Sunday

March 1, 2015

March 1, 2015

Total # Posts: 1,531

**magnets**

A particle of charge +q and mass m is initially launched at speed v in a region with a constant, uniform magnetic field of magnitude B. If the particle launched in a direction perpendicular to the magnetic field, by the time the particle has traveled a distance d, the work ...
*December 18, 2013*

**AP CALC**

find an equation of the tangent line to the graph of x^4-2y^2=1 at the point (2,4)
*December 17, 2013*

**AP CALC**

Suppose that g(x)=h(x)/f(x) and f(3)=5, h(3)=6, g'(3)=4 and f'(3)=1. find h'(3).
*December 17, 2013*

**Math**

Alan, Gil, and Deb's point score in a video game was in a ratio of 2:3:4. Deb scored 114,400 points. A) how many points did Gil score? B) how many points did all of them score? i dont know how to do this would you please help me, thank you
*December 17, 2013*

**electricity and magnets**

A thick metal slab carries a current I. A uniform magnetic field B points perpendicular to the slab (and into the page). If point P on the slab is at a higher potential than point , what can we say about the charge carriers that produce the current in the slab?
*December 17, 2013*

**Physics**

Two thin, infinitely long, parallel wires are lying on the ground a distance d=3cm apart. They carry a currentTwo thin, infinitely long, parallel wires are lying on the ground a distance d=3cm apart. They carry a currentTwo thin, infinitely long, parallel wires are lying on ...
*December 12, 2013*

**please help me!! with this science!!!!!**

Smeh, don't blame her. Do your work next time.
*December 11, 2013*

**physicS IMP PLS**

@Greco I tried it and it workrd for a and c and for Fy but Fx was wrong!why did you use alpha? please help with this question!
*December 9, 2013*

**physics I'M STUCK PZL HELP**

is the "u" the ejected fuel in m/s instead of km/s?
*December 8, 2013*

**physics I'M STUCK PZL HELP**

in the equation above what is the "ln"?
*December 8, 2013*

**PHYSICS IMP PLS**

@Hil if you had calculated correctly it seem to be right
*December 8, 2013*

**PHYSICS IMP PLS**

it's simple 10%/2 because 145=290/2 and it said "assume the burn rate is constant" so V=Vex*ln(1/(1-%/2)) for your case V=2000*ln(1/(1-0.05)) a=V/145
*December 8, 2013*

**Writing Skills**

Thank you so much ^_^
*December 4, 2013*

**Writing Skills**

i think 1 is 2 2 is 2 3 is 2 are they correct?
*December 4, 2013*

**Writing Skills**

1) Frequently their renovation need to be completely redone. 1 need 2 needed 3 were needing 4 will have been needing 5 needs 2)If we were teenagers at the time these licenses signified our passage to adulthood. 1 time these licenses 2 time, these licenses 3 time; these ...
*December 4, 2013*

**Science**

How far does a wave travel in three cycles?
*December 3, 2013*

**Science**

The distance from the crest of a wave to the next crest is 10 centimeters. The distance from a crest of this wave to a trough is 4 centimeters. a. What is the amplitude of this wave? b. What is the wavelength of this wave?
*December 3, 2013*

**World History**

How do the beliefs of being a Christian and being a Crusader contradict each other? How are the ideas of the Crusades used today for both Christians and Muslims?
*December 1, 2013*

**Solar**

Someone please help me. I keep getting the same wrong answer (38.4). Please help ASAP. Thanks.
*November 29, 2013*

**Solar**

All, anything on this yet? please help!!! Thanks in advance again./Anon1...didn't know there was an Anon already
*November 29, 2013*

**Solar**

Greeting All, please assist with the below. Thanks. The spectral power density of a solar simulator is given by: P(λ)=7.5∗1015λ−2.25∗109 [Wm^-2m^-1] for 300nm<λ<500nm P(λ)=2.25∗109−1.5∗1015λ [Wm^-2m^-1] for ...
*November 29, 2013*

**History**

Who were the Seljuk Turks? What did they do?
*November 25, 2013*

**ET3034TUx Solar Energy**

Consider a crystalline PV module with the following output parameters mentioned at STC (Standard Testing Condition) conditions by the manufacturer. Pmax = 250W Voc = 50V Isc = 6A NOCT = 40°C Temperature coefficient of power = -1W/°C a) If the ambient temperature falls ...
*November 25, 2013*

**Chemistry**

Please help! Is 4-methylphenol acid, basic or neutral?
*November 25, 2013*

**Language Arts**

Have you ever wanted to know what people said and thought about you when you weren't around? If you could disguise yourself in some way and be around the people you know, how would you carry it out? Describe your ideal disguise and a scenario that you imagine would take ...
*November 24, 2013*

**Language Arts**

Thank you! That's just what I needed tips! :-)
*November 24, 2013*

**Language Arts**

describe a soggy, wet day. use sensory details.
*November 24, 2013*

**Physics**

can you help me with the problem of TURNTABLE SOLUTIONS???
*November 24, 2013*

**Physics**

thanks Elena you're the best ;)
*November 24, 2013*

**Physics**

TORQUE, ROTATION AND TRANSLATION A Yo-Yo of mass m has an axle of radius b and a spool of radius R . Its moment of inertia about the center can be taken to be I=(1/2)mR2 and the thickness of the string can be neglected. The Yo-Yo is released from rest. You will need to assume ...
*November 24, 2013*

**Physics**

it didn't work :(
*November 24, 2013*

**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*

**Math**

i dont understand that problem the one that is up there i need the answer like now though
*November 15, 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*

**science**

i think
*October 25, 2013*

**science**

destin y is rong
*October 25, 2013*

**science**

desiny isn't right
*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*

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