Saturday

May 23, 2015

May 23, 2015

**physics**

A frictionless massless pulley has 7 kg tied to a cable on the left side and an unknown mass (M) on the right. The unknown mass accelerates downward at 6.6 m/s2 What is the accelerationof the system/tension of the rope
*Monday, October 13, 2014 at 5:12pm*

**Physics **

A particle of mass =6.50 kg moves with a velocity v1=x1i+y1j+z1k. A second particle of mass =3.50 kg moves with a velocity v2=x2i+y2j+z2k. And a third particle of mass =6.30 kg moves with a velocity v3=x3i+y3j+z3k. Here, (x1,y1,z1)=(-2.5,5.4,1.2), (x2,y2,z2)=(-2.3,0.1,-2.5) ...
*Monday, October 13, 2014 at 4:21pm*

**College Physics**

Two crates are connected by a massless rope that passes over a pulley. If the crates have mass 33 kg and 82 kg, find their acceleration. If the system begins at rest, with the more massive crate a distance 12 m above the floor, how long does it take for the more massive crate ...
*Monday, October 13, 2014 at 3:43pm*

**Math**

1) An aerobics class is being offered at the ABC body gym. Nonmembers pay $4 per class while member pay a monthly fee of $10 plus $2 per class. a. Create a linear system to represent the two options. b. At how many classes will the cost be the same? What is that cost? c. When ...
*Monday, October 13, 2014 at 11:26am*

**Math**

3) While traveling for vacation, you have decided to divide your lodging between a resort, and a regular stay hotel. Let x represent the number of nights you will spend in a resort, and let y represent the number of nights you will spend in a regular stay hotel. a. Write a ...
*Monday, October 13, 2014 at 2:08am*

**physics**

. What is the resultant momentum of a system of two particles with these masses and velocities: 3.75 kg moving north at 5.6 m/s and 4.2 kg moving northwest at 2.3 m/s?
*Sunday, October 12, 2014 at 8:59am*

**Algebra 2 Answer Check**

Classify each system and determine the number of solutions. {3y = 2x; -4x + 6y = 3 A: inconsistent; no solution
*Saturday, October 11, 2014 at 8:16pm*

**Biology**

What is the location and effect of waves of contraction in the digestive system.
*Saturday, October 11, 2014 at 8:05pm*

**Math College (Algebra)**

How to solve this system? x + [(3x-y)/(x^2+y^2)] = 3 y - [(x+3y)/(x^2+y^2)] = 0
*Saturday, October 11, 2014 at 7:19pm*

**Algebra 2**

solve each system of equation 3x+5y+2z=4 2x-2y+3z=-4 x+y+z=0 *could you show work because I want to learn how you got this answer
*Saturday, October 11, 2014 at 5:35pm*

**College Algebra**

How to solve this system? x + [(3x-y)/(x^2+y^2)] = 3 y - [(x+3y)/(x^2+y^2)] = 0
*Saturday, October 11, 2014 at 9:25am*

**Physics**

Block B in the figure(Figure 1) rests on a surface for which the static and kinetic coefficients of friction are 0.65 and 0.40, respectively. The ropes are massless.What is the maximum mass of block A for which the system is in equilibrium? (Consider the state of the system ...
*Friday, October 10, 2014 at 8:01pm*

**Physics**

Two masses, m1 = 25.0 kg and m2 = 45.0 kg, are attached by a massless rope over a massless pulley as shown above?The angle of the frictionless incline is 27.0 degrees . Assume that m2 starts at rest and falls a vertical distance of 3.00 m. Assume m1 also starts at rest and the...
*Friday, October 10, 2014 at 3:10am*

**Statistics**

Assume that the mean hourly cost to operate a commercial airplane follows the normal distribution with a mean of $2,325 per hour and a standard deviation of $240. What is the operating cost for the lowest 5 percent of the airplanes?
*Thursday, October 9, 2014 at 11:31pm*

**physics**

A 20 kg object is acted on by a conservative force given by F = -3.0 x - 5.0 x 2, with F in newtons and x in meters. Take the potential energy associated with the force to be zero when the object is at x = 0. (a) What is the potential energy of the system associated with the ...
*Thursday, October 9, 2014 at 11:23pm*

**physics**

Two people jump out of an airplane. They hold on to each other while falling straight down at a shared terminal speed of 60.7 m/s. Suddenly, they push away from each other. Immediately after separation, the first skydiver (who has a mass of 89.3 kg) has the following velocity ...
*Thursday, October 9, 2014 at 10:40pm*

**physics**

The pulley system in Figure 6-25 is used to lift a crate of mass m = 41 kg. Note that a chain connects the upper pulley to the ceiling and a second chain connects the lower pulley to the crate. Assume that the masses of the chains, pulleys, and ropes are negligible.
*Thursday, October 9, 2014 at 9:47pm*

**Algebra**

Graph the system below and write its solution. =3x+y−6 =y−1/2x-1
*Thursday, October 9, 2014 at 8:25pm*

**Algebra**

Graph the system below and write its solution. =+3xy−6 =y−−12x1
*Thursday, October 9, 2014 at 8:09pm*

**Physics **

A crate sets on wooden horizontal surface (a wooden floor). The figure shows a top view of this looking down onto the crate (gravity would be acting into the page). Man one and man two apply forces F1 and F2, at angles of θ1 and θ2 respectively, with the goal of ...
*Thursday, October 9, 2014 at 1:27pm*

**College Science **

A chandelier is suspended by two identical, vertical chains side by side. The chandelier's mass is m = 5.3 kg. A. If the tension in one chain is represented by T, write an expression for this tension in terms of m and g, the gravitational acceleration on the Earth's ...
*Thursday, October 9, 2014 at 1:17pm*

**@someone who can show me how to do this**

Hi I'm Aluminum<3 Helping and C.S.I, but you can call me Alumi. for short. So here's my Question,Determine how many solutions exist for the system of equations. I need someone who can WORK IT OUT with me and SHOW me how to do it. 1. 6x+y=−3 2. 6x+y=−3 ...
*Thursday, October 9, 2014 at 1:14pm*

**Physics**

In the system shown in the figure, suppose the block has a mass of 2.7kg , the spring has a force constant of 500N/m , and the coefficient of kinetic friction between the block and the floor is 0.18. Find the work done on the block by the spring and by friction as the block is...
*Thursday, October 9, 2014 at 11:07am*

**physics**

In the figure, a frictionless roller coaster car of mass m = 938 kg tops the first hill with speed v0 = 14.9 m/s at height h = 31.5 m. How much work does the gravitational force do on the car from that point to (a) point A, (b) point B, and (c) point C? If the gravitational ...
*Wednesday, October 8, 2014 at 7:17pm*

**government**

How do the three branches work within the system of checks and balances?
*Wednesday, October 8, 2014 at 5:52pm*

**Physics**

Two masses, m1 = 25.0 kg and m2 = 45.0 kg, are attached by a massless rope over a massless pulley. The angle of the frictionless incline is α = 27.00. Assume that m2 starts at rest and falls a vertical distance of 3.00 m. Assume m1 also starts at rest and the rope remains...
*Wednesday, October 8, 2014 at 4:23pm*

**Physics**

Assume that the batter did not continue to swing the bat after the collision (no energy was added to the system). How fast was the bat moving after the collision? The ball mass .145kg, the bats mass is 1.1kg. And the balls velocity is 44.7m/s and the bats velocity prior to ...
*Wednesday, October 8, 2014 at 1:13pm*

**algebra**

What is the solution to the linear system of equations? x + 4y = 8 x y = 7 (4, 3) (4, 3) (7, 0) The system has no solution.
*Wednesday, October 8, 2014 at 10:46am*

**social studies**

1.How were the farms of New England colonies similar to the farms of the up country? a. They grew rice b. They were plantations*** c. They had short growing seasons d. They were small subsistence farms 2.Rice grew successfully in south Carolina because slaves_____. a. Brought ...
*Tuesday, October 7, 2014 at 11:41pm*

**algebra 2**

Graph the system of constraints and find the value of x and y that maximize the objective function. Constraints {x >= 0 y >= 0 y <= 3 y <= -x+5} Objective Function C=-5x+3y a) 0,0 b) 2,3 c) 5,0 d) 0,3 I am a mom going crazy. I did horrible in math in school. ...
*Tuesday, October 7, 2014 at 10:07pm*

**Physics HELP**

Two blocks having mass m1 = 6 kg(m1 on ramp of 30 degrees) and m2 =3 kg are connected by a light rope and slide on a frictionless surface as in the figure below. A force F = 10 N acts on m2 at 20 degrees relative the horizontal. Find the acceleration of the system and the ...
*Tuesday, October 7, 2014 at 7:50pm*

**Intro Physics - Newton's third rule**

a piano mover raises a 1000 N piano at a constant speed using a very light rope in a frictionless pulley system. with what force is the mover pulling down on the rope? Show steps please! Thank you!
*Tuesday, October 7, 2014 at 5:45pm*

**Satistics**

Assume that the mean hourly cost to operate a commercial airplane follows the normal distribution with a mean of $2,175 per hour and a standard deviation of $175. What is the operating cost for the lowest 10 percent of the airplanes? (Round z value to 2 decimal places. Omit ...
*Tuesday, October 7, 2014 at 4:41pm*

**Social studies **

3.how were farms of the new england colonies similar to the farms of the up country A.separating church and state B.requiring all laws be approved by the council*** C. Creating a jury system for legal decisions D. Giving the people a stronger voice in the government
*Tuesday, October 7, 2014 at 9:59am*

**Wolrd History (Ms. Sue)**

This is the final post I will post about this. However, what do you think of this as a whole? Does my writing require any improvements? Does it flow smoothly? Do you agree with my statements? I may seem a little paranoid about this, but I'm not very skilled at writing ...
*Monday, October 6, 2014 at 5:05pm*

**Social Studies**

What was one thing that the Salzburgers established that the other settlers did not? A. Hospital B. School System C. trading post D. tavern I think C??
*Sunday, October 5, 2014 at 11:18am*

**statistics**

In a major city 7 % of cars have an alarm system installed. A car without an alarm has a probability of 0.01 of being stolen, this is triple the probability of a car with an alarm being stolen. What is the probability that a car stolen from this city has an alarm system ...
*Saturday, October 4, 2014 at 5:05pm*

**Pre-Calc**

The number of pounds of apples a cannery can produce and the processing cost are P(h) = 375h and C(n) = 0.35n + 1000 where P(h) is the number of pounds of apples that can be processed in h hours and C(n) is the cost of processing n pounds of apples. Use composition of ...
*Saturday, October 4, 2014 at 10:27am*

**Pre-Calc/Trig...**

Am i correct? It is possible for a system of linear equations to have no solutions. True <-- False i think it's true, if the lines are parallel?
*Friday, October 3, 2014 at 5:47pm*

**programing**

1. Elements – sequence-series outputting Write a program that prints the following elements: 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, (hereto referred to as elements) etc., up till a user-entered value. The program should not print more than 10 numbers per line. The last line ...
*Friday, October 3, 2014 at 3:47am*

**Chemistry **

What amount of energy is required to melt a 27.4 g piece of ice at 0oC? The heat of fusion of ice = 333 Jg-1 Heat required to melt the ice 9.12e3 = J What amount of energy must be removed from 123 g of water to cool it from 71.6oC to 9.41oC? Specific heat of water = 4.184 JK-...
*Thursday, October 2, 2014 at 9:28pm*

**statistics**

c. The arrival of large jobs at a computer centre forms a Poisson process with rate 2 per hour. The service time of such jobs are exponentially distributed with mean 20 minutes. Only 4 large jobs can be accommodated in the system at a time. i. Determine the probability that a ...
*Thursday, October 2, 2014 at 3:44pm*

**Science--3 questions? :c**

15. The___hypothesis suggests that our solar system evolved from a huge rotating cloud of dust and gas. 16. Lines of____are used to measure distances east or west of the prime meridian in degrees. 17. The major difference between a topographic map and other maps is that a ...
*Thursday, October 2, 2014 at 2:46pm*

**Business Computer Information Systems**

A large department store has been attaching tags with barcodes to merchandise, and employees use barcode readers to scan merchandise at the cash register. However, the wireless barcode readers need new batteries often. Also, using this system for inventory tracking is very ...
*Thursday, October 2, 2014 at 12:55pm*

**business computer Information Systems**

A large department store has been attaching tags with barcodes to merchandise, and employees use barcode readers to scan merchandise at the cash register. However, the wireless barcode readers need new batteries often. Also, using this system for inventory tracking is very ...
*Thursday, October 2, 2014 at 12:53pm*

**businessomputer Information Systems**

A large department store has been attaching tags with barcodes to merchandise, and employees use barcode readers to scan merchandise at the cash register. However, the wireless barcode readers need new batteries often. Also, using this system for inventory tracking is very ...
*Thursday, October 2, 2014 at 12:49pm*

**Int. science**

Which of the following is an example of a cycle theme in science? seasons electrons and protons the solar system relationship between plants and animals
*Thursday, October 2, 2014 at 10:37am*

**physics**

Object A is moving due east, while object B is moving due north. They collide and stick together in a completely inelastic collision. Momentum is conserved. Object A has a mass of mA = 16.7 kg and an initial velocity of nu Overscript bar EndScripts Subscript 0A = 8.32 m/s, due...
*Thursday, October 2, 2014 at 2:58am*

**algb**

Z the Intergalactic Candy Store for $1.75. Jeejuu paid $1.88 and got 4 xylobars and 1 yackity. How much Dado pay for 1 xylobar and 2 yackities?imak bought 3 xylobars and 5 yackities from .....Write a system of equations. Then solve the equations using the methods: substitution...
*Wednesday, October 1, 2014 at 6:04pm*

**Algebra **

Write a system of equations to match each of these problems. Then solve the equations using the method... Substitution, or linear combinations. 1. Maria started her savings account with $105. She adds $10 to it each month, including the first month. Jana Rae started her ...
*Wednesday, October 1, 2014 at 6:01pm*

**Math-G7 Help please**

Write a system of equations to match each of these problems. Then solve the equations using the method... Substitution, or linear combinations. _____________________________________ 1. Dan is 4 years older than his brother Gabriel. Together their ages equal 22. How old is ...
*Wednesday, October 1, 2014 at 5:57pm*

**E.L.A. PLEASE CHECK!**

Which choice best describes the underlined word or words in each sentence? The ancient Sumerians, Egyptians, and Chinese each developed a unique system of writing. Underlined is: Sumerians Egyptians Chinese A- simple subject B- compound subject C- complete subject D- none of ...
*Wednesday, October 1, 2014 at 5:24pm*

**chemistry**

a system consisting of 1.5 mol CO2(g), initially at 15deg and 10 atm and confined to a cylinder of cross-section 10.0 cm2. it is allowed to expand adibatically against an external pressure of 1.0 atm until the piston has moved through 20 cm. assume that carbon dioxide may be ...
*Wednesday, October 1, 2014 at 2:52pm*

**science**

1) Which of the following is a valid reason why a scientist might reject a scientific theory? (1point) Some people disagree with it. It covers too broad a topic. New evidence contradicts it.*** It is too old. 2) A scientific hypothesis must be (1point) Correct Able to be ...
*Wednesday, October 1, 2014 at 2:11pm*

**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
*Wednesday, October 1, 2014 at 10:01am*

**Chemistry **

-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
*Wednesday, October 1, 2014 at 1:14am*

**Math**

An electrician was hired to run the wires for a surround-sound stereo speaker system. She purchased 2 rolls of 14-gauge speaker wire. Each roll contains 4 m of wire. For each of 2 speakers, 2 ft. of wire are required. For each of the other 2 speakers, 11 ft. of wire are ...
*Wednesday, October 1, 2014 at 12:06am*

**Chemistry **

HELP PLEASE. I have no idea how to set this up. I tried using the q=mc(change in temp) equation but its not working out. A 59.8 g block of an unknown metal at 87.5 degrees Celsius was dropped into an insulated vesssel containing approximately 33 g of ice and 23 g of water at 0...
*Tuesday, September 30, 2014 at 7:00pm*

**Pre-Calculus/Trigonometry**

Solve the following system of equations algebraically. Verify the solution by using matrices. 8x-2y=5 -12x+3y=7
*Tuesday, September 30, 2014 at 1:23pm*

**Chemistry**

Chemistry question: Given: CH4 + 2O2 ~ CO2 + 2H2O C - H = 99 kcal O - O = 119 kcal C = O = 192 kcal O - H = 111 kcal Calculate the change in energy for the CH4 - O2 system.
*Tuesday, September 30, 2014 at 9:13am*

**physics**

This graph in the figure (Figure 1) shows how the temperature of an initially solid sample changes as time goes by when it is placed above a flame that delivers a constant heating power (that is, a fixed amount of energy input in the form of heat each second). The process ...
*Tuesday, September 30, 2014 at 3:34am*

**Pre-Calculus/Trigonometry**

Solve the following system of equations algebraically. Verify your solution by using matrices. 3x-y=0 5x+2y=22
*Monday, September 29, 2014 at 7:22pm*

**algebra2**

graph each system of equations and describe it as consistent and independent, consistent and depedneent, or inconsistent 40. x-6y=12 3x+18y=14 41. -5x-6y=13 12y+10x=-26 42. 8y-3x=15 -16y+6x=-30
*Monday, September 29, 2014 at 5:53pm*

**algebra 2**

graph each system of equations and describe it as consistent and independent, consistent and depedneent, or inconsistent 37. y=3x-4 y=6x-8 38. y=2x-1 y=2x+6 39. 2x+5y=10 -4x-10y=20
*Monday, September 29, 2014 at 5:50pm*

**algebra 2**

graph each system of equations and describe it as consistent and independent, consistent and dependent, or inconsistent 10. y+4x=12 3y=8-12x 11. -2x-3y=9 4x+6y=-18 12. 9x-2y=11 5x+4y=13
*Monday, September 29, 2014 at 5:46pm*

**Pre-Calculus/Trigonometry**

give an example of an arithmetic sequence also give an example of a system of equations with no solutions
*Monday, September 29, 2014 at 5:42pm*

**Statistics**

James has $78. He nees to buy some cds and tapes. He can buy 4 cds and 3 tapes and has $3 left or buy 3 cds and 5 tapes and has $13 left. Using system equation, find the cost of each.
*Monday, September 29, 2014 at 2:42pm*

**History**

How did the settlement of whites and their influence eventually affect the economy of the Five Tribes? A.Tribes learned new herding techniques and adopted US currency. B.Tribes traded in their villages rather than using trading posts. C.Tribes began to use a barter system to ...
*Monday, September 29, 2014 at 11:38am*

**physics**

One object is at rest and another is moving. The two collide in a one-dimensional, completely inelastic collision. In other words, they stick together and move off with shared velocity. The speed of the object that is moving initially is 25 m/s. The masses of the two objects ...
*Monday, September 29, 2014 at 12:58am*

**World History Answer Check**

1. What was the overall effect of Napoleon's Civil Code? A: The overall effect of Napoleon's Civil Code was to erode the remnants of the feudal system by further weakening the traditional power of the nobility and clergy. 2. Why did being a sea power help Britain to ...
*Sunday, September 28, 2014 at 11:02pm*

**Physics**

A force F acts to the right on a 4.81 kg block. A 2.53 kg block is stacked on top of the 4.81 kg block and can slide on it with a coefficient of friction of 0.2 between the blocks. The table has a coefficient of friction of 0.23. The acceleration of gravity is 9.8 m/s 2 . The ...
*Sunday, September 28, 2014 at 8:30pm*

**Physics **

A system absorbs 1000 Joules of heat and delivers 600 Joules of work, while loosing 100 Joules of heat by conduction to the atmosphere, the change in the internal energy of the system will be. My solution. I used U=Q+A, and my answer was 1600, but its real answer is 300 Joules...
*Sunday, September 28, 2014 at 4:59pm*

**Economics**

What happens to the cash flow statement for a company operating on a calendar year when a sale is made in December but the firm isn’t paid until the following January?
*Sunday, September 28, 2014 at 12:50pm*

**Material Sciences**

Given an aluminum shell perfectly bonded to a steel core, what is the thermal stress in the aluminum shell when the system is heated from the unstressed state (20∘C) to 180∘C? Consider only deformations in the axial directions. Give your answer in MPa αAl=23.6...
*Saturday, September 27, 2014 at 11:57pm*

**Accounting Please help me**

Bethany Link delivers parts for several local auto parts stores. She charges clients $0.75 per mile driven. She has determined that if she drives 2,100 miles in a month, her average operating cost is $0.55 per mile. If Bethany drives 4,200 miles in a month, her average ...
*Saturday, September 27, 2014 at 9:05pm*

**Pre-Calc**

Solve the system of equations using either the substitution method or the multiplication/addition method answer: 3x+2y=14 2x-4y=4
*Saturday, September 27, 2014 at 8:30pm*

**Business**

What happens to companies with high operating leverage when the market declines? What happens when the market expands?
*Saturday, September 27, 2014 at 7:36pm*

**Finance**

What happens to the cash flow statement for a company operating on a calendar year when a sale is made in December but the firm isn’t paid until the following January?
*Saturday, September 27, 2014 at 3:37pm*

**Finance**

1. What happens to companies with high operating leverage when the market declines? What happens when the market expands?
*Saturday, September 27, 2014 at 3:36pm*

**algebra 2**

Solve each system of equation by grpahing? 3. y=-3x+6 2y=10x-36 4. y=-x-9 3y=5x+5
*Saturday, September 27, 2014 at 12:55pm*

**math**

Identify the solution(s) of the system of equations, if any. x + 5y = 6 6x - 15y = 18
*Saturday, September 27, 2014 at 2:22am*

**Accounting 5**

Bethany Link delivers parts for several local auto parts stores. She charges clients $0.75 per mile driven. She has determined that if she drives 2,100 miles in a month, her average operating cost is $0.55 per mile. If Bethany drives 4,200 miles in a month, her average ...
*Friday, September 26, 2014 at 11:11pm*

**chemistry**

An electrical heater delivers 4.070 kJ of energy (as heat) to a system consisting of the gas inside a cylinder having a movable piston. As a result, the piston moves against a constant external pressure such that P ∆V = 2.442 kJ. What is the change in internal energy for...
*Friday, September 26, 2014 at 7:39pm*

**Accounting**

Anheuser-Busch InBev Companies, Inc reported the following operating information for a recent year. In addition assume that Anheuser-Busch InBev sold 200 million barrels of beer during the year. Assume that variable costs were 75% of the cost of goods sold and 40% of selling, ...
*Friday, September 26, 2014 at 5:34pm*

**algebra 2**

solve each system of equation by using a table 1. y=3x-4 y=-2x+11 2. 4x-y=1 5x+2y=24 how do you do these?
*Friday, September 26, 2014 at 3:52pm*

**Pre-Calculus**

Help Please Solve the following system of equations. Round your answers to the nearest tenth. Your answer will be in the form: (M,N). Find M + N, rounded to the nearest tenth. 5x+2y=7 -2x+6y=9
*Friday, September 26, 2014 at 11:46am*

**chemistry**

The heat lost or gained by a system is related to its temperature change by a property called its heat capacity. The molar heat capacity of metals at or above room temperature equals 24.92 J/K.mol. The temperature of a block of lead (MM 207.2) was raised by 13.1 degrees when ...
*Thursday, September 25, 2014 at 7:15pm*

**chemistry**

The specific heat capacity of gold at 25°C is 1.290×10-1 J/g/K. For a 5.25×102 g sample of gold, how much will the temperature increase if 6.908×102 J of energy is put into the system? (Assume that the heat capacity is constant over this temperature range.)
*Thursday, September 25, 2014 at 4:54pm*

**Algebra**

In the metric system there are two official temperature scales: degree Celsius and kelvin. The kelvin temperature scale is obtained by shifting the Celsius scale so of any heat whatsoever. An equation about the relationship between the two scales follows: kelvin~ degree ...
*Thursday, September 25, 2014 at 4:17pm*

**HISTORY 2 **

6. which of the following does NOT describe women's work in early Georgia A. Planting and tending a home garden B. Working at the local hospital C. Making clothes for the family D. Taking care of the children** 7. which of the following groups of new settlers in Georgia ...
*Thursday, September 25, 2014 at 3:48pm*

**Physics**

A hanging block of mass X is pressed with a force F at angle theta to the vertical against a frictionless wall and is connected to another hanging block of mass Y by a pulley system. What is the expression for the acceleration of Y?
*Thursday, September 25, 2014 at 2:36pm*

**physics**

Consider the following specific case of the system described in the example above. Suppose the angle θ is 78.0° and the mass of the ball is 7.00 kg.
*Thursday, September 25, 2014 at 1:59pm*

**Chemistry**

Given: CH4 + 2O2 ~ CO2 + 2H2O C - H = 99 kcal O - O = 119 kcal C = O = 192 kcal O - H = 111 kcal Calculate the change in energy for the CH4 - O2 system.
*Thursday, September 25, 2014 at 12:48pm*

**geometry**

In order to properly design a heating system for a greenhouse, the volume of air in the building needs to be determined. Find the volume of air in the greenhouse below. The length of the building is 40 feet long, the width is 20 feet long, and it is 8 feet from the ground to ...
*Wednesday, September 24, 2014 at 6:17pm*

**algebra 2**

Solve the following systems of equations. If the system cannot be solved ,state that it cannot be solved and explain why. 1.3x+y=7 3x+y=10 2. 5x-2y=-24 -4y=-48-10x
*Wednesday, September 24, 2014 at 4:27pm*

**system of equations**

today, johns mom is 5 times as old as he is. in 7 years she will only be 3 times as old. what is johns age today?
*Wednesday, September 24, 2014 at 3:12am*

**physics**

A spring with a spring constant of 53.0 N/m is attached to different masses, and the system is set in motion. What is its period for a mass of 2.7 kg?
*Tuesday, September 23, 2014 at 10:10pm*

**Calculus**

Scorpion Gulch and Western Railway are preparing to build a new line through Rolling Mountains. They have hired you to do some calculations for tunnels and bridges needed on the line. You set up a Cartesian coordinate system with its origin at the entrance to the tunnel ...
*Tuesday, September 23, 2014 at 6:30pm*

**History**

I'm back. I didn't understand the answer yesterday, and I re-read my book, but I'm still confused. Can you help? 1. Why did the system of feudalism arise during the Middle Ages? A. to develop an economic system B. to determine jobs within a city C. to defend the ...
*Tuesday, September 23, 2014 at 10:57am*

**algebra**

what is the system of equation of: 0.25x+0.15y=2.5 1.25x-1.25y=7.5
*Tuesday, September 23, 2014 at 9:14am*