Wednesday
July 30, 2014

Posts by andrew


Total # Posts: 964

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

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?

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

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 t...

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

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 a...

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?

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 0.7...

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 0.7...

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 0.7...

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 0.7...

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

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

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

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.

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 tha...

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 0.7...

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

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.

Physics Resistance
this didnt seem to work. do the voltmeter and resistor have to be treated as a parallel connection?

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...

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

Its math, cmon answer!!!
cmon its 2

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?

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?

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

chemistry
its C your original answer

chemistry
indeed

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

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

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).

chemistry
you think correctly

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!

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

biology
d = m/v v = 5.18^3 m = 197g d = 197/(5.18^3) answer is in g/cm^3

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

Physics deflection ammeter
thank you bob!

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?

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 po...

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 po...

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...

Capacitance (tricky)
Thanks! Our textbook did not cover dielectrics very well.

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 informa...

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 fo...

John Jay
what is sum or defference of 3/8 + 3/5

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).

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

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).

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 me...

physics
c)what is the balls speed just after the bounce?

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?

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?

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?

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 upw...

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

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

calculus
f(x)=[lnx]^5

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'...

help please :)
yeah write teacher you are extremely rude get some manners

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

Chemistry
Alright, I got it thanks!

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...

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

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, h...

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)

Chemistry
Alright, I was able to figure them all out. Thank you!

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 homew...

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 1...

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...

Introduction to Psychology
way too much time on phone...in the shower..and on Facebook..:)

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...!

Art
Spanish Romanticism...not sure about any other....its oil on canvas (1820)

math
11,,,,,,!!!!

math
3y-12=21

math
It says Complete 10/3 on maths homework...what does this mean...thanks.. :)

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...!!

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...

Minoxidil
C9H15N2O...chemical formula

Minoxidil
Try under its more common name "Rogaine"...its basically a chemical that slows hair loss....

Religion
Its Islam = Peace

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.

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 pla...

Chemistry
Find [H+] [OH-] and Ph

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...

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...

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 place...

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?

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 ...

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)

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...

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.

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?

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

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

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 ca...

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)

?
brought

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

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

physics
0 J

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