Round to the nearest hundredth.

Calculus
Sketch the graph of f(x)=(x^2 + 2)/x^2 - 4. Fund the vertical and horizontal asymptotes, the critical points, the points of inflection and the concavity.

Calculus
Sketch the graph of f(x)=x+2/x-4. Find the vertical and horizontal asymptotes, critical points, concave up/down, and inflection points.

Calculus
Sketch the graph of f(x)=-x^4 + 4x^3 - 16x + 16: Find the critical points, concave up/down, inflection points, vertical asymptotes and horizontal asymptotes.

Calculus
Find the price elasticity of demand. The demand function for the product is p=40-2x

Calculus
Find the relative extrema and absolute extrema if any. Use the first derivative test for the function f(x)=x^3-3x+2

Calculus
Find the equation of the tangent line to the graph of √(xy)=x-2y at (4,1)

Calculus
Find the points at which f(x)=x^2(x+1)^3 has a horizontal tangent.

Chemistry
What amperage is required to plate out .250 mol Cr from a Cr+3 solution in a period of 8.00 h?

math
a rectangular security area is enclosed with 200 ft of fencing. if this rectangular area is arranged so that the ratio of the length to the width is 5/3, find the dimensions.

Econ
The New York Times cost $0.15 in 1970 and $0.75 in 2000. The average wage in manufacturing was $3.23 per hour in 1970 and $14.32 in 2000. a. By what percentage did the price of a newspaper rise? b. By what percentage did the wage rise? c. In each year, how many minutes does a ...

Math
(340X60)/68=300 300MINS = 5H

Port st lucie
Can you help me find a link that tells me some information on history of Port St Lucie? Please answer if you see this.

Calculus
If 27 J of work are needed to stretch a spring from 18 cm to 24 cm and 45 J are needed to stretch it from 24 cm to 30 cm, what is the natural length of the spring?

calculus
find the rms value of the function i=15(1-e^-1/2t) from t=0 to t=4

Physics180
we don't know the mass of the astroid, how do we use the equation you have provided?

Physics180
Tidal forces can break apart objects that orbit too close to a planet, producing rings like those of Saturn. Consider an asteroid 600km in radius, 65mm from Saturn's center. What's the difference in gravitational acceleration between the two sides of the asteroid?

physics
A simple harmonic oscillator has spring constant = 8.8N/m , amplitude = 11cm , and maximum speed 4.6 m/s. what is the speed at x=6cm?

Physics
A spring with k=42N/m is mounted horizontally at the edge of a 1.2m high table. The spring is compressed 5cm and a 25g pellet is placed at its end. When the spring is released,m how far horizontally from the edge of the table does the pellet strike the floor?

Statistics
A young guy is setting up a date for his girlfriend. He has the option of going to Chicago, Indianapolis, or staying in Lafayette. If he chooses Chicago, he has 10 choices for a play and 100 choices for a restaurant. If he opts of Indianapolis, he has 5 choices for a play and ...

math
Wonderful help. Thank you.

math
Thanks for your help, I guess we took different approaches to this so now I'm a little confused. Is it possible to explain a little clearer?

math
From an observation tower that overlooks a runway, the angles of depression of point A, on one side of the runway, and point B, on the opposite side of the runway are 6 degrees and 13 degrees, respectively. The points and the tower are in the same vertical plane and the ...

Math
From an observation tower that overlooks a runway, the angles of depression of point A, on one side of the runway, and point B, on the opposite side of the runway are, and , respectively. The points and the tower are in the same vertical plane and the distance from A to B is 1...

math
Yes but why is it 45 degrees? I'm dividing 8 into 16 = .5 then cos-1 .5 = 60. Nothing I do is giving me 45 degrees. Hope you get notified when a thread is updated, I'm inclined to repost this incase. Thanks again for your great answering.

Mathematics
thank you

Mathematics
Hi, Can someone check this for me .. please A tuning fork has a wavelength 0f 136 centimetres. Given that the speed of sound is 340 metres per second what is the frequency of the tuning fork ?? Frequency = speed / wavelength Then 340 / 1.36m (136cm) = 250 Hz Thank you try to ...

math
2/27(x-3)√((x^2-6x+23)/y)rearrange the equation to make y the subject

algebra
collect all like terms 3x^2-5x^2+12y-3y+8x =-2x^2+9y+8x

Algebra 1
the answer is distance over time. total distance is 1500 miles total time is 3.5 hours. 1500/3.5=428.57 mph.

maths
(a)(i)use the composite rule to differentiate the function f(x)=(x^2-6x+23)^(3/2). (ii)use the composite rule and your answer to part (a)(i) to show that the function g(x)=(x-2)/(x^2-6x+23)^(3/2) has derivative g'(x)=(5+9x-2x^2)/(x^2-6x+23)^(5/2). (iii)find any staionary ...

physics
An inflated basketball has a gauge pressure of 9.0 lb/in^2. What is the actual pressure inside the ball?

physics
A 70 kg person sits on a 3.6 kg chair. Each leg of the chair makes contact with the floor in a circle that is 1.5 cm in diameter. Find the pressure exerted on the floor by each leg of the chair, assuming the weight is evenly distributed.

calculus
An airplane at a height of 2000 meters is flying horizontally, directly toward an observer on the ground, with a speed of 300 meters per second. How fast is the angle of elevation of the plane changing when this angle is 45 degrees?

Physics
Pushing on the pump of a soap dispenser compresses a small spring. When the spring is compressed 0.55 cm, its potential energy is 0.0035 J. What is the force constant of the spring? What compression is required for the spring potential energy to equal 0.0094 ?

physics
You raise a bucket of water from the bottom of a deep well. If your power output is 128 W, and the mass of the bucket and the water in it is 6.00 kg, with what speed can you raise the bucket? Ignore the weight of the rope.

physics
Never mind, i figured it out.

physics
A new record for running the stairs of the Empire State Building was set on February 3, 2003. The 86 flights, with a total of 1576 steps, was run in 9 minutes and 33 seconds. If the height gain of each step was 0.20 m, and the mass of the runner was 68 kg, what was his average...

physics
A 1.1 kg block is held against a spring of force constant 2.0×10^4 N/m, compressing it a distance of 0.20 m. How fast is the block moving after it is released and the spring pushes it away? v=____m/s

pyhsics
never mind, i figured out how to do this problem 1. K = 11J 2. v = 9.1m/s 3. W = 14J the wording was just alittle bit confusing

pyhsics
At t= 1.0s, a 0.61 kg object is falling with a speed of 6.0 m/s. At t= 2.0s, it has a kinetic energy of 25 J. 1. What is the kinetic energy of the object at t= 1.0s? 2. What is the speed of the object at t= 2.0s? 3. How much work was done on the object between t= 1.0s and t= 2...

Physics
A small plane tows a glider at constant speed and altitude. If the plane does 2.00X10^5 J of work to tow the glider 165 m and the tension in the tow rope is 2660 N, what is the angle between the tow rope and the horizontal?

physics
A 55-kg packing crate is pulled with constant speed across a rough floor with a rope that is at an angle of 44.7 degrees above the horizontal. If the tension in the rope is 155 N, how much work is done on the crate to move it 9.0 m? *looking for W=__J

Physics
Early one October, you go to a pumpkin patch to select your Halloween pumpkin. You lift the 2.8 kg pumpkin to a height of 1.4 m, then carry it 50.0 m (on level ground) to the check-out stand. Calculate the work you do on the pumpkin as you lift it from the ground? and How much...

Physics
531684.027J

AP PHYSICS
In a Young's double-slit experiment, the angle that locates the second-order bright fringe is 3.0°. The slit separation is 4.8 10-5 m. What is the wavelength of the light?

Physics
At t=0, a wave disturbance has the waveform that is shown in a figure. The wave has a velocity of 500.0 m/s to the left. What's the values for k and ω if the wave equation is to be written in the form: y(x,t)=A cos(kx±ωt+φo). What is the value for k, ...

Physics
Thanks.

Physics
Two waves are combined to form this standing wave equation of y(x,t) = (3 mm)sin[x/(2 m]cos[(100 rad/s)t] a. What's the amplitude of the right moving wave and left moving wave? b. What's the wavelength of the right moving wave and left moving wave? c. What's the ...

AP Physics
At a height of 5 meters above the surface of a freshwater lake, a sound pulse is generated. The echo from the bottom of the lake returns to the point of origin 0.140 s later. The air and water temperatures are 20°C. How deep is the lake?

Science Physics
A rubber ball of mass m1= 10kg is moving to the right with speed v1= 10m/s. it collides elastically with another ball of mass m2= 50kg, which is sitting at rest. m2 is larger than m1, what are the speeds of the balls, v1 and v2 after the collision?

writing paper for political science
Ok then I will start at that point.

writing paper for political science
Since it only wants recent history I gather then I don't need to go back to far ago. So I should just stick to the most recent events? Or should I start with the korean war? Would it be wise to mention the Korean war briefly if it is important to the current events?

writing paper for political science
Thanks of the responses. I came up with the country in order to do on the conflict with North Korea. Yeah I could use a tip on researching what about the conflict I should focus on. I got a bit overwhelmed. and I also was lost on how to cite sources into a paper with footnotes...

writing paper for political science
Confused on what do to do for this paper I have to write for a class here in a community college. I am to choose a country in asia, africa or Latin America like say South Korea. I am to research recent history and contemporary situation. Identify and explain using factual ...

business
18. Which of the following is not a ramification of too much or too little status in an organization? a. it inhibits communication b. solidarity is not developed c. it interferes with work d. it causes resentment and conflict e. it causes communication underload

5th grade
Reggie and jay go for a walk every morning. Reggie walks 2 1/4 jay walks 1 3/8 miles less than reggie what is the total distance they walk every morning

Chemical Engineering
I got the same answer

Physics
can you tell me the magnitude of the force P and the mass of block C? show work please

math
distance over time. 18/2=9 so is traverling at 9 feet per second multiply by the amount need to turn one second into an hour and u will have your answer.60 x 60 just a clue to help.

Astrology / Physics
The calculations/concepts here are actually physics.

Astrology / Physics
How do we calculate the radial velocity after the recession velocity is known?

Chemistry
Does methanol absorb UV light?

Chemistry
Does water and methanol absorb light in the UV-Vis region?

algebra
Find the function value. f(x)=x^3 f(-8)=

algebra
Given the function k described by k(x)=8x, find each of the following. k(-13)= k(6)= k(24)=

Chemistry
In the reaction: Protection of 1-Phenylethanol by 3,4-Dihydro-2H-pyran, 1-phenylethanol, 3,4-Dihydro-2H-pyran and anhydrous ether were added first and stirred in ice-water bath before acid catalyst p-toluenesulfonic acid monohydrate was added. The reaction was kept at 0 deg ...

math 5th grade
Answer would actually be 6 because 48 divided by 8 is 6

math 5th grade
Answer would actually be 6

Statistics
One of the tests for Outlier is anything greater or smaller than 1.5 IQR. Why is 1.5 chosen to be the benchmark, instead of 2 or 1 IQR?

Chemistry
An NMR spectrum of fumaric acid in acetone was run. The following results were obtained: 1 sharp peak with 5 splittings at around 2 ppm (belonging to acetone) 1 broad peak at 3.789 ppm (integration 0.63) 1 sharp peak at 6.779 ppm (integration 1.00) (belonging to CH of fumaric...

Chemistry
An NMR spectrum of fumaric acid in acetone was run. The following results were obtained: 1 sharp peak with 5 splittings at around 2 ppm (belonging to acetone) 1 broad peak at 3.789 ppm (integration 0.63) 1 sharp peak at 6.779 ppm (integration 1.00) (belonging to CH of fumaric ...

Chemistry
In general, what are the conditions required for Schiff's Base to polymerise?

Chemistry
Sorry. What I meant was: How do we improve the efficiency of Flash Column Chromatography?

Chemsitry
How do we improve the efficiency of Column Chromatography?

Pyschology
the determining factors of gender identification and gender roles o State the factors that determine gender identity. o Explain how a person’s masculine and feminine traits can be described using the continuum of masculinity-femininity

Biochemistry
Is ATP an allosteric inhibitor for protease?

Biology / Biochemistry
How will the conformation of an Enzyme (a protease) be affected when the amino acid residue is substituted with glutamate instead of glutamine?

Chemistry
Beside the usual method of titrating with KMNO4, what is/are the alternative method/s to test for the presence/amount of oxalate in a compound?

math
-8<3x-5<-4 -8<3x-5 and 3x-5<-4 3x-5>-8 3x<1 3x>-3 x<1/3 x>-1 therefore 1/3>x>-1

Chemistry
Is Al(OH)3 soluble in KOH or K2C2O4•3H2O?

Math 30
Yes, 2^9.

Chemistry
Why is heating required for this formation: 6NaOH (aq) + Al2(SO4)3 (aq) ¨ 2Al(OH)3 (s) + 3Na2SO4 (aq)? Wouldn't freezing favour the formation of Al(OH)3 since freezing lower the KSP and more Al(OH)3 would precipitate?

Chemistry
This is the equation for the formation of Al(OH)3: 6NaOH (aq) + Al2(SO4)3 (aq) ¨ 2Al(OH)3 (s) + 3Na2SO4 (aq) Would any side products be formed if NaOH was added quickly into Al2(SO4)3?

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