Saturday

October 25, 2014

October 25, 2014

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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