Saturday
October 25, 2014

Posts by ANON


Total # Posts: 1,387

Physics
TURNTABLE SOLUTIONS A gyroscope consists of a uniform disc of mass radius M= 1 kg and radius R= 0.3 m . The disc spins with an angular speed ω= 400 rad⋅s-1 as shown in the figure below. The gyroscope precesses, with its axle at an angle 30∘ below the ...
November 24, 2013

water treatment
A wastewater treatment plant based on activated sludge with biological phosphate and nitrogen removal via pre-denitrification. The influent flow (dwf) is 30,000 m3/day and the influent BOD concentration is 300 mg BOD/l. The suspended solid concentration in the influent is 150 ...
November 24, 2013

water treatment
A wastewater treatment plant based on activated sludge with biological phosphate and nitrogen removal via pre-denitrification. The influent flow (dwf) is 30,000 m3/day and the influent BOD concentration is 300 mg BOD/l. The suspended solid concentration in the influent is 150 ...
November 24, 2013

water treatment
Which is correct for this trickling filter? a)Due to the low BOD loading rate the biomass growth will be too little. Methanol needs to be dosed to keep the biomass alive. b)Due to the high BOD loading rate the filter might clog. This can be prevented by effluent recycling in ...
November 24, 2013

Calc
At noon, ship A is 100km west of ship B. Ship A is sailing south at 30km/h and ship B is sailing north at 15km/h. How fast is the distance between the ships changing at 4:00pm?
November 23, 2013

Chemistry
PLEASE HELP! I was just wondering why it is important to add an NaOH pellet to a nucleophile containing solution with ethanol before adding an electrophile.
November 20, 2013

waste water treatment
3G man?
November 20, 2013

waste water treatment
screen -->coarse material grit chamber -->xxx primary sedimentation -->xxx anaerobic tank-->xxxx anoxic tank--->xxxx aerobic tank-->nitrification final clarifier-->xxxx sludge dewatering -->remove water from the sludge help me with Q3C Q3D Q3E
November 20, 2013

Science please
Kinetic energy and Potential energy are often considered to be forms of mechanical energy. List three other forms of energy and state a source for each.
November 19, 2013

Chemistry
(a) Which of the following are requirements for anionic polymerization? --A double bond --End groups which can react by releasing a small molecule --A strong base to initiate the reaction --A strong acid to initiate the reaction --An electron-withdrawing group near the double ...
November 19, 2013

Chemistry
finally i got it F Cl COOCH3
November 19, 2013

Chemistry
COOCH3 and CH2CH3 is wrong
November 19, 2013

Chemistry
COOCH3 is wrong
November 19, 2013

Chemistry
Did you find the last quetion of homework 11?
November 15, 2013

Chemistry
thanks
November 15, 2013

Chemistry
@Drew can you give me the formula?
November 15, 2013

Chemistry
1- 7.36e-2 189 2-metal Solid hydrogen has a half filled s-band insulator Solid helium has a filled s-band 3-1.13 semiconductor 4-Ionization of phosphorus requires some minimum temperature n_type The concentration of conduction electrons is fixed by the concetration of ...
November 15, 2013

Chemistry
if someone help with those questions I'll post all the rest of answers
November 15, 2013

Chemistry
3//1.13 ev semiconductor 4//4th option n-type 4th option intrinsic
November 15, 2013

Chemistry
a)The Young's modulus for a material is 5.0*10^10 N/m2. The material is stretched to a strain of 4.0*10^-3. How much elastic energy will be expended? (Express your answer in J/m3) Knowing that the energy associated with the formation of 1 mole of vacancies in copper (Cu) ...
November 15, 2013

Solar Energy
it is wrong! I'm sure!
November 14, 2013

Biology
Please help! i was wondering why a genome size determined in a lab would be smaller than that of the actual. thanks
November 12, 2013

Biochemistry
Please help! i was wondering why a genome size determined in a lab would be smaller than that of the actual. thanks
November 12, 2013

Physics please HELP
1- 19.2E-19 2-??? 3-1 4-4.8E-5 5-3.84e-23 6-h-(2*ke*lambda*q)/(l*ks) 7-(E*q)/(m*g) 8-D 9-7e-6 10-3.6e7 11-??? 12-3rd option 13-54e9 14-408.5E-12 15-4.902E-9 16-2.451E-9 17-6000 18-96E-17 19-1053787047200878.1558726673984632 20-increase 21-stay the same 22-increase 23-increase ...
November 8, 2013

Science
1. The sporophyte generation produces spores that grow into a(n) (1 point) gametophyte. gymnosperm. angiosperm. pupa. 2. Placental mammals develop (1 point) in an egg laid in water. in a pouch on the mother’s body. inside the mother’s body. inside an amniotic egg. 3...
November 6, 2013

Chemistry
How would I extract benzophenone from acetylsalicylic acid? thanks
November 6, 2013

Chemistry
If I have 1.00 mM NaCl and 4.32 mM NaCl, how do I calculate the ionic strengths of each? Thanks
November 4, 2013

PHYSICS(HELP)
For v_1, you have sqrt(v_0^2 - 2*G*(L(1 - cos(alpha)))), right? For tension, you use T = Fgravitational + Fcentrifugal, where Fg = m*g*cos(alpha) and Fc = m*(v_1)^2/L. Then for max height you'll have something like this: (v_1 * sin(alpha))^2/(2*G), and for alpha you use ...
November 1, 2013

PHYSICS(HELP)
Well, think a little... If you're at an infinity distance, your gravitational potential must be zero, as you see: -mMG/distance, if distance is infinity, it doesn't metter -mMG as somehow it is some constant. So, you have some velocity at "infinity" so you ...
November 1, 2013

ET3034TUx Solar Energy
Thank you! but it's not only a) !!
October 29, 2013

ET3034TUx Solar Energy
Which of the following processes is used in order to fabricate mono-crystalline silicon? a) The Czochralski process b) Silicon ribbon process c) The float-zone process d) The silicon casting process
October 29, 2013

Chemistry
How do I determine which atom in a molecule would be the strongest base? Thanks
October 28, 2013

Solar Energy Please Help
@foxman thinks
October 26, 2013

Mathhh
Use substitution to solve the system of equations given below. 8x - 4y = 16 2x - y = 4
October 25, 2013

Chemistry
Help! If I have 0.0031 absorbance/sec, how would I convert this to absorbance/minute? Thanks
October 22, 2013

calculus
I really need help on this!!!!
October 21, 2013

calculus
Let y =x arcsin x, x is an element of ]-1, 1[. Show that d^2y/dx^2 = 2-x^2/(1-x^2)^3/2
October 21, 2013

Math- Urgent
2e = 4e -16 -4e -4e -2e=-16 /-2 /-2 e=8
October 21, 2013

math
x+4=-8 do you have to solve for x?
October 21, 2013

math
I completely forgot the rules but.... if you have ((1-x)^1/2)^2 Then would you multiply the exponents to get 2/2 = 1 or add them to get 3/2
October 21, 2013

algebra
2 cm. i think
October 21, 2013

Math please help
You have to set up a proportion. 2/3 = 12/x solve for x 2x=36 x=18
October 21, 2013

algebra
3. I think Because you take the total number of problems (48) and divide that by 2 = 24. Then divide that by 2 = 12. And divide that by 2= 6. And divide that by 2 = 3. He needs to complete 3 problems on the first day for the number of problems completed to double each day for ...
October 21, 2013

math
please help me. I don't know what I am doing wrong
October 21, 2013

math
I tried to use the quotient rule but I get stuck simplifying it. I got (sqrt1-x^2)(1/sqrt1-x^2) - (x+arcsinx)(1/2(1-x^2)2x) / (sqrt1-x^2)^2
October 21, 2013

math
*use the quotient rule
October 21, 2013

math
I get stuck on the second derivative, trying to get it to equal 2-x^2/(1-x^2)^3/2. I think that from my first derivative, you have to sure the quotient rule
October 21, 2013

math
xarcsinx*
October 21, 2013

math
Sorry i meant x arrsin x. So I thought the first derivative of that would be x/sqrt1-x^2 + arcsinx
October 21, 2013

math
Let y = arcsin x, x is an element of ]-1, 1[. Show that d^2y/dx^2 = 2-x^2/(1-x^2)^3/2
October 21, 2013

math
ok thank you.
October 21, 2013

math
do you just change all the signs of the terms? if so, why is this necessary?
October 21, 2013

math
Thanks. I was wondering, why is it "+ sin x" in the second step?
October 21, 2013

math
cos2x-sinx=0. Factor and solve for sinx
October 21, 2013

physics
Part b) is working forces. So you have centripetal acceleration = N-kx where kx is the spring force. cent acc = mv^2/r so us a)to derive this.
October 19, 2013

physics
Use this link it shows the question you are solving , but it has slightly different parameters ie the equilibrium of the spring. It show that you need GPE + EPE = KE + GPE + EPE ie TOP=SIDE. You can then rearrange this to get everything on one side except v (your speed). I ...
October 19, 2013

physics
Use this link it shows the question you are solving , but it has slightly different parameters ie the equilibrium of the spring. It show that you need GPE + EPE = KE + GPE + EPE ie TOP=SIDE. You can then rearrange this to get everything on one side except v (your speed).
October 19, 2013

Can someone check these answer for me?
The correct answers are 1. B 2. A 3. C 4. D 5. C I just took this and got 100%
October 17, 2013

Solar Energy Help ASAP
0.674 can someone help with the others quetion? Q4 5 6 7?
October 17, 2013

ET3034TUx Solar Energy
The current density of an ideal p-n junction under illumination can be described by: J(V)=Jph−J0(eqVkT−1) where Jph is the photo-current density, J0 the saturation-current density, q the elementary charge, V the voltage, k the Boltzmann's constant, and T the ...
October 16, 2013

ET3034TUx Solar Energy
The width of the space charge region at a p-n junction is reduced by applying a voltage bias over the p-n junction. What is the correct statement on both the bias voltage and the p-n junction? a)The voltage is a forward bias and the diffusion of the majority charge carriers ...
October 16, 2013

Physics
oscillating block ans D) 1.2
October 15, 2013

Physics
When you push down on the handle of a bicycle pump, a piston in the pump cylinder compresses the air inside the cylinder. When the pressure in the cylinder is greater than the pressure inside the inner tube to which the pump is attached, air begins to flow from the pump to the...
October 15, 2013

Physics
A sample of a monatomic ideal gas is originally at 20 °C. Calculate its final temperature of the gas if the pressure is doubled and volume is reduced to one-fourth its initial value.
October 15, 2013

Science
Humans developed antibiotics to fight bacterial infections. However, some antibiotics are no longer efective in killing the bacteria they once killed. How does the theory of evolution explain this?
October 14, 2013

physics
A 660 kg car is being pushed along a flat parking lot at a constant speed of 1.52 m/s. The coefficient of friction between the road and the car is 0.31. What force is being used to push the car?
October 13, 2013

Quantum Physics
Wrong !!!! I try it!!
October 12, 2013

Quantum Physics
Ive checked and its neither phi=2bt nor 2b
October 12, 2013

Quantum Physics
Q 7 and 8 Please!!!
October 12, 2013

Quantum Physics
3b - C 3c - 0
October 12, 2013

Chemistry
12.111111111
October 12, 2013

physics
Consider an ideal spring that has an unstretched length l0 = 3.9 m. Assume the spring has a constant k = 20 N/m. Suppose the spring is attached to a mass m = 6 kg that lies on a horizontal frictionless surface. The spring-mass system is compressed a distance of x0 = 1.7 m from...
October 11, 2013

Physics
A conical pendulum is constructed from a rope of length l and negligible mass, which is suspended from a fixed pivot attached to the ceiling. A small ball of mass m is attached to the lower end of the rope. The ball moves in a circle with constant speed in the horizontal plane...
October 10, 2013

reading
TKU :)
October 8, 2013

reading
How is grandmother's dream different from reality? >Last night I dreamed of an old lover I had not seen him in forty years. When I awoke, I saw him on the street. His hair was white, his back was stooped. How could I say hello? He would have puzzled all day about who ...
October 8, 2013

Physics
A person is standing on the edge of a cliff of height h= 24 m. She throws a stone of mass m=0.2 kg vertically down with speed v0= 10 m/s (stone 1) and another stone of the same mass vertically up at the same speed (stone 2). The gravitational acceleration is g=10 m/s2. (a) ...
October 6, 2013

physics
We are standing at a distance d=15 m away from a house. The house wall is h=6 m high and the roof has an inclination angle β=30 ∘. We throw a stone with initial speed v0=20 m/s at an angle α= 35 ∘. The gravitational acceleration is g=10 m/s2. (See figure...
October 6, 2013

physics
We are standing at a distance d=15 m away from a house. The house wall is h=6 m high and the roof has an inclination angle β=30 ∘. We throw a stone with initial speed v0=20 m/s at an angle α= 35 ∘. The gravitational acceleration is g=10 m/s2. (See figure...
October 6, 2013

physics
An elevator is stopped at the ground floor. It starts moving upwards at constant acceleration a>0 for 5 seconds. It then keeps a constant speed for 35 seconds. Finally, it slows down with an acceleration of the same magnitude (but opposite direction) −a , until it ...
October 5, 2013

physics
An elevator is stopped at the ground floor. It starts moving upwards at constant acceleration a>0 for 5 seconds. It then keeps a constant speed for 35 seconds. Finally, it slows down with an acceleration of the same magnitude (but opposite direction) −a , until it ...
October 5, 2013

physics
We are standing at a distance d=15 m away from a house. The house wall is h=6 m high and the roof has an inclination angle β=30 ∘. We throw a stone with initial speed v0=20 m/s at an angle α= 35 ∘. The gravitational acceleration is g=10 m/s2. (See figure...
October 5, 2013

physics (it's rather urgent help is appreciated
no
October 5, 2013

physics (it's rather urgent help is appreciated
yeah
October 5, 2013

physics (it's rather urgent help is appreciated
@ss01 for the inclined wall stone throw
October 5, 2013

physics (it's rather urgent help is appreciated
@ss01 did you manage to find the time?
October 5, 2013

physics
i can't quite get the value of t
October 5, 2013

physics
thank you so much, sorry for being rather spamy so to say
October 5, 2013

physics (it's rather urgent help is appreciated
We are standing at a distance d=15 m away from a house. The house wall is h=6 m high and the roof has an inclination angle β=30 ∘. We throw a stone with initial speed v0=20 m/s at an angle α= 35 ∘. The gravitational acceleration is g=10 m/s2. (See figure...
October 5, 2013

Chemistry
Calculate the magnitude of the cohesive energy of potassium iodide (KI). The ionic radii of K+ and I−, are 152 pm and 206 pm, respectively. Assume the Born exponent n is 10. Assume a Madelung constant of 1.7. Please report your answer in kJ/mol or how to calculate it.
September 28, 2013

Chemistry
Calculate the magnitude of the cohesive energy of potassium iodide (KI). The ionic radii of K+ and I−, are 152 pm and 206 pm, respectively. Assume the Born exponent n is 10. Assume a Madelung constant of 1.7. Please report your answer in kJ/mol or how to calculate it.
September 28, 2013

Bio/Math
A population of glasswing butterflies exhibits logistic growth. The carrying capacity of the population is 200 butterflies, and rmax, the maximum per capita growth rate, of the population is 0.10 butterflies/(butterflies*month). Calculate the maximum population growth rate for...
September 22, 2013

AP Bio; PLEASE HELP!
if a fish farmer wanted to harvest his fish so that it recovered at the maximum rate, where should the population be maintained? There is a graph number of weeks vs. numbers of fish. and A B C and D marked on the graph. How do I figure it out??
September 22, 2013

Chemistry
Finally I found it.We have to do this : wavelength=h/P P^2=2*m*E P=sqrt(2*m*E) E = joule h = Planck's constant m = kg
September 18, 2013

Chemistry
Can you write the result because i found 5.067e-7 and it's wrong.I try it many time in diffrent ways baut I finished with the some result!
September 18, 2013

Chemistry
Calculate the wavelength of a proton with energy 2.45 eV. Please some help!
September 18, 2013

Classical Mechanics
thank you it help me!
September 18, 2013

Classical Mechanics
Mary wants to throw a can straight up into the air and then hit it with a second can. She wants the collision to occur at height h=5.0 m above the throw point. In addition, she knows that she needs t1=4.0 s between successive throws. Assuming that she throws both cans with the...
September 18, 2013

Chemistry
Calculate the wavelength of a proton with energy 2.45 eV.
September 15, 2013

BIOLOGY
yes, no, yes is correct
September 12, 2013

science
Green algae grow in the fur of the South American sloth. The green algae provide camouflage for this tree-doweling mammal, and from the fur and skin of the sloth the algae obtain moisture. A moth also lives in the fur. The moth larvae provide waste material used by the algae ...
September 11, 2013

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