Thursday
September 18, 2014

Posts by John


Total # Posts: 6,240

Chemistry
Ethanol (C2H5OH) boils at a temperature of 78.3oC. What amount of energy, in joules, is necessary to heat to boiling and then completely vaporize a 28.6 g sample of ethanol initially at a temperature of 10.8oC. The specific heat of ethanol is approximately constant at 2.44 JK-...
October 7, 2011

physics
What is its velocity when it returns to the level from which it started? Answer in units of m/s
October 6, 2011

chemistry
How many moles of oxygen combined with aluminum to form 3.8 moles of AL2O3?
October 6, 2011

college algebra
SKILL MAINTENANCE. Calculate: 2b + 8 – 3b = 10 + 11b – 2 – 12b
October 6, 2011

Statistics, Finance
If the distribution of returns for an asset has a variance of zero, then covariance of returns between that asset and the returns any other asset must equal zero. True or False
October 4, 2011

Chemistry
thanks DrBob222
October 4, 2011

Chemistry
How much 1,2-dibromocyclohexane should be obtained by adding bromine in carbon tetrachloride to 1g of cyclohexene
October 4, 2011

chemistry
How many grams of potassium permangate are needed to decolorized 1g of 2-pentene in basic solution
October 4, 2011

Socials
If I were to write an essay on the economic problems of developing countries, what should I write about? Please help. thanks.
October 4, 2011

college chem
Ethanol (C2H5OH) boils at a temperature of 78.3oC. What amount of energy, in joules, is necessary to heat to boiling and then completely vaporize a 20.0 g sample of ethanol initially at a temperature of 13.6oC. The specific heat of ethanol is approximately constant at 2.44 JK-...
October 4, 2011

physics
John is driving at 25m/s. When he brakes, he accelerates at the rate of -5.0m/s^2. How much time did it take him to stop? How far does it take him to stop?
October 3, 2011

physics
A 747 jetliner lands and begins to slow to a stop as it moves along the runway. The mass is 3.1 105 kg, its speed is 25.5 m/s, and the net braking force is 4.24 105 N.(a) What is its speed 7.45 s later?How far has it traveled in this time?
October 3, 2011

Physics
A plane weighing 220 kN (25 tons) lands on an aircraft carrier. The plane is moving horizontally at 67 m/s (150 mi/h) when its tail hook grabs hold of the arresting cables. The cables bring the plane to a stop in a distance of 84 m. (a) How much work is done on the plane by ...
October 3, 2011

physics
Two gears A and B are in contact. The radius of gear A is twice that of gear B. (a) when A’s angular velocity 6.00 Hz counter clockwise, what is B’s angular velocity? (b) If A’s radius to the tip of the teeth is 10.0 cm what is the linear speed of a point on the...
October 3, 2011

physics
The Earth rotates on its own axis once per day (24.0h). What is the tangential speed of the summit of Mt. Kilimanjaro (elevation 5895 m above sea level), which is located approximately on the equator, due to rotation of the Earth? The equatorial radius of Earth is 6378 km.
October 3, 2011

physics help
in a local diner a customer slides an empty coffee cup down the counter for a refill. the cup slides off the counter and strikes the floor at a distance d from the base of the counter. if the height of the counter is h. a) find an expression for the time t it takes the cup to ...
October 3, 2011

Physics
A motorist traveling at 15 m/s encounters a deer in the road 39 m ahead. If the maximum acceleration the vehicle’s brakes are capable of is −6 m/s2, what is the maximum reaction time of the motorist that will allow her or him to avoid hitting the deer? Answer in ...
October 2, 2011

GPA
Can you give me a GPA chart. Please Thank You !!!
October 1, 2011

Math
Find f(infinity) for the complex function: f(z) = (iz-5)/(8z+3i) Thanks, John
September 30, 2011

Science
Can someone please help Thank you. What are the main goals and strategies of green intelligence?
September 29, 2011

Science
Can someone please help me out with these two questions below thank you. 1. What waste disposal methods are available to humans and how might they be more effective? 2. What initiatives or incentives could governments create to better equip citizens for managing their own ...
September 28, 2011

physics
Steve, you are an idiot. A physics problem and why would you assume he threw up. No answer is easy like that.
September 27, 2011

calculus
what does 4 ( x - 5 ) = 4x - 20 equal if x equals 7
September 27, 2011

Algebra 1
290 miles
September 27, 2011

School in General
I was woundering on how exactly grades were curved normally. When instructors apply curves what is generally done? What happens if there's one person in a course that has a perfect score and the rest have like 80% of the points given out during the course. I was just ...
September 26, 2011

English (MLA format)
Hi, I was wondering what was the most proper way to incorporate a quote from a piece of work that is a quote from another piece of work. If this makes no sense... in my paper I'm quoting a quote from a document that we have discussed in class. Within this document the ...
September 26, 2011

Jiska hw help
How do i change my user's color ?
September 26, 2011

Science
What causes a chemical bond to form between atoms ?
September 26, 2011

Math
1170 students are going on trip. they are flying on 138 seat planes. all students must go and all must be seated. how many planes are needed to transport all of the students ?
September 26, 2011

hmyhss manjeri
he is right it doesn't
September 26, 2011

science
thanks
September 26, 2011

science
what causes a chemical bond to form between atoms ?
September 26, 2011

math
ja but all the passengers must go
September 26, 2011

math
there are 1170 students and all need to go on a trip. they will be flying on 138 seat planes. hm planes are neded to transport all the students.
September 26, 2011

Algebra
find any intercepts then graph the linear equation -x+3y=9
September 25, 2011

social studies
I believe its A but not sure.
September 25, 2011

social studies
The study of sensation and perception is important to a psychologist because perception and sensation are the foundation of: A-neurotransmitters and the brain's function. B-memory and how it is experienced in the world. C-the science of neuropsychology. D-learning, ...
September 25, 2011

social studies
:) thank you! D
September 25, 2011

social studies
Humans rely most heavily on the sense of __________, because evolution designed us to be more active during the daytime than at night. A-taste B-touch C-hearing D-sight
September 25, 2011

psychology
I believe it is neurotransmitters and the brain´s function. I just need a second opinion. Thank you
September 25, 2011

psychology
The study of sensation and perception is important to a psychologist because perception and sensation are the foundation of: neurotransmitters and the brain's function. memory and how it is experienced in the world. the science of neuropsychology. learning, thinking, and ...
September 25, 2011

math
A cubic yard is 3 feet long by 3 feet wide by 3 feet tall. (Part A) How many cubic feet are in 1 cubic yard? (Part B) Landscaping mulch costs &1 per cubic foot. What is the cost for 3 cubic yards of landscaping mulch?
September 25, 2011

Physics
An air track glider, 8.0 cm long, blocks light as it goes through a photocell gate. The glider is released from rest on a frictionless inclined track and the gate is positioned so that the glider has travelled 96 cm when it is in the middle of the gate. The timer gives a ...
September 24, 2011

geometry
ab is parallel to cd are cut by transversal ef find m<5 when m<3=80
September 22, 2011

physics
A person walks 41° north of east for 3.77 km. How far would another person walk due north and due east to arrive at the same location?
September 22, 2011

Science
Please help Thank you. Do you think we should have a special tax or a onetime payment that all people make to help improve air quality? Or should this be something that our government should budget on their own? Please answer in 100 words or more Thank you.
September 22, 2011

physics
An airplane needs at least 145 meters of runway to take off. If the plane starts from rest and accelerates uniformly to a take-off speed of 170 km/hr then what is its acceleration in meters/second? How long does it take for the plane to become airborne?
September 22, 2011

Physics
An air track glider, 8.0 cm long, blocks light as it goes through a photocell gate. The glider is released from rest on a frictionless inclined track and the gate is positioned so that the glider has travelled 96 cm when it is in the middle of the gate. The timer gives a ...
September 22, 2011

Science
Please Help Thank you. If you had to argue the benefits of wind energy, what would they be? and What are the risks? can you please answer these question in 120 words or more Thank you.
September 22, 2011

Physics
A drag racer crosses the finish line of a 400.0-m track with a final speed of 104 m/s. (a) Assuming constant acceleration during the race, find the racer’s time and the minimum co efficient of static friction between the tires and the road. (b) If, because of bad tires or...
September 22, 2011

Physics
An air track glider, 8.0 cm long, blocks light as it goes through a photocell gate. The glider is released from rest on a frictionless inclined track and the gate is positioned so that the glider has traveled 96 cm when it is in the middle of the gate. The timer gives a ...
September 22, 2011

Physics
In a movie, a stuntman places himself on the front of a truck as the truck accelerates. The co efficient of friction between the stuntman and the truck is 0.65. The stuntman is not standing on anything but can “stick” to the front of the truck as long as the truck ...
September 22, 2011

physics
i think its 5 x 4.5 plus the initial 5 m= total displacement
September 22, 2011

math
math problem: a snake is 60 inches long. It grows 3 inches every year. How long will it be y years from now?
September 21, 2011

physics
An airplane of mass 2800 Kg has just lifted off the runway. It is gaining altitude at a constant 2.3 M/s while the horizontal component of its velocity is increasing at a rate of 0.86 M/s2. Assume g= 9.81 M/s2. (a) Find the direction of the force exerted on the airplane by the...
September 21, 2011

Physics
An air track glider, 8.0 cm long, blocks light as it goes through a photocell gate. The glider is released from rest on a frictionless inclined track and the gate is positioned so that the glider has travelled 96 cm when it is in the middle of the gate. The timer gives a ...
September 21, 2011

Science
Can someone please help me please thank you. Climate change is an environmental issue in the news almost daily, and air pollution impacts us on a global level. What are the implications of global warming? Do you think the efforts to improve air quality are worth the economic ...
September 20, 2011

MATH
IN MY KIDS HOMEWORK THE NUMBER 3 IS TO THE LEFT AND IT ASKS TO PLACE COUNTERS IN THE FIVE FRAME TO SHOW THE NUMBER. WHAT IS A COUNTER?
September 19, 2011

Physical Science
Can you please go over my answers to see if Im correct Im having trouble in this class. A car with mass 2000kg is held at a height of 1.8 meters by a hydraulic lift. The surface area of the piston inside the lift is 300cm², and the surface area of the input tube at the ...
September 18, 2011

Physics HELP
A hot air balloon is 2.5m above the ground rising at 2m/s. A camera is thrown from the ground at 13m/s. At what height do the camer and balloon meet. Need to know the correct formulas and how to insert the data. Stuck on this question for homework.
September 18, 2011

physics
a hot air ballon is 2.5m high, moving at 2/ms. when someone throws a camera at 13m/s to the baloon. at which height do they meet?
September 18, 2011

Physics
4.79 m/s/s
September 18, 2011

Chemistry
The following are the optical properties of three materials A,B and C. Property A B C reflectivity 0.85 0.15 0.001 Absorptivity 0.1 0.7 0.1 a) Determine the transmissivity of the materials b) which material heats up fastest when illuminated? c) which one will be the most ...
September 18, 2011

Physics
An airplane of mass 2800 Kg has just lifted off the runway. It is gaining altitude at a constant 2.3 M/s while the horizontal component of its velocity is increasing at a rate of 0.86 M/s2. Assume g= 9.81 M/s2. (a) Find the direction of the force exerted on the airplane by the...
September 17, 2011

Math
A company reaches the break - even point when its total revenue equals its total cost. The company sells their product at $ 25 per unit. If their total cost is $ 3,000 plus a unit cost of $ 12 , does the company break - even when 200 units are sold? (a) Yes (b) No
September 15, 2011

Math
A total of $ 15,500 is to be divided between Deedy and Maria. If Deedy is to receive $ 3,000 more than Maria, how much will Maria receive? (a) $ 9,000 (b) $ 6,250 (c) $ 6,000 (d) $ 5,000 (e) $ 10,500
September 15, 2011

math 3b
In a set of 400 values, the mean is 121 and the standard deviation is 14. Estimate how many values fall in betweeb each interval
September 15, 2011

Animal Physiology-Membrane Potential
For #1, I got E(K+) = 60/+1 * log (5mM/140mM) = -87mV I think this is right but I don't the rest
September 15, 2011

Animal Physiology-Membrane Potential
Intracellular Extracellular Na+ 12 mM 160 mM Cl- 7 mM 110 mM K+ 140 mM 5 mM 1.How do you calculate the equilibrium potential for potassium, K+, under these conditions? 2. Assuming that Na+ is the only ion the plasma membrane of this cell is permeable to, at what voltage will ...
September 15, 2011

Vocabulary/social studies
Whats the latin base in the woed aggrandize?
September 15, 2011

Physics
Im having trouble understanding the concept of pressure. Help please! What is the pressure at the bottom of a tube of mercury that is 0.2 m deep? An elephant with a mass of 1000 kg stands on a circus platform that weighs 50 kg. The area of the bottom of the platform is 1.25 m&...
September 15, 2011

Physics
Im having trouble understanding the concept of pressure. Help please! What is the pressure at the bottom of a tube of mercury that is 0.2 m deep? An elephant with a mass of 1000 kg stands on a circus platform that weighs 50 kg. The area of the bottom of the platform is 1.25 m&...
September 15, 2011

math
A book club offer was mailed to a sample of 400 famles. Of these, 80 families ordered books. Next month, the book club offer will be mailed to 20,000 families. What is the predicted number of orders expected from the mailing next month?
September 14, 2011

math
Ned is one of 6 library volunteers. He is also one of 8 playground volunteers. Each week 1 volunteer from each group is randomly chosen from each group to work. (Park A) What is the probability that Ned will be chosen for both groups in the same week? (Park B) Are these events...
September 14, 2011

math
Phyllis made some sandwiches for a family reunion.She made 12 turkey sandwiches, 10 ham sandwiches, and 8 cheese sandwiches . She wrapped the sandwiches in paper but forgot to label them. (Part A) The first person took 2 candwiches what is the probability that the first ...
September 14, 2011

math
eva has 4 quarters, 5 dimes, and 6 nickels in her pocket. She takes out 2 coins without looking. What is the probability that eva picked a dime followed by a quarter?
September 14, 2011

math
What is 7 16/20 + 6 1/20?
September 14, 2011

Science
Can someone please help me with the question below thank you. What do you think is the most viable way to address after effects of the possible peak?
September 14, 2011

physics
Find the electric flux through each surface. (Use any variable or symbol stated above along with the following as necessary: ε0.)
September 14, 2011

physics....answer this!
An airplane of mass 2800 Kg has just lifted off the runway. It is gaining altitude at a constant 2.3 M/s while the horizontal component of its velocity is increasing at a rate of 0.86 M/s2. Assume g= 9.81 M/s2. (a) Find the direction of the force exerted on the airplane by the...
September 14, 2011

math
In 1968, the estimated population of the world was 3,559,028,982 people. When this number is written in expanded form using exponents, one power of 10 would not be represented. Which power of 10? Why?
September 13, 2011

math
Polynomials: -5a3power (4a4power – 3a + 1)
September 13, 2011

college algebra
The goal of this problem is to solve the equation by completing the square. x^2-9x+14=0
September 13, 2011

Math Algebra 2
m1v1 + m2v2=(m1+m2)v3 find m1 If you could please explain it too or show the steps I would appreciate it.
September 13, 2011

college algebra
Perform the indicated operation(s) and express the result in standard form. Leave answers in terms of square roots (do not use decimals). (-9-sqrt-3)^2
September 13, 2011

college algebra
Find the product and enter the real and imaginary parts below. Note that you do not need to type in the since it is already given to you. Simplify your square roots as much as possible. sqrt-27((sqrt-5)-(sqrt-11))
September 13, 2011

math
Find the product and enter the real and imaginary parts below. Note that you do not need to type in the since it is already given to you. Simplify your square roots as much as possible. sqrt-27((sqrt-5)-(sqrt-11))
September 13, 2011

math
Perform the indicated operation(s) and express the result in standard form. Leave answers in terms of square roots (do not use decimals). (-9-sqrt-3)^2
September 13, 2011

Physics
A rocket is launched from rest. After 8.0 min, it is 160 Km above the Earth’s surface and is moving at a speed of 7.6 Km/s. Assuming the rocket moves up in a straight line, what are its (a) average velocity and (b) average acceleration?
September 13, 2011

Physics
A. A small plane departs from point A heading for an airport at point B 480 km due north. The airspeed of the plane is 200 km/h and there is a steady wind of 50 km/h blowing northwest to southeast. Determine the proper heading for the plane. B. How long will the trip take?
September 12, 2011

physics
An airplane of mass 2800 Kg has just lifted off the runway. It is gaining altitude at a constant 2.3 M/s while the horizontal component of its velocity is increasing at a rate of 0.86 M/s2. Assume g= 9.81 M/s2. (a) Find the direction of the force exerted on the airplane by the...
September 12, 2011

Science
what would tides be like if the moon did not exist? a) There would be no tides without the moon's gravity. b) There would be one high tide and one low tide every 24 hours because of the sun's gravity, with the high tide at noon and the low tide at midnight. c) There ...
September 11, 2011

Science
Why doesn't the space station fall toward the earth, instead of remaining in space? a) It is beyond the earth's gravitational pull. B) The earth's gravity is balanced out by the attraction of the sun and other planets. C) Centrifugal force keeps it up. D) It does ...
September 11, 2011

physics
Bob jumps into a pool, after he stops moving and becomes stationary i the water. What happens to his k energy?
September 11, 2011

Physics
0.3857142857
September 11, 2011

physics
Bob jumps into a pool, after he stops moving and becomes stationary i the water. What happens to his k energy?
September 11, 2011

Physical Science
The diving board is 3m above the floor thats all the information i was given
September 11, 2011

Science
Please help Thank you. 1. What will the impact be like for Humanity’s natural resource base and thus economic security if everyone enjoyed the same lifestyle?
September 11, 2011

Science
Can someone please help me with these questions below thank you. 1. What do you think the impact of the earth's climate will be like if everyone enjoyed the same lifestyle? 2. What will it be like for The health of ecosystems and biodiversity? 3. What will the impact be ...
September 10, 2011

Physics
use the face that the speed of light in a vacuum is about 3.00 x10^8 m/s to determine how many kilometers a pulse from a laser beam travels in exactly eighteen hours
September 8, 2011

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