# Posts by Maria

Total # Posts: 1,981

**Chemistry**

The pH of a 0.002 50 mol/L solution of benzoic acid is 3.65. Calculate the Ka for benzoic acid.

*December 20, 2011*

**PHI 105 critical thinking and problem solving**

explaining the relationship between informative, explanatory and persuasive statements and critical thinking

*December 19, 2011*

**nursing**

The ANA'S ethical theories and principles and how it incorporates in its operations. Provide an example of how it applies these theories and principles

*December 17, 2011*

**Math**

f(x)=3/2x-4022

*December 14, 2011*

**physics**

A penny falls from a bridge. At 3.2 seconds it will have fallen ___

*December 14, 2011*

**physics please helpp**

A 1.67-kg block of aluminum at 21.7°C is to be melted and reshaped. How much heat must flow into the block in order to melt it? use the following values: For copper: c_copper=0.386 kJ/kg.K T_fusion=1359 K L_fusion=205 kg/K

*December 11, 2011*

**physics please helpp**

A copper sheet of thickness 2.09 mm is bonded to a steel sheet of thickness 1.35 mm. The outside surface of the copper sheet is held at a temperature of 100.0°C and the steel sheet at 26.3°C. a) Determine the temperature (in °C) of the copper-steel interface? b) ...

*December 10, 2011*

**physics**

A 1.67-kg block of aluminum at 21.7°C is to be melted and reshaped. How much heat must flow into the block in order to melt it? c_aluminum=0.386 kJ/kg.K T_fusion=1359 K L_fusion=205 kg/K

*December 10, 2011*

**physics**

A copper sheet of thickness 2.09 mm is bonded to a steel sheet of thickness 1.35 mm. The outside surface of the copper sheet is held at a temperature of 100.0°C and the steel sheet at 26.3°C a) Determine the temperature (in °C) of the copper-steel interface b) How ...

*December 9, 2011*

**physics**

Suppose 0.0210 kg of steam (at 100.00°C) is added to 0.210 kg of water (initially at 19.5°C.). The water is inside a copper cup of mass 48.9 g. The cup is inside a perfectly insulated calorimetry container that prevents heat flow with the outside environment. Find the ...

*December 9, 2011*

**physics**

A 1.67-kg block of aluminum at 21.7°C is to be melted and reshaped. How much heat must flow into the block in order to melt it? use the following values: For copper: c_copper=0.386 kJ/kg.K T_fusion=1359 K L_fusion=205 kg/K For aluminum: c_aluminum=0.900 kJ/kg.K T_fusion=...

*December 9, 2011*

**physics**

A 1.41-kg aluminum pot contains 2.25 L of water. Both pot and water are initially at 17.5°C. How much heat must flow into the pot and the water to bring their temperature up to 92.7°C? Assume that the effect of water evaporation during the heating process can be ...

*December 9, 2011*

**physics**

Suppose 0.0210 kg of steam (at 100.00°C) is added to 0.210 kg of water (initially at 19.5°C.). The water is inside a copper cup of mass 48.9 g. The cup is inside a perfectly insulated calorimetry container that prevents heat flow with the outside environment. Find the ...

*December 9, 2011*

**calculus**

Find the constants a & b such that the function f(x)={2 if ≤ -1 {ax+b if -1<x<3 {-2 if x ≥3 is continuous on the entire real line

*December 6, 2011*

**epidemiology**

What are some global health issues related to mexico?

*December 4, 2011*

**physics**

A 40 N force is applied to pull the desk horizontally to the right. What is the magnitude (the net force or the total force) acting on the deak ?

*December 1, 2011*

**physics**

A desk weighing 80 N rests on the floor. The coefficient of friction between the floor and the desk is 0.25. What is the frictional force between yhe desk and the surface of the floor?

*December 1, 2011*

**nursing**

What options for political influence might a person pursue in an effort to change public health policy?

*November 27, 2011*

**chemistry**

what is the osmolarity of 0.35M KBr? how to set it up.

*November 25, 2011*

**Spanish**

i believe is the last one(Escribiste Mucho en la Computadora ayer.Me duelen los dedos.) because after you been writing a lot you hand get tired, the other doesn't make any sense for me, good luck.

*November 25, 2011*

**Probability PLEASE HELP**

Tina randomly selects two distinct numbers from the set {1, 2, 3, 4, 5}, and Sergio randomly selects a number from the set {1, 2, . . . , 10}. The probability that Sergio’s number is larger than the sum of the two numbers chosen by Tina is ?

*November 24, 2011*

**Probability PLEASE HELP**

thank you very much. can u help me for other quistion pleasee

*November 24, 2011*

**Probability PLEASE HELP**

A box contains exactly five chips, three red and two white. Chips are randomly removed one at a time without replacement until all the red chips are drawn or all the white chips are drawn. What is the probability that the last chip drawn is white ?

*November 24, 2011*

**Probability Please helpp**

For each integer n ≥ 4, let an denote the base-n number 0:133n. The product a4a5 : : : a99 can be expressed as m/n! where m and n are positive integers and n is as small as possible. What is the value of m?

*November 24, 2011*

**Probability Pțease helpp**

Select numbers a and b between 0 and 1 independently and at random, and let c be their sum. Let A, B, and C be the results when a, b, and c, respectively, are rounded to the nearest integer. What is the probability that A + B = C?

*November 24, 2011*

**Probability Pțease helpp**

Tina randomly selects two distinct numbers from the set {1, 2, 3, 4, 5}, and Sergio randomly selects a number from the set {1, 2, . . . , 10}. The probability that Sergio’s number is larger than the sum of the two numbers chosen by Tina is ?

*November 24, 2011*

**Probability**

A box contains exactly five chips, three red and two white. Chips are randomly • removed one at a time without replacement until all the red chips are drawn or • all the white chips are drawn. What is the probability that the last chip drawn is white? • (

*November 24, 2011*

**calculus**

what is the derivative of x^2(x^2-4)

*November 22, 2011*

**Optimization--PLEASE HELP!!!**

At t=0, ship A is 12 miles due north of ship B. Ship A travels 12 miles/hour due south, while ship B travels 8 miles/hour due east. a. Write a function for the distance between the two ships. b. At what time are the two ships closest?

*November 21, 2011*

**Calculuss--Optimization**

Thank you so much! I appreciate it!

*November 21, 2011*

**Calculuss--Optimization**

At t=0, ship A is 12 miles due north of ship B. Ship A travels 12 miles/hour due south, while ship B travels 8 miles/hour due east. a. Write a function for the distance between the two ships. b. At what time are the two ships closest?

*November 21, 2011*

**physics please helpp**

The ends of the two rods shown in the figure are separated by 2.97 mm at 24.3 °C. The left-hand rod is brass and 1.21 m long; the right-hand rod is steel and 1.21 m long. Assuming that the outside ends of both rods rest firmly against rigid supports, at what temperature ...

*November 21, 2011*

**chemistry**

20.2 g of potassium phosphate is dissolved into 650 ml of H2O yes i so confuse i need to know what property is if is morality , osmolarity , boiling point or if are another property? thank you.

*November 21, 2011*

**chemistry**

20.2 g of potassium phosphate is dissolved into 650 ml of H2O

*November 21, 2011*

**chemistry**

25 G OF CALCIUM CHLORIDE IS DISSOLVED INTO 1500mml OF H2O. how can i set it up.

*November 21, 2011*

**physics**

The ends of the two rods shown in the figure are separated by 2.97 mm at 24.3 °C. The left-hand rod is brass and 1.21 m long; the right-hand rod is steel and 1.21 m long. Assuming that the outside ends of both rods rest firmly against rigid supports, at what temperature ...

*November 21, 2011*

**physics**

The ends of the two rods shown in the figure are separated by 2.97 mm at 24.3 °C. The left-hand rod is brass and 1.21 m long; the right-hand rod is steel and 1.21 m long. Assuming that the outside ends of both rods rest firmly against rigid supports, at what temperature ...

*November 21, 2011*

**physics**

The ends of the two rods shown in the figure are separated by 2.97 mm at 24.3 °C. The left-hand rod is brass and 1.21 m long; the right-hand rod is steel and 1.21 m long. Assuming that the outside ends of both rods rest firmly against rigid supports, at what temperature ...

*November 21, 2011*

**physics**

3.9 cm it's not true :(

*November 21, 2011*

**physics**

Your physics teacher assigned a thermometer-building project. He gave you a glass tube with an inside diameter of 1.15 mm and a receptacle at one end. He also gave you 8.97 cm^3 of mercury to pour into the tube, which filled the receptacle and some of the tube. You are to add ...

*November 21, 2011*

**science**

The heaviest invertebrate is the giant squid which can have a weight of 1.6 tons spread out over its lenght of 60 feet. What is its weight in newtons?

*November 20, 2011*

**physics**

A college student is at a concert and really wants to hear the music, so she sits between two in-phase loudspeakers, which point toward each other and are 60.8 m apart. The speakers emit sound at a frequency of 428.75 Hz. At the midpoint between the speakers, there will be ...

*November 17, 2011*

**physics**

The sound level in decibels is typically expressed as β = 10 log (I/I0), but since sound is a pressure wave, the sound level can be expressed in terms of a pressure difference. Intensity depends on the amplitude squared, so the expression is β = 20 log (P/P0), where ...

*November 17, 2011*

**Math**

subtract 15 from 17. it cancels o the left side. You're left with y/3.5=2 Now make it like a fraction y/3.5=2/1 Do the butterfly 3.5*2=7 7/1=7 7 is your answer i think.

*November 16, 2011*

**physics**

Using Newton's Law of Universal Gravitation, compare the weight of a 68.1 kg astronaut on the surface of the earth to the gravitational pull of the Earth on the same astronaut when she is on the International Space Station. Constants: Average altitude of the ISS above the ...

*November 16, 2011*

**physics**

Using Newton's Law of Universal Gravitation, compare the weight of a 68.1 kg astronaut on the surface of the earth to the gravitational pull of the Earth on the same astronaut when she is on the International Space Station. Constants: Average altitude of the ISS above the ...

*November 16, 2011*

**physics**

Using the weight equation, weight = (mass)(strength of gravity field) or Fg = mg, calculate your mass in kilograms. Constants: Strength of the gravity field near the surface of the earth, g = 9.8 m/s2. 4.448 Newtons equals one pound of force. You can find the other constants ...

*November 16, 2011*

**physics**

Using Newton's Law of Universal Gravitation, compare the effect of the Sun and the Moon on the tides. Constants: Mass of the Moon, M☽= 7.348E22 kg. Moon's semi-major axis, a☽= 3.844E8 m. You can find the other constants you will need on the Astronomy ...

*November 16, 2011*

**physics**

A college student is at a concert and really wants to hear the music, so she sits between two in-phase loudspeakers, which point toward each other and are 60.8 m apart. The speakers emit sound at a frequency of 428.75 Hz. At the midpoint between the speakers, there will be ...

*November 16, 2011*

**physics**

Using Newton's Law of Universal Gravitation, compare the gravitational pull of the Sun on the Earth to the gravitational pull of the Moon on the Earth. Constants: Mass of the Moon, M☽= 7.348E22 kg. Moon's semi-major axis, a☽= 3.844E8 m. You can find the ...

*November 16, 2011*

**physics**

A college student is at a concert and really wants to hear the music, so she sits between two in-phase loudspeakers, which point toward each other and are 60.8 m apart. The speakers emit sound at a frequency of 428.75 Hz. At the midpoint between the speakers, there will be ...

*November 16, 2011*

**physics**

The sound level in decibels is typically expressed as β = 10 log (I/I0), but since sound is a pressure wave, the sound level can be expressed in terms of a pressure difference. Intensity depends on the amplitude squared, so the expression is β = 20 log (P/P0), where ...

*November 16, 2011*

**physics**

You drop a stone down a well that is 12.37 m deep. How long is it before you hear the splash? The speed of sound in air is 343 m/s.

*November 15, 2011*

**physics**

A policeman with a very good ear and a good understanding of the Doppler effect stands on the shoulder of a freeway assisting a crew in a 40-mph work zone. He notices a car approaching that is honking its horn. As the car gets closer, the policeman hears the sound of the horn ...

*November 15, 2011*

**ASAP ENGLISH PAPER**

i am writing a paper for English the question is what ethical problems may rise in research on humans?List and describe the three principles researchers are supposed to be guided by in resolving dilemmas. I AM STUCK PLEASE HELP ME!!!!!!

*November 14, 2011*

**Calculus--Please Help!**

A 13-foot ladder is leaning against a vertical wall. If the bottom of the ladder is being pulled away at a rate of 2 feet per second, how fast is the area of the triangle formed by the wall, the ground, and the ladder changing when the bottom is 12 feet away from the wall?

*November 13, 2011*

**Question (answer quick)**

No problem =)

*November 13, 2011*

**Question (answer quick)**

I would most likely go with A.

*November 13, 2011*

**english**

The sentence "The exhibits show all different varieties of cheeses and breads..." I believe contains an error. In that sentence, since you have made the word "variety" plural, you should not have s's after cheese and and bread. In other words, it should...

*November 13, 2011*

**College Calculus**

A 13-foot ladder is leaning against a vertical wall. If the bottom of the ladder is being pulled away at a rate of 2 feet per second, how fast is the area of the triangle formed by the wall, the ground, and the ladder changing when the bottom is 12 feet away from the wall?

*November 13, 2011*

**Calculus**

find the derivative of: (x^2+y^2)^2=x^2-y^2

*November 13, 2011*

**Calculus**

find the derivative of: (x^2+y^2)^2=x^2-y^2

*November 13, 2011*

**English**

Oxymoron because it contains two contradictory words. a crime cannot be holy

*November 13, 2011*

**math2**

Dan had to complete the remaining 1/3 of his science project this week. On Monday, he completed 4/5 of the work he had left to do. What part of the entire project did Dan complete on Monday? Can you guide me on how to figure it out?

*November 10, 2011*

**math**

Dan had to complete the remaining 1/3 of his science project this week. On Monday, he completed 4/5 of the work he had left to do. What part of the entire project did Dan complete on Monday?

*November 10, 2011*

**Math**

Thank you Steve

*November 8, 2011*

**Math**

one angle of a triangle is 90 degrees. If the ratio of the legs i 1:1, what are the mesuares( in degrees) of the 2 remaining angles?

*November 8, 2011*

**chemistry**

consider C3H8+O2=CO2+H20 how much oxygen would be needed to completely burn 250g of propane

*November 6, 2011*

**Chemistry -buffers.**

**1 mole of CO2 at stp is 22.26L Pka=6.1 at 37C Solubility coefecient =0.031 mmol/LmmHg at 37 C

*November 6, 2011*

**Chemistry -buffers.**

The pH of an arterial blood sample is 7.15. upon acidification of 10 ml of the plasma 5.91ml of CO2 is produced at standard temperature and presure. Calculate-a) total CO2 in the specimen b)the individual concentration of disolved CO2(H2CO3) and HCO3- c)The partial pressure of...

*November 6, 2011*

**Chemistry**

If in an experimental reaction 32.5 mL were collected of hydrogen gas at 23.5 degrees celsius and 745.2 Torr what would be the volume corrected to STP conditions?

*November 3, 2011*

**global healh and nursing**

how and why do nurses use the epidemiology methods and data?

*November 2, 2011*

**calculus**

A rectangular beam is cut from a cylindrical log of radius 25 cm. The strength of a beam of width w and height h is proportional to wh2. (See Figure 4.70.) Find the width and height of the beam of maximum strength.

*November 1, 2011*

**nursing**

Why is epidemiology important in the study of health and disease in communities

*November 1, 2011*

**Math**

google "rule of 72"

*October 31, 2011*

**geometry**

Looking at formulas, which 2 shapes describe this relationship: the area of the 2 dimensional shape is one-fourth the surface area of the 3-demensional figure? Looking at formulas, which two figures describes this relationship: the volume of the first 3-dimensional figure is ...

*October 30, 2011*

**physics**

Find the minimum diameter of a 51.5-m-long nylon string that will stretch no more than 1.01 cm when a load of 68.9 kg is suspended from its lower end. Assume that Ynylon = 3.51·10^8 N/m2 physics - bobpursley, Saturday, October 29, 2011 at 10:32am Hookes Law: elongation...

*October 30, 2011*

**physics**

yes I know. I solved with the value of elongation 0.0101 m. and I've found diameter 0.11 ! But it's wrong :( I tried many times and i always found 0.11 diameter.. I don't know where is the problem..

*October 30, 2011*

**physics**

Find the minimum diameter of a 51.5-m-long nylon string that will stretch no more than 1.01 cm when a load of 68.9 kg is suspended from its lower end. Assume that Ynylon = 3.51·10^8 N/m2 physics - bobpursley, Saturday, October 29, 2011 at 10:32am Hookes Law: elongation...

*October 30, 2011*

**physics**

Find the minimum diameter of a 51.5-m-long nylon string that will stretch no more than 1.01 cm when a load of 68.9 kg is suspended from its lower end. Assume that Ynylon = 3.51·108 N/m2

*October 29, 2011*

**PSY Quiz**

Question 3 of 10 0.0/ 2.0 Points Which of the following is an effective approach for estimating heritability of a trait or behavior? D. Comparing twins to determine whether identical twins are more alike than are fraternal twins Question 9 of 10 0.0/ 2.0 Points A culture in ...

*October 27, 2011*

**7th grade Algebra**

4w-9(6-5w)=44;w=3 decide whether the given value is a solution of the equation if not find the solution

*October 26, 2011*

**nursing**

bioterrorism and how might you prepare for its effects?

*October 26, 2011*

**physics**

An open-topped tank completely filled with water has a release valve near its bottom. The valve is 1.63 m below the water surface. Water is released from the valve to power a turbine, which generates electricity. The area of the top of the tank, AT, is a = 12.3 times the cross...

*October 26, 2011*

**physics**

Donald Duck and his nephews manage to sink Uncle Scrooge's yacht (m = 4843 kg), which is made of steel (ρ = 7850 kg/m3). In typical comic-book fashion, they decide to raise the yacht (which is now on the bottom of a lake) by filling it with ping-pong balls. A ping-...

*October 26, 2011*

**physics**

thank you drwls !

*October 26, 2011*

**physics**

A hollow rubber ball with a diameter of 5.57 cm and a mass of 38.9 g is cut in half to make a boat (in a bathtub) for American pennies made after 1982. The mass and volume of an American penny made after 1982 are 2.5 g and 0.36 cm3. How many pennies can be placed in the boat ...

*October 26, 2011*

**nursing**

Because water is an essential requirement for sustaining life, why is local or international water assessment necessary to prevent disease?

*October 25, 2011*

**physics**

Find the minimum diameter of a 51.5-m-long nylon string that will stretch no more than 1.01 cm when a load of 68.9 kg is suspended from its lower end. Assume that Ynylon = 3.51·108 N/m2.

*October 25, 2011*

**physics**

A hollow rubber ball with a diameter of 5.57 cm and a mass of 38.9 g is cut in half to make a boat (in a bathtub) for American pennies made after 1982. The mass and volume of an American penny made after 1982 are 2.5 g and 0.36 cm3. How many pennies can be placed in the boat ...

*October 25, 2011*

**physics**

A sinusoidal wave on a string is described by the equation y = (0.169 m) sin (0.713 x - 41.9 t), where x and y are in meters and t is in seconds. If the linear mass density of the string is 10.1 g/m .. if needs values of these ( the speed of the wave is 58.77 m/s) (the ...

*October 25, 2011*

**Geometry**

The distance between two docks on opposite sides of a river is 90 meters. The angle formed by the river bank and the line between the docks is 53°. What is the width of the river? Round your answer to the nearest meter and show your work.

*October 25, 2011*

**Geometry**

The distance across a lake is 34 meters. What is the distance, h, between the boat ramp and the dock? Round your answer to the nearest meter and show your work.

*October 25, 2011*

**physics**

(d) Wave pwer is proportional to frequency and Amplitude^2. f=6.669 Hz u=10.1 g/m A=0.169 m W=41.9 I tried with the power transmitted formula power=0.5*u*W^2*A^2*v But my solution is wrong :( I can not find a) and d) :(

*October 25, 2011*

**physics**

a) ... the phase of the wave at x = 2.27 cm and t = 0.175 s. ? yes x is 2.27 cm. in meter is 0.0227m !

*October 25, 2011*

**physics**

A sinusoidal wave on a string is described by the equation y = (0.169 m) sin (0.713 x - 41.9 t), where x and y are in meters and t is in seconds. If the linear mass density of the string is 10.1 g/m ... a) ... the phase of the wave at x = 2.27 cm and t = 0.175 s. ? b)... the ...

*October 25, 2011*

**math**

if you start from the bottom, you get 16, then 27 then 38 27 is greater than 25 and less than 35

*October 24, 2011*

**algebra**

does 6^2 + 20^2 = 21^2 ?

*October 24, 2011*

**Alegra Beginning**

ok, (2 x Tom) + Tom = 48,000 + 6,000 3 Tom = 54,000 Tom = 54,000 / 3 Can you figure out the rest?

*October 24, 2011*

**Alegra Beginning**

Rachel = (2 x Tom) - 6,000 Rachel + Tom = 48,000 so, (2 x Tom) - 6,000 + Tom = 48,000 can you solve it from here?

*October 24, 2011*