Saturday

October 25, 2014

October 25, 2014

Total # Posts: 793

**Chem 2**

So i need to calculate the pH of 50ml water (de-ionized) with 1 ml of 1M HCl. So the moles of HCl i think is .001 divided by the total amount of solution (.051). I get 0.0196, then i take the negative log of this number and it comes out to 1.71 roughly. Does this sound right? ...
*October 14, 2013*

**Brief Calculus**

if s''(t)=((-)1/4t^3/2) +8 Then what is s''(16)?
*October 11, 2013*

**Brief Calculus**

The position s of a point (in feet) is given as a function of time t (in seconds). s = −10 + t − 15t2; t = 8 (a) Find the point's acceleration as a function of t. s''(t)= I know this answer, it is -30 (b) Find the point's acceleration at the ...
*October 10, 2013*

**Math**

Explain how you know whether an estimate of a product is an overestimate or an underestimate?
*October 10, 2013*

**pure maths, life science, physical science, geogra**

what can you study with those subjects
*October 10, 2013*

**General genetics**

I'm trying to find out how we know that bacteria involves contact before the transfer of DNA during conjugation. In the book, all they say is that DNA is not transferred along the f pilus as previously thought, but it is contacted first, then a channel opens up for the ...
*October 9, 2013*

**Brief Calculus**

Nevermind i figured it out. 30.1 years to maximize value
*October 8, 2013*

**Brief Calculus**

Last one for today... As the financial consultant to a classic auto dealership, you estimate that the total value (in dollars) of its collection of 1959 Chevrolets and Fords is given by the formula v = 303,000 + 1,020t2 (t ¡Ý 5) where t is the number of years from...
*October 8, 2013*

**Brief Calculus**

Minimize F = x2 + y2 with x + 2y = 5 Thank you
*October 8, 2013*

**physics**

yes to solve its the distance traveled/ 40(this is velocity) for acceleration its the velocity/5 so v=d/40 a=v/5
*October 5, 2013*

**physics (it's rather urgent help is appreciated**

@Anonymous how do you solve for the 7th question
*October 5, 2013*

**physics (it's rather urgent help is appreciated**

@ss01 if you check homework 2 the 2nd last question it shows you how to do question 2. for quetion 3 Ac must be 10m/s so you get 10=v^2/r and from there you can solve since i don't know what value of r you got
*October 5, 2013*

**physics (it's rather urgent help is appreciated**

which part?
*October 5, 2013*

**physics (it's rather urgent help is appreciated**

i got all except this one
*October 5, 2013*

**physics (it's rather urgent help is appreciated**

ss01 how do you solve this then
*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**

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**

physics
*October 5, 2013*

**URGENT**

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= 37 ∘. The gravitational acceleration is g=10 m/s2. (See figure...
*October 5, 2013*

**physics**

anon did you happen to solve the second last question? the one with the inclined roof
*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**

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*

**5th grade math**

I need to use quarters, dimes, nickles and pennies to make the following: $1.53 in 12 coins $2.53 in 20 $2.32 in 15 coins $2.00 in 22 $1.45 in 10 coins $1.76 in 16 coins $0.85 in 11 coins $1.01 in 12 coins $1.29 in 15 coins
*September 24, 2013*

**History**

8 is also wrong. Ghana is the first West African kingdom to benefit from the gold and salt trade because if you recall, between 400 and 1100, Ghana prospered because they were located in the middle of the salt mines of the Sahara and the gold mines of the south. In addition to...
*September 20, 2013*

**6th grade math**

look at 2 pounds as 6/3 pounds, (or 6 portions of 1/3 pound of beef.) Then you have an even number to compare with 6 cups. if you only need 1 cup, then you only need 1/3 pound of beef.
*September 17, 2013*

**Calculus**

f(x) = 4/5x i need to find the derivitave but i don't know how to start this one. I know the derivitave of 4 is just zero, and i know the derivative of 5x is 5. But the answer isn't 0/5. Help please.
*September 15, 2013*

**Math Homework HELP!**

Find the value of k so that the line containing the points (k,−8) and (−3,−5) is parallel to the line containing the points (9,7) and (12,5).
*September 14, 2013*

**algebra**

In 2010 a company reported a net income loss of 23.8 million. In 2011 the company reported a net income gain of 10.4 million. How much more income did the company earn in 2011 than in 2010
*September 4, 2013*

**Economics**

There are 1,000 hot dog stands in Chicago at any given moment. Due to health concerns, a significant number of families move out of the city. Would there be a shift in the demand curve, the supply curve, or both? I'm thinking that if this significant number moves out of ...
*August 13, 2013*

**math**

for a class trip a teacher brought 25 students tickets and 5 adult tickets: ~ write an expression for the total cost of tickets purchased ~if students tickets cost $4 each and adult tickets cost $6 each, how much money did the teacher spend on tickets?
*August 10, 2013*

**math**

order of operations 10) 2^4-3^2+5^2 11)32/(-7+5)^3 12)4^3-(2-5)^3
*August 10, 2013*

**math**

while riding her bike, jennifer burns 450 calories every 1/2 hour. Based on this rate, how many calories will jennifer burn if she rides her bike for 1 3/4 of an hour?
*August 10, 2013*

**physics**

A wind turbine is initially spinning at a constant angular speed. As the wind's strength gradually increases, the turbine experiences a constant angular acceleration 0.170 rad/s2. After making 2870 revolutions, its angular speed is 131 rad/s. (a) What is the initial ...
*July 16, 2013*

**Thermodynamics**

A lawnmower tractor engine produces 18hp using 40kW of heat transfer from burning fuel. Find the thermal efficiency and the rate of heat transfer rejected to the ambient. I converted the power to 13.24kW then found the efficiency by dividing 13.24kW by 40kW but the answer is ...
*June 12, 2013*

**Thermodynamics**

An empty cannister of 0.002 m3 is filled with R-134a from a line flowing saturated liquid R-134a at 0°C. The filling is done quickly so it is adiabatic, but after a while in storage, the can warms up to room temperature, 20degC. Find the final mass in the cannister and the...
*June 5, 2013*

**Chemistry DrBob222**

can you explain how to do t his i am confused
*May 29, 2013*

**Thermodynamics**

In a multiple-device flow system, I want to determine a state property. Where should I look for information, upstream or downstream?
*May 13, 2013*

**business calc**

The demand function for a certain brand of CD is given by p = −0.01x2 − 0.2x + 12 where p is the wholesale unit price in dollars and x is the quantity demanded each week, measured in units of a thousand. Determine the consumers' surplus if the market price is ...
*May 2, 2013*

**Thermodynamics**

Water in a piston/cylinder is at 100degC, x=0.5 with mass 1kg and the piston rests on two stops. The equilibrium pressure that will float the piston is 300 kPa. The water is heated to 300degC by an electrical heater. a) At what temperature would all the liquid be gone? I ...
*May 1, 2013*

**Enlish ARTS **

What is important as a last step in writing an essay?
*April 11, 2013*

**math**

a storage crate has the dimensions : 12ft * 6ft *5ft. how many cube-shaped boxes measuring 8 inches in length could be stacked completely within the cube??
*April 10, 2013*

**AP Stats (math)**

A large metropolitan area found that the time it takes for people to commute to work has a mean of 20.5 minutes and a standard deviation of 15.4 minutes. What is the probability that a random sample of 40 people have a mean commute time greater than 25 minutes?
*April 7, 2013*

**Chemistry**

The elements lithium and oxygen react explosively to from lithium oxide (Li2O). How much lithium oxide will form if 3.03 mol of lithium react? Answer in units of mol
*April 4, 2013*

**Chemistry**

At 103◦C, the pressure of a sample of nitrogen is 1.89 atm. What will the pressure be at 275◦C, assuming constant volume? Answer in units of atm
*April 4, 2013*

**Chemistry**

How many grams do 5.8×10 24 atoms of argon weigh? Answer in units of g
*April 4, 2013*

**chemistry**

t 103 ◦ C, the pressure of a sample of nitrogen is 1 . 89 atm. What will the pressure be at 275 ◦ C, assuming constant volume? Answer in units of atm
*April 4, 2013*

**Math**

Use intermediate value theorem to show there is a root to 2x^3 + x^2 - 2 = 0 on [0,1]
*March 13, 2013*

**Physics**

An aluminum ring of radius 5.00 cm and resistance 2.00 10-4 Ω is placed around the top of a long air-core solenoid with 997 turns per meter and a smaller radius of 3.00 cm, as in the figure below. If the current in the solenoid is increasing at a constant rate of 267 A/s...
*March 12, 2013*

**Math**

A box contains a one-dollar bill, a five-dollar bill, a ten-dollar bill, and a twenty-dollar bill. Two bills are chosen in succession without replacement. 1. What is the probability that the value of at least one of the bills is even? As a fraction
*February 13, 2013*

**Math**

Scott can travel from Rochester, N.Y., to New York City by bus, train, car, or airplane. He can travel from New York to London, England, by airplane or ship. 1. How many choices for the trip from Rochester to London are there?
*February 13, 2013*

**Math**

A box contains a one-dollar bill, a five-dollar bill, a ten-dollar bill, and a twenty-dollar bill. Two bills are chosen in succession without replacement. Use a tree diagram to list the sample space for this experiment and then answer the following questions in fractions 1. ...
*February 8, 2013*

**Probability **

A nickel is flipped and a dime is flipped. 1. What is the probability of obtaining exactly one head? A bag contains five balls numbered 0 through 4. Two balls are chosen at random in succession. The first ball is replaced before the second is chosen. 1. What is the probability...
*February 7, 2013*

**Math **

A nickel is flipped and a dime is flipped. 1. What is the probability of obtaining exactly one head? A bag contains five balls numbered 0 through 4. Two balls are chosen at random in succession. The first ball is replaced before the second is chosen. 1. What is the probability...
*February 7, 2013*

**Chemistry**

Calculate the radius of a vanadium atom, given that V has a BCC crystal structure, a density of 5.96 g/cm3, and an atomic weight of 50.9 g/mol. I used this equation: density = (2)*(atomic weight) / (volume of unit cell)*(Avagodro's #) rearranged to find the volume of the ...
*January 16, 2013*

**Chemistry**

Calculate the radius of a vanadium atom, given that V has a BCC crystal structure, a density of 5.96 g/cm3, and an atomic weight of 50.9 g/mol. I used this equation: density = (2)*(atomic weight) / (volume of unit cell)*(Avagodro's #) rearranged to find the volume of the ...
*January 16, 2013*

**Chemistry**

The atomic number of an electrically neutral atom is equal to the number of: Choose all that apply. Neutrons Electrons Protons I chose Electrons but somehow my homework program is telling me it's wrong? I also tried checking all of them.
*January 13, 2013*

**Calculus**

How do you simplify: 5*e^(-10x) - 3*e^(-20x) = 2 I'm not sure if I can take natural log of both sides to bring down the exponents.
*January 11, 2013*

**Calculus**

Hm, I've never done integrals using that method before. I'll check it.
*January 9, 2013*

**Calculus**

How do you integrate: 1/(x^2-1) dx ?
*January 9, 2013*

**math**

oh, its d! thanks so much
*December 30, 2012*

**math**

if -1/7x - 6 = 34, find the value of -2x + 3 a) -280 b) -77 c) 395 d) 563 Can you pls explain it for me too
*December 30, 2012*

**algebra 1**

please help. Write a linear equation in slope-intercept from to model the situation. A telephone company charges $28.75 per mont plus .10 cent a minute for long distance calls
*December 20, 2012*

**math**

solve each inequalitiy y+ (-5) > -6
*December 4, 2012*

**math pls help Ms Sue**

could you pls check my math 6< s +7 -1<s -8.7<y + (-12.4) 21.1<y x + 17 > 10 -7 > x 11 > j + (-19) 30>j 24.3 > g- (-14.4) 38.7> g f + (-20) > -7 f > 30
*December 3, 2012*

**Physics**

I dont know
*December 2, 2012*

**physics **

A bird is ﬂying with a speed of 19.0 m/s over water when it accidentally drops a 2.50 kg ﬁsh. The acceleration of gravity is 9.81 m/s^2 If the altitude of the bird is 9.00 m and air resistance is disregarded, what is the speed of the ﬁsh when it hits the ...
*November 28, 2012*

**math pls help Ms Sue**

Find the rule for the function table m n 15 12 10 8 5 4 0 0
*November 27, 2012*

**math**

Find the rule for each function table m n 15 12 10 8 5 4 0 0
*November 27, 2012*

**Physics. Error equations. Please help!**

These two equations concern a lab on the measurement of E/M by the Brainbridge Method. I need to derive the absolute error for two different equations, the first one is: e/m = 2V/B2R2 treat (e/m) as a SINGLE VARIABLE when doing the derivation. The second is B=8μ0N(I-Io...
*November 20, 2012*

**Physics**

In a very busy off-campus eatery one chef sends a 241-g broccoli-tomato-pickle-onion-mushroom pizza sliding down the counter from left to right at 1.53 m/s. Almost simultaneously, the other chef launches a 321-g veggieburger-on-a-bun (with everything, but hold the horseradish...
*November 19, 2012*

**Physics**

During a neighborhood baseball game in a vacant lot, a particularly wild hit sends a 148-g baseball crashing through the pane of a second-floor window in a nearby building. The ball strikes the glass at 10.1 m/s, shatters the glass as it passes through, and leaves the window ...
*November 19, 2012*

**Physics**

In a very busy off-campus eatery one chef sends a 241-g broccoli-tomato-pickle-onion-mushroom pizza sliding down the counter from left to right at 1.53 m/s. Almost simultaneously, the other chef launches a 321-g veggieburger-on-a-bun (with everything, but hold the horseradish...
*November 19, 2012*

**Physics**

An open train car, with a mass of 2150 kg, coasts along a horizontal track at the speed 2.29 m/s. The car passes under a loading chute and, as it does so, gravel falls vertically into it for 2.67 s at the rate of 441 kg/s. What is the car's speed after the loading is ...
*November 19, 2012*

**Physics**

A 70.0 kg football player leaps straight up into the air (with no horizontal velocity) to catch a pass. He catches the 0.430 kg ball precisely at the peak of his jump, when he is 19.2 inches off the ground. He hits the ground 1.61 inches away from where he leapt. If the ball ...
*November 19, 2012*

**Physics**

During a neighborhood baseball game in a vacant lot, a particularly wild hit sends a 148-g baseball crashing through the pane of a second-floor window in a nearby building. The ball strikes the glass at 10.1 m/s, shatters the glass as it passes through, and leaves the window ...
*November 19, 2012*

**Physics**

An unfortunate astronaut loses his grip during a spacewalk and finds himself floating away from the space station, carrying only a rope and a bag of tools. First he tries to throw a rope to his fellow astronaut, but the rope is too short. In a last ditch effort, the astronaut ...
*November 19, 2012*

**Physics. Please please help!**

Shouldn't the answer be 1.62*10^4V? Unless i'm putting the numbers in wrong. Please help
*November 14, 2012*

**Physics. Please please help!**

A charge Q = +4.5 uC is located at the origin and is fixed so that it cannot move. A small object with mass m = 2.0 g and charge q = +8.0 uC is released from rest at point A on the x-axis at x = 2.0 cm. The small object moves without friction along the x-axis under the ...
*November 14, 2012*

**calculus**

A five feet piece of wire is cut into two pieces. One Piece is bent into a square and the other is bent into an equilateral triangle. Where should the wire be cut so that the total area enclosed by both is minimum.
*November 14, 2012*

**Physics**

"You will measure the tension T, the mass m, and the length L of your spring. In terms of these variables, what is the expected frequency of the fundamental standing wave?" I found the fundamental frequency to be: f = 1/2L * sqrt(T/m/L)?
*October 31, 2012*

**Math**

write an algebraic expression then evaluate, given n=2 5 less than the quotient of -10 and a number is the answer (-10 / 2) - 5 = 0
*October 30, 2012*

**Physics**

"A slinky that satisfies v = sqrt(T/_mu) is stretched 12m. The mass of the slinky is 0.8kg. The tension on the slinky is 4N. What is the expected wave speed?" To get mu, I divided the mass by the length then plugged that into the equal and solved for v but I'm ...
*October 30, 2012*

**math**

260 divided by 10=26 does (260 divided by 10)x5=26x5
*October 29, 2012*

**calculus (math)**

Simplify exactly log_2 1/16
*October 27, 2012*

**math**

how could you use the product of 108 and 4 to find the product of 324 and 4?
*October 24, 2012*

**math**

an airplaine has an altitude of 20,000 feet. it climbs another 5,000 feet to avoid a storm. What integer expresses the position of the airplane compared to ground level?
*October 24, 2012*

**math**

-4 - (-8) = I got 4 is this correct -2 - (-6) = Again I got 4 is this also correct
*October 23, 2012*

**PHYSICS H**

suppose an elephant and a feather fall from a skyscraper. in the presence of air resistance, the elephant would fall faster because...list all that apply. a) acceleration of gravity is greatest for the elephant b) elephant experiences a smaller air resis. force c) the greater ...
*October 23, 2012*

**Physics**

Why is it necessary to collimate the light source before using the prism to disperse the light? A. If white light enters the prism with different angles, some of the blue light will exit the prism with the same angle as the orange light. B. If white light enters the prism with...
*October 22, 2012*

**math**

A spiiner was spun 16 times. The results are shown in the table below. yellow = 5 white = 4 red = 0 blue = 2 green = 2 orange = 3 whch colors' experimental probability matches its theoretical probability a. yellow, green and orange b. white, red and orange c. yellow, blue ...
*October 21, 2012*

**engineering**

A string is fit snugly around the circumference of a spherical hot air balloon. More hot air is added (probably by a prominent scientist’s lecture) and it now takes an additional 12.4 feet of string to fit around the circumference. What is the increase in diameter?
*October 17, 2012*

**Math. Have answer, please show work**

In a tracer method the potassium isotope 42K is used for labelling. The half life of 42K is 12.5 hours. If No is original number of atoms, how many hours will it take until only (1/1024) No Atoms remain? The answer is 125 hours but I do not know how to get this. Please help!
*October 13, 2012*

**math. solve for t**

im getting 104 hours but the correct answer is 125 hours?
*October 13, 2012*

**math. solve for t**

1/1024=42*0.5^(t/12.5) Solve for t. Please show work. Much appreciated!
*October 13, 2012*

**Math**

u-2√u=3. what is u?
*October 13, 2012*

**Chemistry**

The molar enthalpy of combustion of glucose is -2803 kJ. A mass of 1.000 g glucose is combusted in a bomb calorimeter. If the calorimeter contains 875 g H2O and the bomb has a heat capacity of 457 J/C, what is the temperature increase of the bomb calorimeter? the specific heat...
*October 11, 2012*

**Chemistry**

The molar enthalpy of combustion of glucose is -2803 kJ. A mass of 1.000 g glucose is combusted in a bomb calorimeter. If the calorimeter contains 875 g H2O and the bomb has a heat capacity of 457 J/C, what is the temperature increase of the bomb calorimeter? the specific heat...
*October 11, 2012*

**Chemistry**

The molar enthalpy of combustion of glucose is -2803 kJ. A mass of 1.000 g glucose is combusted in a bomb calorimeter. If the calorimeter contains 875 g H2O and the bomb has a heat capacity of 457 J/C, what is the temperature increase of the bomb calorimeter? the specific heat...
*October 11, 2012*

**logic**

The sentence "P → Q" is read as
*October 7, 2012*

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