Thursday

August 28, 2014

August 28, 2014

Total # Posts: 960

**mechanics**

two bodies of mass m1 and m2 are attached to two ends of a string which passes over a massless and frictionless pulley. find the acceleration of the bodies and the tension of the string. m1 is bigger than m2
*November 22, 2012*

**math**

for n repeated independent trials, with constant probability of success p for all trials, find the probability of exactly x succes n=20,p=1/8, x=2 I know the answer but I do not know how to get to that. Answer is 0.268 should I reduce fraction?
*November 20, 2012*

**math**

for n repeated independent trials, with constant probability of success p for all trials, find the probability of exactly x succes n=5,p=1/3, x=4
*November 20, 2012*

**math**

Beth Dahlke is taking a ten question multiple choice test for which each question has three answer choice only one of which is correct. Beth decides on answers by rolling a fair die and making the first answer choice if the die shows 1 or 2 the second if it showes 3 or 4 and ...
*November 20, 2012*

**math**

for n repeated independent trials, with constant probability of success p for all trials, find the probability of exactly x succes n=5,p=1/3, x=4
*November 20, 2012*

**math**

A game show contestant is offered the option of receiving a computer system worth $2300 or accepting a chance to win either a luxary vacation worth $5000 ora boat worth $8000.If the second option is chosen the contestant"s probability of winning the vacation or the boat ...
*November 19, 2012*

**Physics**

Suppose a 47-N sled is resting on packed snow. The coefficient of kinetic friction is 0.14. If a person weighing 670 N sits on the sled, what force is needed to pull the sled across the snow at constant speed?
*November 17, 2012*

**math**

Therese Felser manages a grocery warehouse which encourages volume shopping on the part of its customers. Therese has discovered that, on any given weekday 70 percent of the customer sales amount to more than $ 100. That is any given sale on such a day has a probability of 0....
*November 17, 2012*

**math**

Therese Felser manages a grocery warehouse which encourages volume shopping on the part of its customers. Therese has discovered that, on any given weekday 70 percent of the customer sales amount to more than $ 100. That is any given sale on such a day has a probability of 0....
*November 17, 2012*

**math**

Therese Felser manages a grocery warehouse which encourages volume shopping on the part of its customers. Therese has discovered that, on any given weekday 70 percent of the customer sales amount to more than $ 100. That is any given sale on such a day has a probability of 0....
*November 16, 2012*

**math**

Therese Felser manages a grocery warehouse which encourages volume shopping on the part of its customers. Therese has discovered that, on any given weekday 70 percent of the customer sales amount to more than $ 100. That is any given sale on such a day has a probability of 0....
*November 16, 2012*

**math**

Assuming boy and girl babies are equally likely, find the probability that it would take a) at least three births to obtain two girls b) at least four births to obtain two girls c) at least five births to obtain two girls
*November 16, 2012*

**math**

Three men and three women are waiting to be interviewed for jobs. If they are all selected in random order find the probability of each event. All the women will be interviewed first. No man will be interviewed until at least two women have been interviewed
*November 16, 2012*

**math**

Assuming boy and girl babies are equally likely, find the probability that it would take a) at least three births to obtain two girls b) at least four births to obtain two girls c) at least five births to obtain two girls
*November 15, 2012*

**math**

Three men and three women are waiting to be interviewed for jobs. If they are all selected in random order find the probability of each event. All the women will be interviewed first. No man will be interviewed until at least two women have been interviewed.
*November 15, 2012*

**math**

One problem encountered by developers of the space shuttle program is air pollution in the area surronding the launch site. Acertain direction from the launch site is considered critical in terms of hydrogen chloride pollution from the exhaust cloud. It has been determined ...
*November 15, 2012*

**math**

Therese Felser manages a grocery warehouse which encourages volume shopping on the part of its customers. Therese has discovered that, on any given weekday 70 percent of the customer sales amount to more than $ 100. That is any given sale on such a day has a probability of 0....
*November 15, 2012*

**math**

if only digits 0,1,2,3,4,5,6, and 7 may be used find number of possibilites four digit numbers
*November 14, 2012*

**math**

given the digits 0,1,2,3,4,5,6, and 7 find the number of possibilities in each category four digit numbers, odd three digit numbers and three digit numbers without repeating digits.
*November 14, 2012*

**Physics Resistance**

this didnt seem to work. do the voltmeter and resistor have to be treated as a parallel connection?
*November 11, 2012*

**Physics Resistance**

A 65 V. battery is connected across a 65400 ohm and a 37700 ohm resistor connected in series. What is the per cent error in the voltmeter reading when placed across the first resistor, if the voltmeter resistance is 143000 ohms? Not sure where to go with this problem, Its easy...
*November 11, 2012*

**MAT 116**

oh drats non-linear is so much more fun! where x is length and y is width. 2x + 2y = 28 x - 10 = y solve with substitution
*November 11, 2012*

**Its math, cmon answer!!!**

cmon its 2
*November 11, 2012*

**Physics RC**

A 6.44 E+06 ohm resistor and a 1.00 microfarad capacitor are connected in a single loop circuit with a seat of emf of E = 2.00 V. At 6.00 s. after the connection is made, what is the rate at which energy (in joules/second) is being delivered by the seat of emf?
*November 11, 2012*

**Physics**

A 6.44 E+06 ohm resistor and a 1.00 microfarad capacitor are connected in a single loop circuit with a seat of emf of E = 2.00 V. At 6.00 s. after the connection is made, what is the rate at which energy (in joules/second) is being delivered by the seat of emf?
*November 10, 2012*

**physics**

Here's my attempt. V = 324.8 m^3 Total Energy of Students: 395280 J (in 54min) mass = 406kg q=mc(deltaT) q= 395280J c= 840 J/kg C m= 406 kg delta T = 1.16 C Tf = 20.0 C
*November 10, 2012*

**chemistry**

its C your original answer
*November 10, 2012*

**chemistry**

indeed
*November 10, 2012*

**chemistry**

Think a little more.. you have 1.25e23 atoms, and there are 6.02e23 atom in one mole. dividing the first by the second yields 2.08e-1 mol Mg
*November 10, 2012*

**Physics**

ive previously tried this and obtained 3.34e-13 m/s which the computer says is wrong where N = 8.46e28 m^-3 e = 1.6e-19 C and A = 7.07e-8 m^2
*November 10, 2012*

**Physics**

A small but measurable current of 3.20 E-10 A. exists in a copper wire whose diameter is 0.03 cm. Calculate the electron drift speed (in meters/second).
*November 10, 2012*

**chemistry**

you think correctly
*November 10, 2012*

**math**

denominator is the number beneath the line of a fraction. e.g. x/4 we know that 1/4 wont work, neither will 2/4 (1/2) nor 4/4 (1). That leaves us with one option 3/4 3/4 is greater than 1/2 but less than 1 and has a 4 in the denominator Hope that helps!
*November 10, 2012*

**chemistry**

you have the correct answer and are looking for an explanation? there are three nitrates of formula NO3. since there are 3 oxygen atoms per nitrate, and 3 nitrates total. 3x3 = 9 oxygen atoms per nitroglycerin
*November 10, 2012*

**biology**

d = m/v v = 5.18^3 m = 197g d = 197/(5.18^3) answer is in g/cm^3
*November 10, 2012*

**nuclear chemistry**

E=mc^2 10^6 J/s are being produced (1Mw) 10^6 J/s = m (3.0e8 m/s) solve for mass to find amount of mass lost in one second. ~ .0033kg
*November 10, 2012*

**Physics deflection ammeter**

thank you bob!
*November 10, 2012*

**Physics deflection ammeter**

8. A galvanometer has a coil resistance of 100 ohms and gives a full scale deflection when the potential difference across it is 0.0002 V. What size resistor (with a value measured in ohms) is required to make a 1.0 A. full scale deflection ammeter?
*November 10, 2012*

**Capacitor**

A parallel plate capacitor with plates of area 320 cm.^2 is charged to a potential difference V and is then disconnected from the voltage source. When the plates are moved 0.3 cm. farther apart, the voltage between the plates is increased by 152 V. What is the charge on the ...
*November 4, 2012*

**Capacitance **

A parallel plate capacitor with plates of area 320 cm.^2 is charged to a potential difference V and is then disconnected from the voltage source. When the plates are moved 0.3 cm. farther apart, the voltage between the plates is increased by 152 V. What is the charge on the ...
*November 3, 2012*

**Chemistry**

Tiffany, Assuming the reaction runs to completion and there is an excess of Al you know that Bromine is your limiting reagent. Stoichiometry will give you the amount of AlBr2 produced. You begin with 7.9 mol Br2 to cancel the moles of Bromine and find moles of Aluminum Bromide...
*November 3, 2012*

**Capacitance (tricky)**

Thanks! Our textbook did not cover dielectrics very well.
*November 3, 2012*

**Capacitance (tricky)**

Two parallel plates of area 41 cm.^2 have equal but opposite charges of 2.60E-07 C. Within the dielectric material filling the space between the plates, the electric field is 5.80E+05 V./m. Find the dielectric constant of the material. Feel like there is a huge lack of ...
*November 3, 2012*

**physics**

Alyssa, I suggest you draw a freebody diagram of the wagon and the handle. Youll notice that the handle has a force of magnitude 20N with a direction of 25 degrees above the horizontal. Now write your force summation using Newton's second law. Let Ft be the magnitude of ...
*November 3, 2012*

**John Jay**

what is sum or defference of 3/8 + 3/5
*October 26, 2012*

**calculus**

(a) Find the number c such that the limit below exists. Limit as x goes to -2 of: x^2+cx=c-3/x^2+2x (b) Calculate the limit for the value of c in part (a).
*October 24, 2012*

**math**

2 half dollars, 4 quarters, 2 dimes and 1 penny .50+.50+.25+.25+.25+.25+.10+.10+.01=2.21 2+4+2+1=9
*October 24, 2012*

**Math**

(a) Find the number c such that the limit below exists. Limit as x goes to -2 of: x^2+cx=c-3/x^2+2x (b) Calculate the limit for the value of c in part (a).
*October 24, 2012*

**Physics Conducting Spheres **

1. Two concentric conducting spherical shells have radii of 0.145 m. and 0.215 m. The inner sphere bears a charge of -3.00E-08 C. An electron escapes from the inner sphere with negligible speed. Assuming that the region between the spheres is a vacuum, compute the speed (in ...
*October 21, 2012*

**physics**

c)what is the balls speed just after the bounce?
*October 11, 2012*

**physics**

You drop a ball from a height of 1.9m , and it bounces back to a height of 1.3m . a)What fraction of its initial energy is lost during the bounce? b)What is the ball's speed just before the bounce?
*October 11, 2012*

**Physics**

Standing on a balcony, you throw your keys to a friend standing on the ground below. 1.2 seconds after you release the keys, they have an instantaneous velocity of 15.7 m/s, directed 52° below the horizontal. What initial velocity did you give them?
*September 20, 2012*

**Physics**

Standing on a balcony, you throw your keys to a friend standing on the ground below. 1.2 seconds after you release the keys, they have an instantaneous velocity of 15.7 m/s, directed 52° below the horizontal. What initial velocity did you give them?
*September 20, 2012*

**Physics**

What is the speed of the rocket when it is 350 above the surface of the earth? A rocket starts from rest and moves upward from the surface of the earth. For the first 10 of its motion, the vertical acceleration of the rocket is given by a(y)=2.9, where the -direction y+ is ...
*September 9, 2012*

**Physics **

A 160lb person steps into an elevator and stands on a bathroom scale. what is the weight on the scale when the elevator accelerates upwards at 2ft/s^2
*August 26, 2012*

**chemistry**

The average human body has 1.4x10^2 g of total K within it. Calculate the activity in disintegration/year of the potassium-40 in the average human body using your value of t1/2 (or K) of this substance
*August 22, 2012*

**calculus**

f(x)=[lnx]^5
*July 19, 2012*

**physics, please help me, this question is hard**

John Stands at the edge of a flat roof of a three story building and throws a 180g ball straight up into the air that reaches a height of 3.0 meters above the roof. ( building is 14 meters high) A. What is the initial speed of the ball? B. How long does it take to reach it'...
*July 5, 2012*

**help please :)**

yeah write teacher you are extremely rude get some manners
*June 19, 2012*

**Chemistry**

For 105ml of a buffer that is .40 M in HOCL and .36M in NaOCL what is the pH after 13.4 ml of 1.5M NaOH is added? Ka for HOCL is 3.5x10^-8
*June 12, 2012*

**Chemistry**

Alright, I got it thanks!
*June 4, 2012*

**Chemistry**

I'm messing up somewhere 1x10^30= [.011-x]/[x][.836+4x]^4 4.8x10^29(x)+2.56x10^32(x^5)=.011-x Factoring out an x and moving all terms x(4.8x10^29+2.56x10^32(x^4))-.011+x=0 Then because of the relative size I assumed -.011 and x are negligible x(4.8x10^29+2.56x10^32(x^4))=0...
*June 4, 2012*

**Chemistry**

What is the concentration of Hg^2+ in 500.0 mL of a solution that was originally 0.011 M Hg^2+ and had 73 g of KI added to it? Hg^2+(aq) + 4I^-(aq)<=> HgI4^2-(aq) The overall formation constant is 1x10^30
*June 4, 2012*

**physics**

A building has become accidentally contaminated with radioactivity. The longest-lived material in the building is strontium-90. (The atomic mass of Sr is 89.9077 u.) If the building initially contained 4.8 kg of this substance and the safe level is less than 10.0 counts/min, ...
*June 3, 2012*

**physics**

After 1.84 days, the activity of a sample of an unknown type radioactive material has decreased to 85.8% of the initial activity. What is the half-life of this material? (in days)
*June 3, 2012*

**Chemistry**

Alright, I was able to figure them all out. Thank you!
*June 1, 2012*

**Chemistry**

So for the first portion I came to Kb=1.5x10^-10 then x^2/.14-x= 1.56x10^-10 x^2-(2.2x10^-11)x - 1.56x10^-10=0 solving with the quadratic equation I came to x= 1.25x10^-5 (I'm disregarding i) So -log(1.25x10^-5)= 4.9 But somewhere I've done something wrong as the ...
*June 1, 2012*

**Chemistry**

Calculate the pH at the halfway point and at the equivalence point for each of the following titrations. (a) 100.0 mL of 0.14 M HC7H5O2 (Ka= 6.4 multiplied by 10-5) titrated by 0.14 M NaOH halfway point equivalence point (b) 100.0 mL of 0.29 M C2H5NH2 (Kb = 5.6 multiplied by ...
*June 1, 2012*

**science**

Its C...Nodules of certain plants such as clover fix Nitrogen to the soil...thats the reason farmers grow cver ...then plow it back into the soil..Natural source of Nitrogen...dontknow about the others...
*May 31, 2012*

**Introduction to Psychology**

way too much time on phone...in the shower..and on Facebook..:)
*May 31, 2012*

**Math**

Add it up...here goes..6 X $9.80...plus 1/4 hour =15 mins...so work out 1/4 of $9.80...remember 1/4 = 25%....then 7 x $14.50...plus 30 mins at $14.50/hr...remember 30 mins is 1/2 an hour so whats $14.50 divided by two..?...now add it all up and theres you answer...!
*May 31, 2012*

**Art**

Spanish Romanticism...not sure about any other....its oil on canvas (1820)
*May 30, 2012*

**math**

11,,,,,,!!!!
*May 29, 2012*

**math**

3y-12=21
*May 29, 2012*

**math**

It says Complete 10/3 on maths homework...what does this mean...thanks.. :)
*May 29, 2012*

**chemistry**

Its c....K= potassium...and there is is only one mentioned...and Cl= chlorine...again only one mentioned.. So its C...look up your elements table and it will tell you what K..is etc...then you wont have to send as many questions in...!!
*May 28, 2012*

**chemistry**

Its D..!!...the 2 after the Br means its attached to that element..so read as 2 X Br....there is nothing after the Mg...so that means there ais only one So therefore its D...
*May 28, 2012*

**Minoxidil**

C9H15N2O...chemical formula
*May 28, 2012*

**Minoxidil**

Try under its more common name "Rogaine"...its basically a chemical that slows hair loss....
*May 28, 2012*

**Religion**

Its Islam = Peace
*May 28, 2012*

**Physics**

A convex lens forms a real image 6 times the size of the object. The distance between object and image is 33 cm. Find the focal length of the lens.
*May 28, 2012*

**physics**

An object is placed 75.0 cm from a screen. (a)Where should a converging lens of focal length 8.0 cm be placed to form an image on the screen? shorter distance __cm from the screen farther distance __cm from the screen (b)Find the magnification of the lens. magnification if ...
*May 23, 2012*

**Chemistry**

Find [H+] [OH-] and Ph
*May 21, 2012*

**Chemistry**

A solution is prepared by adding 47.3 mL of concentrated hydrochloric acid and 16.3 mL of concentrated nitric acid to 300 mL of water. More water is added until the final volume is 1.00 L. Calculate [H+], [OH -], and the pH for this solution. [Hint: Concentrated HCl is 38% HCl...
*May 21, 2012*

**physics**

Calculate the magnitude and direction of the Coulomb force on each of the three charges connected in series: 1st - 6 micro Coulombs (positive charge) 2nd - 1.5 micro Coulombs (positive charge) 3dr - 2 micro Coulombs (negative charge) Distance between 1st and 2nd - 3cm Distance...
*May 21, 2012*

**physics**

An object is placed 75.0 cm from a screen. a)Where should a converging lens of focal length 8.0 cm be placed to form an image on the screen? shorter distance __cm from the screen farther distance __cm from the screen b)Find the magnification of the lens. magnification if ...
*May 21, 2012*

**physics**

A wire of initial length L0 and radius r0 has a measured resistance of 2.5 . The wire is drawn under tensile stress to a new uniform radius of r = 0.45r0. What is the new resistance of the wire?
*May 21, 2012*

**physics**

An air-filled capacitor consists of two parallel plates, each with an area of 7.60 cm2, separated by a distance of 1.70 mm. If a 19.2-V potential difference is applied to these plates, calculate the following: (a) the electric field between the plates, magnitude (in kV/m) and ...
*May 18, 2012*

**physics**

The potential difference between the accelerating plates of a TV set is about 30 kV. If the distance between the plates is 1.1 cm, find the magnitude of the uniform electric field in the region between the plates. (in N/C)
*May 17, 2012*

**physics**

Calculate the magnitude and direction of the Coulomb force on each of the three charges connected in series: 1st - 6 micro Coulombs (positive charge) 2nd - 1.5 micro Coulombs (positive charge) 3dr - 2 micro Coulombs (negative charge) Distance between 1st and 2nd - 3cm Distance...
*May 16, 2012*

**Chemistry **

Consider the following reaction: 2NOCl(g) 2NO(g) + Cl2(g) Initially pure NOCl(g) is placed in a vessel at 3.00 atm. At equilibrium, 0.416% of the NOCl has decomposed. Determine the value for Kp.
*May 13, 2012*

**Chemistry**

For the reaction below, Kp = 1.16 at 800.°C. CaCO3(s) CaO(s) + CO2(g) If a 25.0-g sample of CaCO3 is put into a 10.2-L container and heated to 800.°C, what percent of the CaCO3 will react to reach equilibrium?
*May 12, 2012*

**Science**

Table salt has a solubility of 36 g of salt in 100 g of water at 40°C. If 15 g of the salt are added to 50 g of water at the same temperature, is the resulting solution saturated or unsaturated? Explain your answer
*May 11, 2012*

**Math**

The question asks the opposite... not yellow. so 9/12 * 10/15 = .75 * .666 = 50%
*May 9, 2012*

**Physics**

calculate change in the momentum. remember that after it experiences this "perfectly elastic collision" it has a negative velocity. Therefore the change in momentum would be p = abs|m1v1 + m2v2| change in momentum p = Ft Force would be the average force or in this ...
*May 9, 2012*

**Chemistry**

solve q initial for the 240g of coke/water. solve q initial for the ice. subract q ice from q coke, then solve for deltaT q(coke) - q(ice) = (4.18 J/gK)(285g)(deltaT)
*May 9, 2012*

**?**

brought
*May 8, 2012*

**chemistry**

4Na + 02 = 2Na2O Considering Na is the limiting reagent.. 1.15g Na x 1molNa/23g x 2molNa2O/4molNa x 1molNa2O/62g = grams of Na2O
*May 8, 2012*

**Environmental Chemistry**

This is a strong acid/base titration. Balance your equation for the reaction and calculate if you have excess H30+ or OH- Remember that pH=-log[H30+] and pOH = -log[OH-] pOH = 14 - pH Where [H30+] and [OH-] is the concentration of each substance in moles/liter
*May 8, 2012*

**physics**

0 J
*May 7, 2012*

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