Wednesday

April 23, 2014

April 23, 2014

Total # Posts: 3,112

**Physics**

An engineer claims to have measured the characteristics of a heat engine that takes in 130J of thermal energy and produces 40J of useful work. What is the smallest possible ratio of the temperatures (in kelvin) of the hot and cold reservoirs?

**Physics**

The oven draws 1100W of power, and you have determined that it heats with an efficiency of 51%. Using this information, determine the time t it would take to bring 240mL of water from 25C to 100C . Note that 4.2 J of energy is required to raise the temperature of 1.0mL of wate...

**history**

how did former president nixon pardon impact the united states?

**ALgebra word problem**

sorry. i dont really know

**ALgebra word problem**

one number is 6 more than another. their product is 91. what is the number?

**Find the maximum value of this function**

f(x) = 9 sqrt(x)e*(-x)

**algebra**

the length of a pool is 30 meters greater than the width. if the area is 1000 square meters, find the dimensions of the pool.

**Spanish**

14. c 15. i think its a

**algebra**

1. 100x^2-9 2. 8x^2+14x+6

**math**

Consumers pay for electricity by the kilowatt-hour (the amount of electricity used by a 1,000-watt appliance in one hour). If electricity costs 10cents per kilowatt-hour, what is the cost of running a 100-watt lamp for 1. 1 hour? 2. 24 hours? 3. 1 year?

**Math**

Consider the equation below. (Round the answers to three decimal places. If you need to use -infinity or infinity, enter -INFINITY or INFINITY.) f(x) = 9 sqrt(xe*^(-x) (a) Find the interval on which f is increasing. ( , ) Find the interval on which f is decreasing. ( , ) (b) F...

**math**

A ball is dropped from a height of 5 ft. Assuming that on each bounce the ball rebounds to one-third of its previous height, find the total distance travelled by the ball.

**Evaluating limits**

Evaluate the limit. (If you need to use - or , enter -INFINITY or INFINITY.) lim x +sin(x)/(2x+cos(x)) as x goes to 0.

**L'hospital rule**

Evaluate the limit. lim (cos(x))^(7/x^2) as x goes x-->0^+

**Chemistry!**

PV=nRT should be used

**math**

If a normal studentblinks 25 times per minute how old yould you be your next birthday?

**math**

the remainder is 3 and the answer is 44

**algebra**

1) 27x^3+8 2) 3x^2-x-4

**algebra**

Add. 5x^2-8x^3+3x-2 and 4x^3+5x^2+9-x

**Math**

12y^2+16-13 I cant seem to get the right answer please help

**algebra**

LOG5(X+7)=LOG3(X-4)+LOG3(X_2-LOG3 X=

**algebra**

(a-b)(a^2+ab+b^2)

**math**

thank you guys :) a lot

**math**

the circumference of a wheel is one yard. If the wheel is pushed half a mile, how many times will the wheel go around (1 mi = 5280 ft)

**Social Studies**

What were one cause and one effect of the American Revolution?

**Physics**

A spring is hung from the ceiling. When a coffee mug is attached to its end, it stretches 3.0 cm before reaching its new equilibrium length. The block is then pulled down slightly and released. What is the frequency of oscillation?

**Organic Chem I Lab**

DrBob222 how about some help here?

**art**

I have an image by Takashi Murakami.that I need a professional opinion for complete a detailed analysis of the image using all the visual elements and principles of design. The image is Tan Tan Bo Puking—a.k.a. Gero Tan (2002).

**Physics**

The speed limit on a particular freeway is 28.0 m/s (about 101 km/hour). A car that is merging onto the freeway is capable of accelerating at 6.50 m/s2. If the car is currently traveling forward at 13.0 m/s, what is the shortest amount of time it could take the vehicle to reac...

**chemistry**

it only tells me that and that gypsum contains 2 moles of water for each 1 mole of calcium sulfate from CaSO4*2H20

**chemistry**

what is the percent composition by mass of water in a compound with a gram formula mass of 4905 g/mol

**physics help please**

a horizontal force of 8.0 newtons is used to pull a 20.-newton wooden box moving toward the right along a horizantal, wood surface, as shown. A. Determine the mass of the box. B. calculate the magnitude of the acceleration of the box.[Show all work, including the equation and ...

**need physics help**

d=2.1 a=? vi=0 and t=.60 and i have to use the formula d=vit+1/2at^2, how do i do this? can you please show work so i can understand.

**Microeconomincs**

Find an article that deals with business impact on the environment. and i want to know what does business impact on the environment mean?

**Math**

I need Help in the study unit for pennfoster on The Accounting Equation please!!!!!!!!!!! THANK YOU

**Physics**

A carbon dioxide laser is an infrared laser. A CO2 laser with a cavity length of 48.4 cm oscillates in the m=100,000.0 mode. 1. What is the wavelength of the laser beam? 2. What is the frequency of the laser beam?

**Physics**

What is the longest wavelength for standing sound waves in a 108.0 cm long tube that is open at both ends? What is the second longest wavelength? What is the third longest wavelength?

**Physics**

since when did physics problems have to make sense

**Physics**

During the Olympic ice competition, Boris (m = 75 kg) glides at 1.8 m/s to a stationary Juliette (52 kg) and hangs on. How far will the pair slide after the “collision” if the coefficient of kinetic friction between the ice and their skates is .042? My answer: Conser...

**Economics**

# How can American consumers influence decision makers on fiscal policies? # Explain and discuss if and how this has changed over the past 5 years.

**algebra**

factor. 3x+x^2-10

**CHEM 136**

hey did you figure this out....if so what answers did you get

**Physics**

Earthquakes are essentially sound waves travelling through the earth. They are called seismic waves. Because the earth is solid, it can support both longitudinal and transverse sismic waves, which travel at different speeds. The speed of longitudinal waves, called P waves, is ...

**Algebra: Simple Interest**

a loan of 25,000 its due in 9 months with an annual interest rate of 10%. Find the total amount that will be due.

**physics**

In a device known as an Atwood machine, two masses m1=10kg and m2=20kg are connected by rope over a frictionless pulley. What is the acceleration of each mass if the rope is massless?

**Physics**

Suppose with 200 N of force applied horizontally to your 1500 N refrigerator that is slides across your kitchen floor at a constant velocity. What are thre friction forces on the refrigerator?

**Physics**

As the initially empty urinary bladder fills with urine and expands, its internal pressure increases by 3600 Pa, which triggers the micturition reflex (the feeling of the need to urinate). The horizontal square section of the bladder wall with an edge length of 0.012 m. Becaus...

**Physics**

A gold prospector finds a solid rock that is composed solely of quartz and gold. The mass and volume of the rock are, respectively, 14.8 kg and 1.89 × 10-3 m3. The density of gold is 19 300 kg/m3, and the density of quartz is 2660 kg/m3. Find the mass of the gold in the ...

**Physics**

A die is designed to punch holes of radii 2.17 x 10-2 m in a metal sheet that is 5.53 x 10-3 m thick. To punch through the sheet, the die must exert a shearing stress of 3.5 x 108 Pa. What force must be applied to the die? (Hint: Consider carefully which area is used in your c...

**Physics**

Between each pair of vertebrae in the spinal column is a cylindrical disc of cartilage. Typically, this disc has a radius of about 2.6 x 10-2 m and a thickness of about 1.4 x 10-3 m. The shear modulus of cartilage is 1.2 x 107 N/m2. Suppose a shearing force of magnitude 18 N i...

**physics**

what is the variation of pressure in the sound wave if the sound intensity is 3.85x10^-8 W/m^2, the speed of sound is 343 m/s and the density of air is 1.2 kg/m3?

**Physics**

what is the variation of pressure in the sound wave if the sound intensity is 3.85x10^-8 W/m^2, the speed of sound is 343 m/s and the density of air is 1.2 kg/m3?

**Physics**

How would I do that?

**Physics**

A microphone has an area of 3.8 cm2. It receives during a 2.87 s time period a sound energy of 4.2x10-11 J. What is the intensity of the sound?

**Physics**

A microphone has an area of 3.8 cm2. It receives during a 2.87 s time period a sound energy of 4.2x10-11 J. What is the intensity of the sound?

**Physics**

The answer seems to be wrong when I submit.

**algebra word problems**

1) tina has 48 mL of a solution that is 25% acid. how much water should she add to obtain a solution that is 15% acid? 2) how many grams of sugar must be added to 60 grams of a 32% solution to obtain a 50% solution?

**algebra word problems**

you have 95 coins that total $10.75. the coins consist of only quarters and nickels. how many of each coin do you have?

**ALgebra word problem**

a coffee shop sells a cup of espresso for $2.00 and a cup of cappuccino for 2.50. on friday, rachel sold 30 more cups of cappuccino than espresso, and she sold $178.50 worth of espresso and cappuccino together. how many cups of each were sold?

**Economics**

You want to start a company, and are trying to decide between two different industries. You are doing your final research before you write your business plan. Industry A has 20 firms and a Concentration Ratio (CR) of 20% * What is the name for this type of industry? * Describe...

**grade 12 data management**

Q- 2 cards are drawn without replacement from a deck of 52 cards. What is the probability that the both card are aces given that they are the same color? I am having a hard time with this question. If anyone knows this I would appreciate it very much thanks.

**geometry**

A rectangular rug covers the floor in a living room. One of the walls in the same living room is pained blue. Are the rug and the blue wall parallel?

**ALgebra**

multiply 1) (x-3)^3. 2) (2x+y)^3. 3) (3a-2)^3

**history**

Why would some people find it wrong to have a woman president for to represent their country?

**ALgebra**

multiply. (x+2)(x-2)(x^2+4)

**Physics**

A block attached to a spring with unknown spring constant oscillates with a period of 6.0 s. What is the period if the mass is doubled?

**Math**

THe total ticket sales for the basketball game were $1,625.00. Adult tickets were $7.00, and student tickets were $3.00. Twice as many students bought tickets as adults. How many student and adult tickets were sold?

**biopsychology**

Explain to little brother or sister how neours and synapses work

**11th grade**

What measures does henry say the colonists have already tried in the dealings with england?

**math**

Evaluate (3 + 4) + 1 in the mod 5 system

**Physics**

One gram of water changes from liquid to solid at a constant pressure of 1.00 atm and a constant temperature of 0°C. In the process, the volume changes from 1.00 cm3 to 1.14 cm3

**Physics**

A man of mass 65.2 kg stands on a scaffold supported by a vertical rope at each end. The scaffold has a mass of 22.7 kg and is 2.4 m long. Suppose the man stands to the right from the middle of the scaffold that is a distance one sixth of the length of the scaffold. what is th...

**Physics**

So i multiply 0.69 by ?? 0.345?

**Physics**

A square, 0.69 m on a side, is mounted so that it can rotate about an axis that passes through the center of the square. This axis is perpendicular to the plane of the square. A force of 17.1 N lies in this plane and is applied to the square. What is the magnitude of the maxim...

**Physics**

How about for the left rope? Would it be the same thing? or negative instead?

**Physics**

A man of mass 65.2 kg stands on a scaffold supported by a vertical rope at each end. The scaffold has a mass of 22.7 kg and is 2.4 m long. Suppose the man stands to the right from the middle of the scaffold that is a distance one sixth of the length of the scaffold. What is th...

**Chemistry**

Calculate Delta G for the spontaneous cell produced from the following: Al^3+ + 3e^- -> Al (s) Mg^2+ + 2e^- -> Mg (s) In order to solve this, you need to determine the half reactions..ie which is reduced and which is oxidized. How do I know which one is being reduced and...

**ALgebra**

simplify (-2x^-4) (8x^-3)

**ALgebra**

simplify (-2x^3)^2 (3x^-2)

**ALgebra**

simplify 4z-[23-5(3z-2)]

**English quick ?**

yes i believe there is

**Trig**

tan^2t/sect=sect-cost cott^2/csct=csct-sint

**Physics**

A space vehicle is traveling at 5260 km/h relative to Earth when the exhausted rocket motor is disengaged and sent backward with a speed of 89 km/h relative to the command module. The mass of the motor is four times the mass of the module. What is the speed (in km/h) of the co...

**history**

what are some of the ways in which modern culture is "fatalistic" (in the ancient Greek sense of the word?

**ALgebra**

f=m(m/g^2) solve for m

**ALgebra**

solve 3x-8>2x-1

**Physics**

A 25 kg child bounces on a pogo stick. The pogo stick has a spring with spring constant 2.0*10^4 N/m. When the child makes a nice big bounce, he finds that at the bottom of the bounce he is accelerating upwards at 9.8 m/s^2. How much is the spring compressed?

**ALgebra word problem**

monthly credit card interest is charged at a rate of 1.5%. after one month, total purchases plus interest equal $46.69. how much were the purchases?

**ALgebra**

yes they were two different problems and yes i know they're stupid questions in my math book.

**ALgebra**

simplify: (2x^2y)(-5x^-5y^6) (5y)^3

**college**

convert 2(NH4)3PO4+3HgSO4=3(NH4)2SO4+Hg3(PO4)2 into complete ionic equation,then net ionic equation

**algebra**

can you tell me the process of how to simply problems like this so i dont have to keep asking? simplify: (2x^2y)(-5x^-5y^6) (5y)^3

**ALgebra**

a swim club requires a $120 membership, plus $4 each swim. How much would a person pay to swim 35 times?

**math**

whats square root of 16

**Physics**

i tried both ways and both are wrong :s

**Physics**

So tan theta = 20.8/3.7?

**Physics**

What do you mean by convert it to your system?

**Physics**

Forces of 10.6 N north, 20.8 N east, and 14.3 N south are simultaneously applied to a 3.76 kg mass as it rests on an air table. What is the magnitude of its acceleration? What is the direction of the acceleration in degrees? (Take east to be 0 degrees and counterclockwise to b...

**Physics**

A 2.03 kg mass is observed to accelerate at 8.82 m/s2 in a direction 28.8° north of east. There is a force directed north acting on the object and a force directed east acting on the object. What is the magnitude of the force acting east on the object?

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