Friday

November 28, 2014

November 28, 2014

Total # Posts: 316

**probability**

The lifetimes of batteries are independent exponential random variables, each having parameter λ. A flashlight needs 4 batteries to work. If one has a flashlight and a stockpile of n batteries, what is the expected time that the flashlight can operate?
*November 22, 2014*

**Math **

Sally has 3 planting boxes . Each box is 4 feet wide and 8 feet long. How much space does she have altogether? Is it 3x4 + 3x8= 36 total feet?
*November 12, 2014*

**math**

LEGO R bricks are very common toys and have a structure that allows them to be placed on a rectangular grid. This makes them great for interesting questions about math. A 24 brick has two rows and four columns, making it have 8 total studs. But a 24 is the same as a 4...
*November 10, 2014*

**Physics **

Repairing a spaceship CJ drops a hammer and it took .68 s to fall .90 m to the ground. What is the magnitude of the gravitational accerleration on mars
*November 2, 2014*

**Calculus - PLEASE HELP!**

Find al points where tangent lines to: (x^2+y^2)^(3/2) = sqrt(x^2+y^2) + x is either horizontal or vertical using implicit differentiation.
*October 27, 2014*

**Calculus**

Find al points where tangent lines to: (x^2+y^2)^(3/2) = sqrt(x^2+y^2) + x is either horizontal or vertical.
*October 26, 2014*

**Calculus**

Find al points where tangent lines to: (x^2+y^2)^(3/2) = sqrt(x^2+y^2) + x is either horizontal or vertical.
*October 26, 2014*

**Calculus**

All right! Thank you :)
*October 26, 2014*

**Calculus**

a hyperbola passing through (8,6) consists of all points whose distance from the origin is a constant more than its distance from the point (5,2). find the slope of the tangent line to the hyperbola at (8,6).
*October 26, 2014*

**Calculus**

The graph of the equation x2 − xy + y2 = 9 is an ellipse. Find the lines tangent to this curve at the two points where it intersects the x-axis. Show that these lines are parallel.
*October 26, 2014*

**math**

A hotel has rooms numbered 1 to 1000. One thousand visitors enter the hotel. 1. The first visitor switches on the light switches of every room. 2. The second visitor switches off the light switches of every other room, starting with room 2. 3. The third visitor toggles the ...
*October 20, 2014*

**math**

yes,disregard the disclaimer....
*October 19, 2014*

**math**

Downtown Mathville is laid out as a square grid of 9 North-South streets and 9 East-West streets (See diagram). Your apartment is located at the Southwest corner of downtown Mathville. (See point T.) Your math classroom is located in a building that is 6 blocks East and five ...
*October 19, 2014*

**Math**

A number and its absolute value are equal. If you subtract 2 from the number, the new number and its absolute value are not equal. What do you know about this number? What is a possible number that satisfies these conditions?
*October 12, 2014*

**math**

Consider an equilateral triangle with points located at each vertex and at each midpoint of a side. (See picture.) This problem uses the set of numbers {1, 2, 3, 4, 5, 6}. Place one number at each point. Call the sum of the three numbers along any one side (two vertices and ...
*October 10, 2014*

**art history**

d.
*October 9, 2014*

**Science**

-Describe the zero sum rule -True of False: The formula for the nitride ion is N^(-3) -True of False: The stock system shows the charge on the negative ion Answer this Question
*October 1, 2014*

**math**

1. Finding the Counterfeit Coin. You have 5 coins. You know that one of them is counterfeit and weighs less than the others. Suppose also that you have a balance scale. Is there a strategy for finding the counterfeit coin using the balance scale only twice? If yes, what is the...
*September 30, 2014*

**chemistry**

A mixture of 3.00 g of silver and copper metals was dissolved in excess nitric acid. Resulting salts, silver(I) nitrate and copper(II) nitrate, were isolated and dissolved in enough water to make 0.100 L of a solution with a total concentration of the nitrate ion equal to 0....
*September 29, 2014*

**math**

Ruth buys 20 pencils for $20. some cost $4,some $0.25 and some $.50 each. at least one of each. How many of each price?
*September 22, 2014*

**physics**

7.4 waves crash onto a beach every 58.3 s. What is their frequency?
*September 21, 2014*

**Chemistry**

A protein subunit from an enzyme is part of a research study and needs to be characterized. A total of 0.135g of this subunit was dissolved in enough water to produce 2.00 mL of solution. At 28 ∘C the osmotic pressure produced by the solution was 0.138 atm. What is the ...
*June 27, 2014*

**Math**

√(5y+1)-√(3y-5)=2, I need to solve algebraically, and state any restrictions on the values for the variables, which I can't remember how to do
*June 12, 2014*

**MAth **

4+sqrt(4+x^2)=x, I need to isolate the x variable in the radical equation, but I can't figure out how to do it. The answer is x=3/2
*June 12, 2014*

**English**

Then it would be something along the lines of because 20% of teenagers and youth suffer from mental illnesses, parents should be aware of how to recognise problems in their children so they can receive proper care.
*June 11, 2014*

**English**

Because I don't know what a thesis statement is and I've never written one.
*June 11, 2014*

**English**

I've written the paper and edited it already.
*June 11, 2014*

**English**

Its less of an essay and more of an article type thing
*June 11, 2014*

**English**

Im writing an essay in English about mental illnesses in teenagers and youth and i can't think of An appropriate title for it. I need some ideas of how to make on or some suggestions.
*June 11, 2014*

**English **

I asked a question earlier about creating a title for an article i wrote in English, the article being about school, and the pressure to achieve and the stress on students, and I can't figure out a good title, I've gotten some help from people and suggestions but I can...
*June 3, 2014*

**Math**

7+15=22 7-15=-8 the line has to be between 8 and 22 to work, otherwise it would be a straight line so it cannot be a, 5cm
*June 3, 2014*

**English**

I didnt mean homework, I meant more that school work and the pressure to achieve is a large stress
*June 3, 2014*

**English**

I'm writing an article for my english exam prep, and my main topic that i went off of was the relationship between school, homework and stress on teenagers (the exam prep topic is relationships) in the article I talk about how homework is a large stress in most teenagers ...
*June 3, 2014*

**History**

Would an answer the question make sense if it was something like 'the ethical dimensions of bill 94 are that the bill is to protect the security of many people, but the ban on face coverings goes against peoples religion'
*June 3, 2014*

**History **

I still need help with what ethical dimensions are, I understand that it's 'the scope of right and wrong''the extreme of right and wrong' but I don't understand how to apply that to my question, which is what are the ethical dimensions of bill 94? Bill ...
*June 3, 2014*

**history **

What are ethical dimensions? I've searched google but I don't understand what it means.
*June 2, 2014*

**History **

What are the ethical dimensions of bill 94? (Bill in Quebec that banned face covering in any government funded building such as hospitals, government-subsidized high schools and universities) I mostly need help on the definition of ethical dimensions, I can't remember what...
*June 2, 2014*

**Math**

Kelly's scores on the first three tests in her physics class are 79, 84, and 68. Determine all scores on the fourth test that will yield an average test score of at least 80.
*May 24, 2014*

**History **

1)How did enlistment in the Canadian military change between first world war and second world war? What changed? I have a few points but I can't think of any more 2)how has the Canadian military changed from the second world war? Research the the inclusion policies to see ...
*May 23, 2014*

**History.**

Do you think the CRTC's restriction on media freedom were reasonable in the 1960's? DO you think they are reasonable now? Explain.
*May 15, 2014*

**Chemistry **

During an acid-base titration, 25 mL of NaOH 0.2 M were required to neutralize 20 mL of HCl. Calculate the pH of the solution for each: a) Before titration b) After adding 24.9 mL of NaOH c) At equivalence pt d) After adding 25. 1 mL of NaOH e) The pH of the equivalence pt ...
*May 10, 2014*

**Algebra 1B**

It's not factorable. Try using the quadratic formula to solve for x.
*May 10, 2014*

**physics**

A 50kg girl sits at the top of a slide 6m long tilted at an angle of 30 degrees. if it takes her 3.3s to slide to the bottom and the coefficient of kinetic friction is 0.45, how fast will she be going at the bottom?
*April 10, 2014*

**physics**

A car has a flywheel ( a diks of R=0.2m and uniformly distributed mass M=100kg) that can convert 25% of the rotational kinetic energy into translational kinetic energy. The mass of the car is 1000kg ( including flywheel). Suppose the car is at rest, and the flywheel has a ...
*December 30, 2013*

**physics**

Hi, Elena. Thanks for helping me with the neutron star problem. I knew the formula, but kept getting answers that were not close to the possible choices. What variables did you use. Thanks again for your help.
*December 25, 2013*

**physics**

Assume that the mass of a neutron star is 1.5 times that of the Sun and the radius of the neutron star is 10 km. Ignore effects of Special Relativity. What is the approximate speed at which an object released from far away (at zero speed) reaches the surface of a neutron star...
*December 25, 2013*

**PHYSICS URGENT HELP **

a charges electric potential energy within an electric field is calculated as the product of the ____ of it's position times the magnitude of it's charge
*December 18, 2013*

**Physics**

ANY ANSWERS WILL HELP! THANKS! 1. Isolated points of electric charge are called ____. 4b. ____ was the American physicist who first measured this fundamental unit of charge. 5. This type of electrification occurs when the charging rod touches an electroscope. 6. This type of ...
*December 17, 2013*

**chemistry**

determine the density in copper at 1305K. 1 mole of vacancies in copper is 104kJ. The answer I calculated this time is 8.4572*10^22. I am not sure if this correct. Thanks.
*November 17, 2013*

**chemistry**

DDD I may not be using the right formula. I am getting negative answers. Down to last chance.
*November 17, 2013*

**Chemistry**

I posted a question earlier today to determine the vacancy density in copper. The formation of 1 mole in Cu is 104kJ. Temperature is 1305K. My result is -2.19*10^-22. This does not look right to me. Any ideas. Thanks.
*November 17, 2013*

**chemistry**

I have been having a problem with solving a chemistry problem. The problem requires finding the density in copper at 1305K (the temperature changes when you reset the problem). I think I am using the proper formula, (N_v/N_s=Ae^-changeH_v/kT). My results are a very large ...
*November 17, 2013*

**chemistry**

I have been having a problem with solving a chemistry problem. The problem requires finding the density in copper at 1305K (the temperature changes when you reset the problem). I think I am using the proper formula, (N_v/N_s=Ae^-changeH_v/kT). My results are a very large ...
*November 17, 2013*

**biology**

Small gene big plasmid Question 2 Part E wrong. Question 2 Part F Determine the DNA sequence of PCR products. I do not understand how to handle this problem. On home works they were wrong and the solutions were confusing. Please give me a clue.
*November 16, 2013*

**chemistry**

N_v/N_s =Ae ^-change Hv/kT. What is the value of e^? Thanks.
*November 16, 2013*

**Physics **

6) The relationship between force and acceleration is given by Newton’s 2nd Law: Fnet = ma. In this case this becomes: Fapp...
*October 30, 2013*

**Chemistry**

Determine the sulfate ion concentrate in a solution prepared by diluting 15.00 ml of 0.115 M Y2(so4)3 with 35 ml of water?
*September 12, 2013*

**physics **

a baseball was launched from 1.5 m above the ground. the ball was caught at a position 4.5m above the ground with a speed of 28m/s moving at a angle of 30 degrees below horizontal: find initial velocity - time of flight - range
*September 10, 2013*

**physics **

a baseball was launched from 1.5 m above the ground. the ball was caught at a position 4.5m above the ground with a speed of 28m/s moving at a angle of 30 degrees below horizontal: find initial velocity - time of flight - range
*September 10, 2013*

**physics **

a baseball was launched from 1.5 m above the ground. the ball was caught at a position 4.5m above the ground with a speed of 28m/s moving at a angle of 30 degrees below horizontal: find initial velocity - time of flight - range
*September 10, 2013*

**english**

ask questions
*August 21, 2013*

**STATISTICS**

Should be C
*August 6, 2013*

**Physics**

When switched off, a spinning ceiling fan slows down with an angular acceleration of 1.2 rad/s2. If the fan was spinning at the rate of 10π rad/sec before it was turned off, how many revolutions did it go through before coming to the stop?
*June 30, 2013*

**Math**

There are 100 runners, each given a distinct bib labeled 1 to 100. What is the most number of runners that we could arrange in a circle, such that the product of the numbers on the bibs of any 2 neighboring runners, is less than 1000?
*June 24, 2013*

**Physics**

One of the proposed mechanisms for the lift of an aircraft is the pressure difference that develops due to the aerodynamic shape of the wings. Higher pressure develops bellow the airplane which lifts it up. Suppose you have a semi-circular wings with radius 1 m. If air ...
*June 24, 2013*

**MATH**

6+(4X7/14-1)=7
*June 24, 2013*

**Algebra**

Joe put 1/2 of his allowance into a savings. He spent 2/5 of the remainder on game rentals and 3.75 on snacks. How much is monthly allowance?
*June 12, 2013*

**chemistry**

this doesn't make sense
*May 23, 2013*

**Math**

If you have 1/2cup of water and you take out 3/8 of water how much do you have left
*May 1, 2013*

**math**

yes. there are a total of 10. thanks for the help
*April 11, 2013*

**math**

some years in the 20th century have 4 different odd digits. How many of those years have the sum of the digits greater than 20?
*April 11, 2013*

**Physics**

It seems wrong, please help!
*April 5, 2013*

**Physics**

Please help anyone!
*April 5, 2013*

**AP Chem**

MnS(s) + 2 H+ --> Mn2+ + H2S(g) At 25 C the solubility product constant, Ksp, for MnS is 5 x 10-15 and the acid dissociation constants K1 and K2 for H2S are 1 x 10-7 and 1 x 10-13, respectively. What is the equilibrium constant for the reaction represented by the equation ...
*January 13, 2013*

**physics**

A coin is placed on an old record turntable which rotates at 78 rpm. The coefficient of friction between the record and the coin is 0.17. b) At what distance (m) from the center will the coin begin to slide off the record? c) What is the period of the rotation (s) of the penny?
*January 4, 2013*

**physics**

A toy plane of mass 0.624 kg is flown in a circle when attached to a string. The plane moves around the circle with a rotational speed of 8.09 rpm. The length of the string is 2.60 m. What is the tension in the string?
*January 4, 2013*

**physics**

A student puts on a Dresden Dolls disc in her cd player which spins at 1800 revolutions per minute. A compact disc has a mass of about 0.016 kg and a radius of 6.0 cm. a) What is the period of rotation in seconds? b) What is the frequency of the rotating disc? d) What is the ...
*January 4, 2013*

**physics**

c) A penny sits 12 cm from the center of a record turning at 33 1/3 rpm. What is the tangential speed in m/s?
*January 4, 2013*

**physics**

On August 12, 2005 the Mars Reconnaissance Orbiter (MRO) was launched from Earth and reached Mars on March 10, 2006. The orbiter is in roughly circular orbit about 390 km above the martian surface. Mars has a radius of 3396 km and a mass of 0.642 x 1024 kg (6.42E23 kg). Here ...
*January 4, 2013*

**applied math**

At 1.25 per square foot what is tjh cost of cleaning a rug with dimension 9 ft.3 in.by 6feet 9 in,?
*November 26, 2012*

**math**

rewrite each expression using the distrubitive property 6x + (-5x)
*November 13, 2012*

**math**

I have 92 quarters, 46 dimes and 23 nickels in my jar. how money do i have
*November 1, 2012*

** 6th grade math**

what is 13/16 minus 1/4?
*September 4, 2012*

**History**

2. The 1978 Supreme Court decision in Bakke v. Regents of the University of California A. established the rights of students to appeal college admissions policies. B. established the "red state-blue state" divide. C. ruled in favor of...
*July 12, 2012*

**TRIG**

Given that tan¤=3/4 and ¤ is in the second quadrant find sin2¤ (¤=theta)
*July 11, 2012*

**TRIG**

Given that tan¤=3/4 and ¤ is in the second quadrant find sin2¤ (¤=theta)
*July 11, 2012*

**Physics**

A2.0-kg piece of steel with a temperature of 70 degree C is submerged in 1.0 kg of water at 15 degree C. At what temperature does the water/metal system reach equilibrium? The specific heat of steel is 0.107 cal/(g*K). Specific Heat of water is 4185 J/(kg*K.( The answer is 27 ...
*July 1, 2012*

**Physics**

7. A plastic cup, 15.0 cm in height, is filled to the rim with water. A small hole is punctured in the cup at a height 9.00 cm above the bottom of the cup and is allowing water to spew out. At what distance does the water land from the bottom of the cup?(Answer is 14.6 cm)
*July 1, 2012*

**Physics**

small cube of copper (density = 8930 kg/m3) is used to support a large cube of marble (density = 2560 kg/m3). The copper cube has sides of length 2.00 cm and is carefully placed on a flat, level table under the center of the cube of marble that has sides of length 30.0 cm. ...
*July 1, 2012*

**Physics**

Because the shape is symmetrical on the x axis you can say that the center of mass on the x is 6. To find center of mass on the y, all you have to do it break the shape into two smaller shapes, find the center of masses of those individual shapes, and then find the center of ...
*June 4, 2012*

**calculus**

lim_(theta->0)(cos(6 theta)tan(6 theta))/(theta)
*June 2, 2012*

**Algebra**

Thanks!
*May 27, 2012*

**Algebra**

The car traveling 100 mph states from a complete stop
*May 27, 2012*

**Algebra**

Leaves 2 minutes after the car at 80 mph passes it
*May 27, 2012*

**Algebra**

How long does it take a care traveling 100 mph to catch up to a car traveling 80 mph
*May 27, 2012*

**Math**

The price of a camera increased from $75 to $90 find the percent of the increase price
*May 9, 2012*

**Chemistry-Help**

The pressure of gas is measured at 550 mm Hg. How do you calculate this to Torr, lb/in2, atm, and in Hg? Please show conversions so that I can understand? Thank you!
*May 8, 2012*

**integral calculus**

a rectangular plate 12ft long and 8 ft wide is submerged vertically with the longer edge in the surface of the water. Find the force on one side of the plate.
*May 7, 2012*

** math**

Jon and Remy were in a car race. When Jon finished the race in 45min, Remy had only driven 2/3 of the distance. Remy's average speed for the race was 50m/min less than Jon's. a) Find the distance of the race. b) What was Remy's speed?
*April 30, 2012*